By Tina Perinotto

13 February 2012 –UPDATED 14 February 2012 –  A wide ranging survey and technical review of the NABERS sustainability rating scheme was delivered by the Australian Institute of Refrigeration, Air Conditioning and Heating, late last week.

A key message was strong support for the system but with plenty of suggestions for a more streamlined, robust  system.

The survey, organised  by AIRAH on behalf of the NABERS stakeholder advisory committee, nominated priority issues such as whether the tools should be emissions or efficiency based; stretch targets and incremental ratings for the star rating system; transparency in the development of benchmarks and normalisation factors and reducing complexity.

Priority technical issues included methods to determine hours of occupancy, building, space and activity classification, the use and calibration of meters and sub meters, the treatment of data rooms in the tools and the methods specified for microbiological sampling and testing of the indoor air.

Chief executive officer of AIRAH Phil Wilkinson said: “The survey has really highlighted how well accepted the NABERS rating tools are and that industry really wants to be actively engaged in improving the suite of tools.

“A lot of technical issues have been raised and I think we as industry need to be realistic about how quickly the items can be dealt with,” he said.

There needed to be awareness that there was an element of “work in progress” with the rating tool and that it was important to co-operate to get it right, Mr Wilkinson said.

“We are very encouraged by the formation of the NABERS stakeholder advisory committee and the willingness of stakeholders and government to work together to improve this importunate set of tools.”

The NSW Office of Environment and Heritage, which manages NABERS, said it was pleased with the feedback.

Matthew Clark, director water and energy programs, Office of Environment and Heritage said: “We look forward to studying the findings in detail and working through the issues raised to ensure that NABERS remains a robust and reliable system, continued to be held in high regard by industry.”

Director of WT Sustainability Steve Hennessey said some useful comments came from the survey.

“I thought it was good, no surprises, and some useful things that came out of it. They had interesting range of responses: how positive people are about NABERS.

“Almost all the comments were collaborative and constructive But as with any system there are things that can be improved.”

Following are the key findings from the survey

All in all a very useful rating tool; NABERS provides a credible result that is clear and comparable.  A few minor changes (only) would help improve energy efficiencies within buildings.
Excellent tools.  Once project managers and designers understand that the ‘she’ll be right’ attitude and fobbing off of design elements to contractors will not deliver high performance buildings, the building industry will improve substantially.  The failure in ‘attention to detail’ is often the source of cost and time over-runs.
I think it is a useful tool to use and certainly in my experience have not had any issues with its use.  I have predominately been using the NABERS Office tools and found them very easy and simple to use.
NABERS is a program that is very applicable in terms of energy efficiency assessment and much more work can be done to improve the program to meet energy efficiency targets as well as greenhouse gas emission reduction.  There are a few similar programs on the market and I wish the agency would consult with other program designers.
As a regular Assessor and also Supervisor and Trainer, I’m a strong supporter of NABERS and believe its uptake even before Commercial Building Disclosure shows its increasing acceptance.  Having said that it is important the Rules keep up with the times, so reviews like this definitely have value, particularly for more strategic issues rather than small technical ones.
NABERS?  I love it!
Well established tools with good market acceptance.  Needs to continue to refine/define it to remove ambiguity and inconsistencies.
Excellent system. Very glad to have it. Need to focus on keeping it streamlined. It is meant to be fast and effective, over time more and more clauses being added. Will need someone to take stock periodically with intention to streamline.
The introduction of mandatory disclosure is resulting in a large increase in ratings.  The strategic review needs to look closely at the extent that the rating process can be streamlined whilst maintaining its credibility.
Love it, really, really important, but needs some care, industry is willing.
NABERS is otherwise an excellent system which has achieved great results.  There are loopholes that are being exploited by unscrupulous designers and needs to be plugged.
Overall I believe NABERS to be a useful rating tool with a high-level of rigour applied in its methodology.
NABERS is a very important part of the shift in thinking about resource efficiency and GHG emission reduction.  It may never be perfect, but no benchmarking system ever will be.
Logically development/enhancement of the tool has been focused on NABERS Energy for offices due to the link to mandatory disclosure legislation, but adequate support should be given to the other tools (i.e. retail) so these don’t lag behind.
I think there are a lot of issues with the NABERS program especially considering that some parts of it have become legislation.
NABERS should be used in all building classifications
Good concept, just need wider / more people using it

Specific technical issues

The specific technical issues highlighted in the survey are listed under the following headings:

  • NABERSAll/Multiple tools–Comments and issues relating to NABERS generally
  • NABERS Energy – Further categorised into; benchmarking, general application, building/space types, occupancy and activities, systems, anddata rooms.
  • NABERSEnergy – Commitment agreements
  • NABERS Retail
  • NABERS Hotels
  • NABERS Water
  • NABERS Indoor Environment (IE)
  • NABERS Waste
  • NABERS Data Centres – Tool in development

NABERS- All/Multiple tools

The following issues were identified for all or multiple NABERS tools.

Application to all buildings/small assets

Issue raisedIt is simply not easy to rate every building the same way the structure allows.  We have issues almost with every building, particularly smaller suburban or regional locations.
Suggested fixIdeally a more flexible approach which can be easily grappled by one size not fitting all.
CommentExtreme annoyance and frustration with current situation.
CommentReduced ratings or inability to get ratings.
CommentGreat idea, but the mandate is a problem for smaller assets in the regions. Little is clearly understood and where a building does not fit the ‘box’ you have a lot of problems, little ability to maintain any degree of flexibility, little control and a great load of frustration. Great concept, but in practice not great for smaller assets. Large assets it works well.

Reverse calculators

Issue raisedNo reverse calculators readily available for all tools.
Suggested fixMake reverse calculators available for all tools.
CommentSome already provided but need to be requested

Rating expiry dates

Issue raisedAll NABERS Rating Tools – For about 18 months now a rating has a specific expiry date (previously this was a month). When a renewal rating is completed the new expiry date is then set to the date that the rating was validated. Mandatory Disclosure legislation has meant that property owners have to be careful to not allow a rating to expire. In effect this means that the re-rating is completed prior to the expiry of the current one, meaning that the expiry dates creep backwards over time.
Suggested fixA re-rating submitted within +/- 4 weeks of an existing rating should have the rating date set to the anniversary of the existing rating date, not the date that the rating is validated.
CommentCurrent arrangements mean that in effect a rating does not stay valid for twelve months.

Stretch targets

Issue raisedNABERS energy and water – Should go to 7 stars.

7 stars being carbon or water neutral from onsite sources.

Suggested fixIf you make NABERS go to 7 stars and this is carbon or water neutral from onsite sources then you have set the end game.  You can have companies that target the highest star, just for the sake of it, but this will stop that unrealistic aim as they will know that the 7 star is extremely difficult.  Make it a 7 star rating system.
CommentIndustry is not aware where the next star will go; will it be a half of 6 stars?  What stretch targets to set.
Issue raisedNABERS Energy – All

Does not provide adequate ratings for buildings that are significantly more energy efficiency than a 5 star rating.  (Although scale has recently been extended to 6 stars).

Suggested fixExpand the star rating scale to 7 or 8 stars.
CommentInsufficient driver for organisations to improve performance above 5 stars.
CommentWe do not know if the rating will pass until we know which level 1 auditor receives our rating application.

Star increments

Issue raisedIncremental increases in building performance are not rewarded under current full or half star rating, a 0.25 star improvement should be acknowledged.
Suggested fixIntroduce .25 star increments.
CommentCurrent system does not encourage incremental improvement. We all know this is how it works, sometimes over long periods.

Fractional positions between star rating thresholds

Issue raisedFor those of us working with the tool as a key professional tool, it is essential to be able to understand the position of a rating between the official rating thresholds.  This has become progressively more difficult with upgrades of the NABERS calculator which have, if anything moved to make it harder to determine.
Suggested fixThe rating calculator needs to be updated to include a calculation of fractional rating to 2 decimal places (or at least 1.5 decimal places) to provide a consistent and unambiguous basis for comparison.  This figure should not be published on the rating certificate, but should be available from the calculator to provide a common language for tracking and monitoring purposes.
CommentIt is a significant waste of time for us and a significant confusing factor for industry, as there are several methods used to determine and express fractional positions between rating thresholds and these don’t always align. This problem is significantly worse since the introduction of the 6 star rating as it means that the slope is not constant.  We also have the ongoing confusing mythology in the industry that the decimal rating is the same as the calculated number from which the star rating is derived, when these are of course half a star different – a confusion which to some extent seems to exist at OEH, too.  The need to understand fractional ratings is a critical one for any organisation that tracks the performance of its buildings over time – which is a good deal of the industry.  It is also absolutely essential in the interpretation of simulation results for commitment agreements.
CommentA refinement to calculation tool to allow nomination of actual point score within star bands for more precise reporting and monitoring of property assets.  i.e. a 4.8 (4 star) result would hopefully provide a building owner with more incentive to reach 5 star at next opportunity

Building materials

Issue raisedNo NABERS material credits to assess sustainability of the final structure. As the ‘as occupied’ building tool, NABERS is in a position to ensure that materials specifications are adhered to by the contractors.  Currently inappropriate materials substitutions are rife.
Suggested fixIntroduce materials credits with life cycle assessment basis and physical verification required at certification.
CommentDeteriorates green building quality and value.

Thermal metering, electrical sub metering

Issue raisedNo specific issue with the tool or what it is trying to achieve.  What I have come across is a lack of knowledge – therefore referenced resources – in how to apply thermal metering and sub-metering.  Specific technical references that include schematics would be appreciated by the industry.  Skills shortages are a major issue.  Almost no competent programmers of smart meters in the NT.
Suggested fixThe cross-discipline techniques and schematics required to conduct effective sub (electrical) and thermal metering.  Far too many projects result in variations due to failure in design.
CommentLeads too excessive costs, poor monitoring, billing issues, poor evaluation.

Most recently on a building with NABERS commitments, the electrical spec did not match the hot water electrical requirements (hydraulic spec).  Same building requires complete rewiring of boards for all air conditioning.  Brand new building.

Issue raisedDifficulty with thermal metering, for NABERS Office Energy and Water.
Suggested fixReview of thermal metering protocol.

Meter accuracy

Issue raisedAccuracy of meters is no longer nominated.
Suggested fixNominate accuracy of meters.
CommentPossible to have inefficient meters, which is probably not what the NABERS team wants?  Confusion when it comes to validation.

Meter validation

Issue raisedOffice Energy / Water

The requirement for validation of gas and water meters linked to a RMRS is currently impossible to justify and fulfil as there are no agencies willing to validate the equipment.  Gas services must be shut down for validation (impossible in working environments) and no water manufacturer will confirm the accuracy of a meter after periods of time in use.

Suggested fixReview the concept of meter validation across these meters.
CommentCurrently we need to avoid use of any equipment in this category, or bluff our way through ratings.

Manual meter reading

Issue raisedAll tools

Gas and water manual readings.  Currently retailers only need to provide accurate readings twice per year.  This does not suit NABERS.  We use manual readings to obtain up to date data. The Rules that NABERS use seem to vary depending on the auditor and a new ruling that must be complied with……. however it has not been released yet.

Suggested fixAn official ruling – however with the input of actual NABERS assessors who are completing the ratings that have an understanding of real life data situations.

Occupancy surveys

Issue raisedAll tools – Definition of occupancy surveys

Inconsistency in interpretation leading to inconsistency in ratings.

Suggested fixClearer definitions should be provided.
CommentInconsistency in interpretation leading to inconsistency in ratings.

Outdoor air control

Issue raisedWhole building – Office, Industrial, Shopping centres – Queensland

Outdoor air quantities especially with humidity as we get of north easterly winds and variances with people movement in Airports.  CO2 monitoring with high ceilings especially in airports as it would be lucky if monitoring is effective.

Suggested fixPresently we are having adjustable outside air control for people in transient for CO2 and reduced outside air control.

NABRES Tools should accommodate and recognise this control strategy.

CommentNABERS should establish a rating tool for airports.

NABERS and Green Star

Issue raisedShould be a comparative assessment between Green Star and NABERS
Suggested fixHave a comparison value E.G. if you have a Green Star rating of..?..  It should be equal to a NABERS rating of..?.
CommentThese ratings affect lease and property value

NABERS energy – benchmarking

Energy intensity/energy efficiency

Issue raisedThe NABERS Energy tool only focuses on carbon as a metrics. There should be also a focus on energy intensity and how we can incorporate that into current practice. There is an issue with energy shifting.  A lot of work in the market is currently based on shifting the energy from grid electricity to gas.  Whilst the emissions are lower, the dependency on fossil fuels is still there.
Suggested fixThere is an opportunity to drive energy and greenhouse gas reductions significantly.  There needs to be some incentive built into the NABERS rating to reward energy intensity that is resulted from pure energy efficiency rather than energy shifting.
CommentNABERS Energy has been used as a carbon accounting tool.  – Emphasis is only on greenhouse gas emission reduction and not necessarily on energy efficiency.  –This leads to energy shifting as opposed to energy efficiency.
Issue raisedStar rating is based on fuel source, rather than energy efficiency.
Suggested fixCarbon emissions can still be reported, but star rating should be based on energy use of the building, and not on the emission intensity of the source fuel.
CommentBrown coal source of primary fuel (in Victoria) should have no influence on the energy performance of the building
Issue raisedNABERS energy is emissions based rather than energy efficiency based
Suggested fixRevert to a purer energy efficiency tool as the base measure.  Deal with energy sources as a secondary test, similar to current treatment of Green power.
CommentCurrently tools encourage co- and tri-gen, which may not be the most overall efficient outcome, i.e. lots of small generators, rather than one large generator, increases inner city pollution levels rather than locating them away from population sources.  Penalises Victorian buildings using electricity centrally generated, but not gas used at the site, so increases push to localised gas based energy production
CommentNABERS needs to strongly consider whether it wants to remain carbon efficiency or energy efficiency focused.  At present, we could have a highly energy efficient building, and a less energy efficient building with a co-gen system attached to it rating at the same level.
CommentGiven the rise in on-site generation (co/tri-gen, solar, wind etc.) and off-site renewables we are muddying the water by remaining focused on emissions.  We shouldn’t ignore emissions but perhaps a better outcome for the industry is to focus on energy efficiency as the central tenet of the tool and report emissions only.

Format and benchmarks

Issue raisedNABERS Energy for Offices – Base/whole building

The tool is in an outdated format that needs to be aligned with the format of all the other tools, i.e. site-adapted benchmarks rather than normalised emissions.  This will enable integration of the tool into a multi-type building benchmark and will also enable better resolution of existing normalisation work-arounds in high star rating regions.

Suggested fixI think what is required is a first principles re-benchmarking and redevelopment of the system.  This needs to commence with a data collection/collation exercise based on modern data to enable review of benchmarks. This can then be integrated into a single national benchmark with state variants based solely on greenhouse coefficients and climate zones rather than the current system of separate state benchmarks.
CommentThe existing tool is getting very dog-eared and has been patched up a little too often – not surprising for a tool of its age.  As a result it is beginning to seem a little ad-hoc in the methodology department.  A return to a simpler and more fundamentally appropriate approach will remove the patches.  The most obvious problem here is the lack of consistency in benchmarks across state boundaries.
Issue raisedNABERS Energy – tenancy / whole building

The tenancy tool benchmark needs to be re-evaluated.  With the increase in energy efficiency of new computers and office equipment, the market seems to have moved quite significantly.

Suggested fixA review of the benchmarks will provide the industry with better understanding of how their tenancy/whole building rates compared to others.  This will drive new energy efficiency and lead to the industry constantly aiming to improve.
CommentNABERS Energy for whole buildings and tenancies is shifting the star ratings quite significantly. It can be argued that the average 2.5 Star does not apply anymore and the market has moved on quite significantly.
Issue raisedNABERS Energy for offices – tenancy

Benchmarks are inconsistent from state to state.

Suggested fixSingle set of consistent tenancy rating bands needs to be developed in coordination with redevelopment of base building/whole building tools.
CommentTenancy ratings for identical tenancies vary by as much as 2 stars.
CommentPlease publish the latest benchmarks for the new 5.5 to 6 star rating scheme.

Transparency and normalisation

Issue raisedThe NABERS Energy tool has never been released to the industry to understand how it is calculated and how the variables actually impact a building.
Suggested fixAbsolute transparency is required such that building owners/facility managers/consultants can inform themselves of the best way to improve their NABERS ratings.
CommentWithout the available knowledge and transparency building owners and consultants are committing to building upgrades to meet desired NABERS ratings. This may have issues in terms of over commitment/under commitment. Furthermore it does not assist the rating going forward as there will be assumptions made by each consultant that cannot be verified.
Issue raisedThe calculation scheme needs to be more transparent such that the industry can understand the rating system and work towards increasing their sustainable aspirations.
Suggested fixMore transparency is needed for the industry. The rating calculation should be made public.  A review of the calculation should be made to understand whether the assumptions made are still relevant.
CommentLack of transparency will lead to a less informed user/building owner.
Issue raisedNeeds to be completely transparent.  Conversion of energy factors from state to state need detailed explanation as to why the differences.
Suggested fixReleasing the relevant calculations and decision making process that occurred in order to develop the tool to current state.
CommentLack of transparency leads to a lack of trust in the tools.
Issue raisedNABERS Energy for Offices – Tasmania

Lower figure utilised for CO2 within Tasmania significantly hampers the performance of buildings in Tasmania compared to the rest of the country, at times, a mainland location can be emitting 3 times the carbon equivalent and get a better rating than an equivalent building in Tasmania.

Suggested fixUse standardised carbon outputs, not adjusted to suit the bigger States.
CommentMakes Tasmanian Buildings look less efficient than other areas.
Issue raisedNABERS energy for offices – base bldg.

I think this is a simple though robust way to provide ratings for building.  I would like to see more transparency on the methods used to normalise ratings.

Suggested fixProvide more transparency on the methods used to normalise ratings.
CommentWould provide clarity for assessors.
Issue raisedThe rating has recently been extended to 5.5 & 6 stars.  However above 5 stars the rating result does not state the benchmarking factor as above 5 stars the rating is now determined based on the percentage reduction of emission from the 5 star building.  These emissions figures are not available.
Suggested fixIf the emissions that the building would produce at 5 stars was provided in the “For NABERS assessors” section of the rating result this could be used to determine the percentage reduction from the 5 star rating.
CommentNot having these emissions figures means that it is not possible to determine how close a building is to the next star rating band.  It also makes it much more difficult to determine what improvements could be made which would improve the building up to the next rating band.
Issue raisedNABERS not consistent across the nation – The basis of the NABERS rating is not transparent
Suggested fixNABERS transparency – Conversion of energy factors from state to state need detailed explanation.

GHG emissions

Issue raisedStar Ratings give little information to a prospective tenant about likely GHG emissions or energy costs.
Suggested fixThere needs to be a web-based translation tool that converts the Star Rating back into GHG emissions and energy cost (demand and energy at a typical tariff).
CommentProspective tenants cannot extract useful information from the Star Rating like GHG emissions and energy costs.

Maximum demand

Issue raisedThere is no accounting for maximum demand in the rating, which can be a major part of power costs.
Suggested fixThe Star Rating could be translated into Energy and Demand-related dollars (ballpark numbers at a nominated tariff) so that expected energy costs could be predicted in the new location by a prospective tenant.
CommentProspective tenants need to know if the previous tenant were wasteful or frugal and if there was active demand management or a free-for-all approach to maximum demand.

Green power

Issue raisedPurchase of excessive % of Green Energy can distort NABERS rating.
Suggested fixIntroduce a 3 year sliding scale limit (20% – 15% – 10%) to the amount of Green Energy, with the proviso that the sliding scale could be negated by an owner’s proven Capital expenditure on energy/water/waste sustainability projects.
CommentThe purchase of a large percentage of Green Energy can be used as cheaper economic tool for building owners to achieve a better NABERS rating rather than commitment to actual capital improvements to improve the sustainability of their buildings.

Sliding scale

Issue raisedNABERS officeused to have a sliding scale that indicated where your building fell in the scale and showed the relative benchmarks for adjacent star levels that enabled easy analysis of what a building owner could do to improve their rating
Suggested fixAdd back in the scale
CommentReduced opportunity to inform clients of how much effort required to improve a building facility


Issue raisedThe current metrics is based on real estate terms that don’t evaluate a holistic sustainability approach.

The base building tool does not allow for any allowance when it comes to the size of the tenancies.  This has led to the tool being used as a divider between tenants and base building owners.  There are now restrictions on tenants for the number of staff/m2 that are allowed.  This means that dense tenancies need to invest in getting more buildings built leading to a higher embodied energy use.

Suggested fixA review of the impact of tenancy size on the base building NABERS rating is needed.  This needs to be accounted for in the rating to provide a level benchmark and lead to a more holistic approach.

Whole building/base building ratings

Issue raisedThere is no correlation between whole building and base building ratings.  The two ratings simply do not relate – doing a rating on base building and then on whole building due to a minor infraction of the Rules causes a significant difference in the published star rating that then has to be used in public advertising.
Suggested fixRevise the whole building tool to better reflect the base building rating.

NABERS energy – general application

Scope of assessment

Issue raisedNot enough examples when it comes to defining the scope.

There’s a great deal of confusion when it comes to establishing the proper spatial/time/coverage of the assessment.

Suggested fixI would prefer if the manual had more examples for each type of exclusions/inclusions to assist with clearly defining the scope of the assessment and not have any grey areas.

Required documentation

Issue raisedNABERS energy for offices.

The documentation requirements for the tool are unclear.  The checklist of ‘information’ and sections in the Rules on “Documentation Required” is vague.  For example it is common that for a Base Building rating, every tenant and base building electrical distribution board must be inspected and photographed to ensure that the systems connected to these boards are connected correctly.  In addition it is often necessary to obtain schematics of the tenant heating hot water and chilled water loops/systems and a schedule of all supplementary systems and the areas they serve, to justify their inclusion/exclusion in the rating.  This is not reflected in the checklist provided in the Rules and it should be.

Suggested fixA detailed and complete checklist of required information should be included in the Rules, with simple prompts to ensure the assessor knows when to ask for the information.  The assessor should be able to be very confident that once they have obtained all of the information on the checklist, they will be able to submit the rating with no issues.
CommentCurrently accredited assessors gradually learn what is ACTUALLY required for a NABERS rating, often via trial and error and under instruction during the supervised ratings.  Often this leads to several site inspections being required, and multiple requests for information to the client.

Ambient temperature

Issue raisedAlthough NABERS takes into account different climate zones, it doesn’t take into account the fact that temperature varies each year.  For example, for a given location, the ambient temperature (a major factor in commercial building energy use) varies each year.
Suggested fixThe ratings could be normalised for ambient temperature not just climate zone
CommentIf the rating period includes a hot summer then a building may receive a worse rating that it would if it was a cool summer.

Information and communication technology

Issue raisedWhole building

Differentiation of energy use and carbon output of ICT within offices tenancies and buildings.  Imprecise calculation method for computers.

Suggested fixMeasurement by precise equipment monitoring technology.
CommentInability to quantify and measure carbon of ICT and monitor carbon effect on IEQ.  8 billion computers now to grow to 20 billion by 2020.

Previous tenant history

Issue raisedLandlords and building owners get penalised for the poor energy efficiency of previous tenants.  There may need to be some general explanation about how the previous tenant used the space: occupancy, thermostat settings, maintenance issues, light levels etc. so that a prospective future tenant can gauge the relative strength of the Star Rating to their proposed use.  Otherwise the Star Rating will be of little use to a future tenant – it won’t indicate more or less energy consumption for their proposed use.
Suggested fixInclude a general explanation about how the (previous) tenant used the space in the rating report.
CommentLandlords are not able to change the history of a previous wasteful tenant but also gain from the energy efficiency (higher Star Rating) of a frugal tenant.

NABERS energy – building types/space types

Old/heritage buildings

Issue raisedNABERS Office – Whole Building

Non-practical minimum functional space requirement for old/heritage buildings, where you have multiple physically separated areas due to the building structure, but do not meet the minimum functional space requirements.

Suggested fixReview minimum functional space requirements for old/heritage buildings.
CommentOld/heritage buildings sometimes difficult to comply.

Owner occupied buildings

Issue raisedNet lettable area is an issue when the whole building is owner occupied.
Suggested fixHave standard ratings/energy consumption for different areas so they can be excluded from the calculations.
CommentSub meters need to be installed so like comparisons can be made with appropriate ratings.

Site inspections/as-installed data

Issue raisedThe tool is not clear on how to deal with large sites with multiple buildings sharing common facilities such as basement carparks or large mixed use buildings.  There also does not seem to be an easy way to deal with older sites where circuits are not clearly labelled and as built information is typically missing so it becomes difficult to determine what services are connected where.
Suggested fixRaising industry awareness about the importance of As Built information and how services are required to be connected, regardless of leasing provisions.
CommentIt can make the site inspection process take a very long time as buildings have to be surveyed to determine what equipment is connected to which switchboard

Multi-use office buildings

Issue raisedThe NABERS energy for office tool clearly states that the tool is for office buildings.  The term office is clearly defined.  However, the rating tool does not appear to specifically state the how much of a building’s NLA needs to be used as “office” in order to qualify for an accredited rating under the NABERS energy for office tool.
Suggested fixProvide a clear percentage and ruling of a building’s NLA or total area that will need to be used as office space in order to allow an accredited base building rating using NABERS energy for offices.
CommentIt is currently not clear if a mixed-use building that may have a large component of commercial office space but still accommodates a reasonable percentage of retail, residential or public space use can be rated under the NABERSEnergy for Offices tool.

Permitted space types

Issue raisedWith CBD, NABERS has gone from being voluntary to mandatory, and I think that this makes it important that the tool aims for maximum flexibility in application. To this end I think it is important that the rules around the definition of allowable space-type inclusions are reviewed; after all we have allowed education and medical facilities, in limited quantities, to be included, so why not childcare (which I could argue is an education facility) and possibly some others in a similar low load vein?
Suggested fixA review needs to be undertaken of a range of generally low load tenancy types, and their potential impact in biasing the NABERS Base Building rating determined.  I note that when this was done for the issue of vacancy the simulations indicated that the issue of vacancy made very little difference to energy use for a base building system once the decision has been made to run rather than not run.  By inference therefore, for a wide range of applications with loads between normal office loads and zero, the impact on the base building rating is also going to be very small.
CommentPermitting a wider range of space types to be rateable – with suitable limits – would reduce the number of people making bad design decisions to achieve rateability ahead of common sense.  It would also increase the number of immediately rateable buildings

Foyers and premium grade buildings

Issue raisedNABERS energy for offices – base building

Premium office buildings are at a significant disadvantage because of extensive foyer space etc.  B grade offices have limited foyer space which benefits the rating significantly.

Suggested fixIntroduce concessions for foyer space over a certain m2.
CommentPremium office spaces are at a disadvantage even though the buildings systems may be very efficient.

Corridor treatment

Issue raisedNABERS energy for whole building – Corridor square metre area measurement not included
Suggested fixInclude all common area corridors.
CommentDistorts the amount of “Common Area” used in calculations; note that Corridor Common Area(s) electrical lighting is included in the Energy bills for the building.

Tenant toilets

Issue raisedOffice Base Building – non-office spaces – tenant toilets

Exclusion of tenant toilets from NABERS area requires non-industry standard area calculations to be completed for the assessment increasing cost and time for no obvious benefit.

Suggested fixWhile not air conditioned specifically, toilets are exhausted typically via an extension to the base building system.  Any reduction in air conditioning loads for a 15m2 toilet and shower combo is minor and may be offset by increased toilet exhaust fan energy.  It is hard to imagine that tenant toilets generate an impact on base building energy any different to tenant storage cupboards, kitchenettes or compactus.

NABERS eEnergy – occupancy and activities

Building vacancies

Issue raisedNABERSEnergy for Offices – The massive penalty that comes from building vacancy rates.

NABERS ratings change from year to year, there is no real comparison between buildings, and thevacancy penalty causes a building to be less attractive in the market resulting in less attractive leasees.

Suggested fixInclude vacant areas in assessments.
CommentNote vacancy rate on rating.

Building design occupancy

Issue raisedNABERS Energy for Offices does not take into account the design occupancy of the building. To obtain better ratings some new “green” buildings are being designed for occupancy of 1 person per 15 or 18 m2.  The tenant is then forced to install supplementary units where the occupancy exceeds this.  This is in effect transferring some of the air conditioning duty from efficient base building systems to inefficient supplementary units, a retrograde step.  It is also resulting in tenants in these “green” building obtaining poor NABERS Energy Tenancy ratings even though they have efficient lighting systems and sophisticated lighting controls.
Suggested fixThe NABERS rating rules should stipulate that the building be designed for the standard BCA occupancy rate of 1 person per 10 square metres and include a penalty for designers that wish to differ from this.
CommentThis issue is distorting the results of the rating system and tarnishing the NABERS reputation.

Hours of occupancy

Issue raisedHours of Service are rarely put into leases as required by the NABERS protocol.
Suggested fixTrust the assessor to properly determine what the start and stop times are without any further penalty.
CommentThe requirement to subtract 2 hours from what is seen on BMS logs does not accurately reflect true usage and can make ratings poorer than they actually are.
Issue raisedNABERS Energy for Offices – Base Building

The perceived priority to have a Tenant Occupant Survey undertaken for a base building rating for the normal hours of use, as opposed to using the lease documents that indicate normal hours of use.  The requirement for leases to specifically state that “the space will be safe, lit and comfortable for office work”.  Most current leases that have been in place for many years state the “normal office hours” for the lease period which means that the building is safe, lit and comfortable for office work.

Suggested fixThe priority for the base building hours of operation should be:

  1. What the lease document states for “normal office hours” or what are considered to be “after-hours” or if the lease states the hours for which the space must be safe, lit and comfortable for office work.
  2. Written amendments to the lease document signed by both parties.
  3. Tenant Occupant Survey information.
  4. Evidence of plant operation less 2 hours per day.
CommentUndertaking a client survey adds unnecessary time to undertaking a NABERS base building rating and the results of tenant surveys are unreliable due to the people asked to complete them generally providing generic information rather than the specific information for the space they manage.
Issue raisedNABERS Energy for Offices – Base Building – Classification of “core building hours” in a lease agreement – leases are written in many different ways and the Rules are not clear enough regarding the wording required to comply.
Suggested fixMore information/examples of how “core hours” must be defined in the lease agreement.
CommentOften results in extensive debate between assessor and reviewer regarding wording of lease, with the Rules not being definitive enough to settle the dispute.
Issue raisedNABERS Energy for Offices – Hours of occupancy.  The requirements for the hours of occupancy demand that leases must denote the agreed hours “the building is safe, lit and comfortable for office work”.  I have not yet encountered a lease with similar phrasing therefore tenant occupancy surveys must be used.  In many cases the tenants do not afford any time or thought in completing the surveys (if return at all).
Suggested fixAcceptance of the normal hours of service noted in leases.
CommentBy my experience the current situation leads to a reduction of the actual hours the building operates and adds unnecessary delays and cost to rating buildings.
Issue raisedNABERS Energy for Offices -The tool is not flexible with hours of operation.  Most multi-floor buildings need to have tenancy floor temperatures available at occupancy lease time schedules.  I believe NABERS does not allow additional run time to either cool or heat for morning occupation times.
Suggested fixMost Building Automation systems factor in “Optimal Start Times Logic” to monitor out of normal office floor space average temperatures and calculate plant start times.  I believe the normalized office hours used for calculations should include additional plant running hours percentage.  Our tenants expect and demand environmental limits to be achieved and maintained irrespective of changing seasonal parameters.

Alter process matrix to incorporate additional plant running times.

Issue raisedNABERS Energy for Offices – tenancy and whole building

Documentation when conducting random interview staff to determine hours – Rules do not state that a survey form must be completed, however the reviewer required one and said that not having one would fail an audit.

Suggested fixClarify documentation requirements for Alternative Methods for verifying hours of occupation.
CommentPotential for assessor to fail audit for a reason not clearly stated in the rules.
Issue raisedRated hours – If the lease does not specify comfort conditions, the assessor takes 1 hour off at the beginning of the day and 1 hour off at the end of the which results in a deduction of 10 hours per week for the whole building.  I understand that it takes time to bring the building to comfort conditions in the morning, but at the end of the day the building will maintain conditions even after the HVAC is turned off.
Suggested fixRemoving 1 hour at the beginning of the day is understandable, but taking 1 hour off at the end doesn’t seem right.  I would amend this by only taking off 1 hour in the morning if the lease does not state comfort conditions.
CommentReduction in hours per week negatively impacts on the rating.
Issue raisedBase building ratings on buildings with whole building ratings may be forced to use the tenancy occupancy survey hours of operation which are invariably less than those gained from BMCS afterhours request data.
Suggested fixChange in priority for hours of operation for base building ratings so that leases hours + BMCS logged after hours data is top priority.
CommentReduced ratings or inability to get ratings.
Issue raisedThe weighting given to tenant use rather than building efficiency.
Suggested fixBuildings rated on standard hours rather than on hours operated.
CommentEfficient buildings or non-efficient buildings are downgraded due to tenant use rather than the efficiency of the base building.

Definition of office/clerical activities

Issue raisedOffice Base Building – non-office tenant operations on office floors.

NABERS should consider expanding definition of office/clerical type activities to allow for non-clerical activities that are conducted with similar lighting, equipment and usage schedules.

Suggested fixWiden definition of office clerical to a functional requirement i.e. lighting and equipment load W/ m2 and usage schedule information from BCA or AS1668.2 same as office (+/-25% say) then equivalent to office.
Issue raisedNABERS Office – Whole Building

Non clear classification for areas that are fully lit and air conditioned as an office space such as Australia Post Mail Sorting area.  It is unclear whether this can be classified as an office space or not, i.e. if mail sorting is considered as a clerical type of work.

Suggested fixImprove the office space classification/definition to include broader range of work type not only specifically clerical as long as the areas are defined as NLA, and fully air conditioned and lit comparably to an office space.
CommentCurrent classification disadvantages many buildings such as Australia Post GPOs where the ground floor is used mainly as mail sorting areas.  These areas are already disadvantaged by the fact that there are no computers, and if not sub metered you will have an entire floor that is fully serviced by the base building with excluded area.

NABERS energy – systems

Supplementary systems

Issue raisedAllocating the energy of supplementary systems is currently unclear.  The definitions of a system that is a tenant supplementary system versus a system that has been installed by the Base Building are unclear.  Only definition includes the phrases “generic service” and “custom service” however there is no definition for either of these terms.
Suggested fixVery clear definitions of what is and is not to be included under each rating need to be given.  The handful of vague examples provided in the current Rules falls significantly short of allowing many common scenarios to be easily classified.
CommentHuge variations in the NABERS rating of a building may occur depending on how the Rules are interpreted. For example in the event that it is determined that a supplementary tenant system is to be allocated to the Base Building and this system has insufficient sub-metering, ALL of the tenant energy must be allocated to the rating. In an example that I have encountered, the tenant energy consumption is more than that of the base building due to the tenant having many large computer rooms. The rating would change from 4.5/5 stars in this case to potentially 0 stars. Only one rating really represents the Base Building energy performance, however, the ambiguity in definitions severely compromises the supposed robustness and repeatability of the NABERS rating scheme.
Issue raisedNABERS tenancy

Clearer definition/allocation of base building and tenant supplementary air conditioning systems

Suggested fixClear examples of where tenancy supplementary air conditioning units fall into the base building energy consumption assessment.
CommentDefining what falls into the base building and/or tenant’s assessment ratings can have a big impact on the rating result.

Tennant chilled water/Rule B2

Issue raisedOne rule under Energy Coverage precludes the use of Supplementary Tenant Chilled Water.  Rule B2 attributes energy used in supplementary tenant condenser water and chilled water as a base building item.  This is understandable for supplementary tenant condenser water (because the majority of energy is from the tenant metered boards i.e. water sourced packaged units).  However this form of cooling (cooling towers / water sourced packaged units) is inefficient when compared to providing direct chilled water to the tenant.

By favouring condenser water over chilled water the rules tend to perpetuate an inefficient system.

Suggested fixThe solution is fairly simple: The tenant energy use can be metered directly and all energy use can be apportioned to the tenant.
CommentA rule change to allow for chilled water to be used (for supplementary cooling) and directly meter the energy use.
Issue raisedTenant installations or requests for installations make a base building rating worse.  The main example is that a tenant’s chilled water loop is installed in addition to a tenant’s condenser water loop at the request of the tenant.  This energy is therefore a tenant energy use but the base building is penalised when compared to other buildings.
Suggested fixWhere a condenser water loop and a chilled water loop are available for the tenant use the energy from the chilled water loop should not be included in the base building rating.
CommentNABERS Energy Rule B2
Issue raisedOffice Base Building – CHW Exclusion.

CHW exclusion requirements should be updated for current technology and also clarified.

Suggested fixCHW exclusion document is excellent but needs to be updated.

Estimating small thermal loads

Issue raisedNABERS energy for offices

Apportionment of thermal energy use and / or estimation of small uses

Unfairly increases emissions to buildings where a small thermal use like hot water is taken from an adjacent, larger and more efficient system.

Suggested fixInclude more flexibility in allowing assessors to put forward methods of apportioning thermal energy based on sub-metering and / or accurate estimations if they can be proven to be sufficiently accurate.

Gas calculations

Issue raisedGas Exclusion calculations – Gas Tab: The ‘Energy consumption in period’ is currently calculated as the multiplication of both the energy content factor and the pressure conversion factor.  This is effectively ‘double dipping’ the energy calculation.  I have correspondence from OEH that this is an error in the sheet.  If needed I can forward this correspondence on to you.
Suggested fixChange in formula.
CommentCurrent calculation results in over calculation of gas energy exclusions.
Issue raisedThe requirement to include a gas meter correction factor along with the gas heating value for gas bills can potentially skew sub meter data.  This is due to the fact that for sub meter data you also apply a correction factor, but it takes into account the utility meter correction factor already.  In most cases this won’t cause serious issues, since typical meter correction factors are 1.02 etc., but for any larger (higher pressure) meters, you can have factors of around 2.0.  This would then over report non-utility gas use by a factor of approximately 2.
Suggested fixSimple fix within the spreadsheet
CommentPotential to incorrectly report on sub metered gas use.

Treatment of cogeneration

Issue raisedNABERS Energy for Offices

Inability to apportion emissions for cogeneration system based on heat use.

If a part of a building gets benefit from the heat, but not the power, it still can’t be apportioned any of the emissions.  The user of the power gets the penalty of the emissions.

Suggested fixCreate a strategy for apportioning the emissions of a cogeneration system which splits it between the waste heat used and the power used.
CommentTrigeneration also.

Diesel readings

Issue raisedRequirement for 2 diesel readings per annum.
Suggested fixTrust what the building manager says.
CommentWhen only one or no reading is made you need to add full tank capacity to the assessment.

NABERS energy – data rooms/server rooms

Issue raisedNABERSEnergy for Offices – base building – The inclusion of data rooms – a tenant constructed, wholly tenant operated and controlled server room must be included in the base building under the current rules.
Suggested fixIf server room can be proved to be solely used by a single tenant and was not constructed for base building, energy and AC associated with this room should be allocated to the tenant, not the base building.
CommentCurrent situation has an unfair impact on the building owner/manager due to energy consumption outside their area of control
Issue raisedNABERSEnergy for Offices – base building – Energy consumption in a tenant space where the tenant has removed the base building conditioning equipment and installed their own equipment to service a special load or area, such as a tenant modifying the internal layout of a tenancy and installing a server room, removing the heating/cooling system within this space and installing a cooling only system to service this space.  This means the space is now not suitable for office space, however, as the tenant removed the existing heating/cooling, the new cooling only system must be regarded as the base building air conditioning for energy coverage.
Suggested fixPossibly calculate daily load for a normal office space (based on some W/m2 figure or based on dividing the AC consumption by the office area to get a w/ m2, then multiply by area and occupancy to get a kWh/annum result) and use this as the base building energy consumption for the space, exclude the rest as tenancy energy.
CommentIn this “real world” scenario the Server AC operates all times, reducing the final NABERS result for a base building when the building owner is not responsible for the energy use within a tenant area.
Issue raisedNABERS tenancy – How to estimate energy consumption of server rooms within tenancy for prediction of performance required for commitment agreement.
Suggested fixBetter server energy consumption model based on experimental data to be specified in the energy simulation estimation guideline.
CommentLow NABERS rating for tenancies with large data/server/comms room.
Issue raisedNABERS Energy for offices – tenancy

Data Centre energy use may be excluded if it serves users outside the building, however in no tool does the end user need to add in energy they consume from remote data centres.  In this way people are encouraged to locate their data centre storage offsite (which may not be a bad thing), and the energy is not attributed to anyone.  There is a severe penalty to offices with a data centre located on site if it serves their building as they must include the energy in their rating.

Suggested fixEither computer room energy is always excluded regardless of who it serves, or users must identify any computer facility serving their tenancy and obtain an allocation of the facility’s energy use as a percentage of how much of the facility is used by them.
CommentSome buildings are severely disadvantaged.  In theory it would be possible for two adjacent buildings to agree to house a data centre / computer room for each other within their tenancy and each exclude the energy as it is not serving their own building.

NABERSEnergy – Commitment agreements

Harmonise energy modelling protocols

Issue raisedNABERSOffices – Commitment agreement.

Uniformity with BCA and Green Star; all 3 tools need to rationalized in terms of scheduling, occupancy rates, metabolic rates etc.

Suggested fixHarmonise energy modelling protocols
CommentCurrently causes confusion and unnecessary rework.
NoteOngoing project with OEH NSW, GBCA, ABCB, AIRAH, IBPSA, DCCEE.

Project feedback

Issue raisedThe inconsistency between modelling protocols for Green Star, NABERS, and JV3 creates problems and inaccuracies. Better matching of the protocols to the NABERS rating is required via feedback from projects that are modelled.
Suggested fixCo-ordinated feedback loop built into the commitment agreement between energy modelling and NABERS rating.  Wording within the commitment agreement such that there is a grace period for which the building must be tuned to allow systems to be optimised to meet the energy target of the agreement.
CommentCreates inconsistency and inaccuracies in the modelling outputs and hence commercial risk associated with NABERS commitment agreements.  This is a serious PI insurance risk and a real issue for our insurers.

Relationship with BCA

Issue raisedThe BCA should use the precommitmentagreement as an alternative solution.
Suggested fixModification of BCA.
CommentBCA approvals.

NABERS retail

Validation of central services

Issue raisedNABERS Shopping centres – The process of validation the central services across each ‘zone’ is extremely time consuming and makes the job almost impossible to price.  We audited centres >100,000sqm and found the process extremely difficult and a deterrent to completing the rating.
Suggested fixDevelop a new way of reviewing the buildings.
CommentOur client is unlikely to complete the ratings again until it is mandatory.
Issue raisedThe non-consideration of trading hours particularly in how it disadvantages shopping centres where centrally services HVAC is provided to stores that have late trading hours or are 24/7.  This is actually a perverse outcome because there is s move towards centrally serviced water cooled chilled water HVAC systems away for air cooled PAC units because of the overall greater energy efficiencies of these systems by comparison.
Suggested fixConsider trading hours in the NABERS calculator.  As part of the NABERS Retail Technical Advisory Group, I am aware of the efforts to resolve this issue.  The problem is with small benchmarking sample size which does not provide statistically significant data to say this is an issue. There is a fix proposed, but it is taking a long time to resolve with OEH.
CommentNABERS Retail Energy/Water – Lower rating result.


Issue raisedNABERS Retail Energy and Water

Tool doesn’t allow for correct allocation of energy and water between base building and tenancy.

Suggested fixUse the principles set in office protocol for retail.
CommentNABERS Ratings don’t currently reflect the performance of the property.

NABER hotels

Conference catering

Issue raisedNABERS energy and water for hotels – whole building

When off-site catering is used to service the conference facilities then the star rating of the hotel is unfairly disadvantaged.

Suggested fixA standardised energy usage based on number of attendees should be used when the energy cannot be measured.
CommentCurrently the resulting star rating is not representative of the hotel.

Serviced apartments

Issue raisedThe NABERS Hotel tool ignored serviced apartments which are a major part of the hotel scene in Australia – Simply stupid or in the too hard basket?
Suggested fixAdd serviced apartments in to rating tool.
CommentA large part of the market is missed out and therefore not influenced to change by this tool.

NABERS water

Integrated stewardship of water

Issue raisedThis tool does not go far enough to encourage integrated stewardship of water.

We do not consider value of water as it integrates with the whole building.  This includes the embodied water of items, embodied energy of water and allied resources like nutrients.  Also no thought is given to GHG emissions from waste water.

Suggested fixDevelop meaningful metrics to addressintegrated stewardship of water.

Water and population

Issue raisedWater usage is highly dependent on population but the NABERS water tool does not take into account population density of a building, i.e. a low density population (1 person/15 m2) will more easily obtain a higher rating than a higher density building (1 person/10 m2).
Suggested fixAdd in a population factor as is done with the Energy tool to allow for greater density populations.
CommentCurrent arrangement encourages design of lower population density buildings which will also affect energy consumption etc.

Manual meter readings

Issue raisedOften water ratings need to include a manual meter reading by the assessor as the utilities usually provide only quarterly billing.  The water usage (e.g. in a final rating period reading) is taken from the previous utility reading to the assessors reading irrespective of the end date of the rating period with no pro-rata consumption considered.
Suggested fixAllow pro-rata water consumption for periods using manual readings from an acceptable utility water meter(s).
CommentThe actual reading by the assessor can sometimes be substantially offset from the end of the rating period and include an unrealistically increased usage, distorting the rating result.


Issue raisedNeed the ability to estimate water uses as sometimes water uses aren’t metered.
Suggested fixAllow for some estimation.
CommentWe used Green Star water tool as we were unable to do an official NABERS rating.

Sustainability strategies/shower water use

Issue raisedOther building sustainable strategies such as encouraging people to cycle to work through providing cycle storage and shower facilities is not taken into account in the NABERS rating system.  The provision of showers increases water usage of the building making it difficult to achieve good NABERS ratings.
Suggested fixProvide an allowance of water for this initiative in the rating process (as Green Star does).
CommentCurrently, designers wanting to achieve high NABERS ratings will not provide shower facilities for cyclists thereby deterring cyclists from riding to work.

Water for hotels

Issue raisedSome hotels have pools, laundry, irrigation, cooling towers and others have only some or none of these
CommentThis impacts the amount of water used per square meter

NABERS indoor environment

General comments on NABERS IE

Comment(NABERS is a) Globally leading rating system which needs to move into IEQ to ensure this significant area of future impact is not clouded by a mix of IEQ systems which are driven by commercial interests and not the best outcomes for all stakeholders.
CommentNABERS Indoor Environment is an excellent initiative and should be praised in the industry. The Indoor Environment is a very complex system, and rating this even more so. However, this must not preclude us (and AIRAH) as an industry in endeavouring to rate the most important influence on occupants and their productivity….the indoor environment.

Industry profile for tool

Issue raisedThis NABERS IE tool is not supported and promoted enough in industry.
Suggested fixProvide funding for education.
CommentImpacts on the ability to engage with occupiers on the benefits of good environmental upgrades and productivity in the workplace.

Interpretation of results

Issue raisedNABERS IE result is not clear; the tool cannot be interpreted by anyone.
Suggested fixDevelop a better tool.
CommentCurrent tool cannot be interpreted by anyone.


Issue raisedNote that the weightings for the NABERS IE tool should be revised regularly and changed when new research within the scientific community reflect such a change.
Suggested fixRevise weighting regularly.

Ventilation measurement

Issue raisedAir / natural ventilation measuring protocol – the specified equipment is for external wind measurement not internal.
Suggested fixSpecify appropriate equipment.

Mixed mode ventilation

Issue raisedAbility to integrate mixed mode types – some buildings have closed, natural vent only, and mixed modes.
Suggested fixMay be integratingtwo sheets into one rating.
CommentWe had to do two ratings.

Ventilation effectiveness

Issue raisedVentilation effectiveness assessment (using Carbon Dioxide as an indicator) is not scaled correctly.
Suggested fixThe points scaling should be altered to reflect current international knowledge and other rating tools in the industry (such as Green Star).
CommentCurrent rules result in buildings with poor to moderate ventilation effectiveness (as measured using carbon dioxide) achieving maximum points in this category.

Thermal comfort

Issue raisedThermal Comfort rating methodology is too simplistic or too coarse and will result in most buildings achieving full points.
Suggested fixIncrease the scope of Thermal Comfort testing to include more reference to ISO 7726 and ISO 7730 – International Standard for Measuring and Assessing Thermal Comfort.
CommentThermal comfort is not assessed correctly.  This will result in most buildings achieving full points.  It is also difficult to assess the NABERS Performance against standard design metrics such as PMV and PPD.

Airborne microbiologicalSampling

Issue raisedAirborne microbiological rating methodology is flawed.

The IEQ rating of the building can change by 0.5 to 1 star through natural environmental variation.  Also there are some situations where good air quality (in terms of airborne microbial concentrations) is penalised.

Suggested fixEither withdraw microbiological testing from the Rating Tool….or review the relationship used to assess the airborne microbial levels.  The current method works up to a point (namely when outside air microbial concentrations are very low), and additional calculation is needed when these conditions apply.
CommentInconsistent ratings from current requirements.
Issue raisedIt is known that microbial levels can vary dramatically with changing environmental conditions or locations within the day.  As such it would be best to obtain multiple external microbial samples to obtain an averaged ‘outside’ result, thus reducing the error of external samples.
Suggested fixAs a means to reduce this error an external sample should be taken, which is then followed by all the internal samples and is finished with another external sample. However all microbial samples should be taken within a 1 hour time period as a means of reducing external variability. If all microbial measurements go over the 1 hour period then another external sample should be taken to account for and reduce external variability.

Analysis of microbial plates

Issue raisedCurrently on page 53 of the NABERS protocol its states that a NATA accredited laboratory is to analyse the microbial plates.  This is an added cost which could be avoided since the NABERS protocol does not require speciation of the mould/bacteria which is present.  All that is required for the NABERS IE is a cfu/m3 number and as such it is sufficient for a competent laboratory technician to count the sample.
Suggested fixIt is sufficient for a competent laboratory technician to count the sample.

Airborne mould sampling section

Issue raisedNABERS IEQ currently specify testing for cfu’s (Colony Forming Units) which is not the internationally accepted method of measuring mould in relation to IAQ.
Suggested fixThere are many experts who can provide more detailed advice on this subject but I think that NABERS need to engage one to get up to speed on it as it’s a fairly important issue.
CommentThe reason for this is that less than 30% of all mould spores are viable meaning that if you are culturing mould spores, what grows on a plate is not indicative of what is in the air that people are breathing in.  For species of mould that release toxins, all their spores whether viable or not release mycotoxins and it is therefore more important to know that TOTAL airborne mould spore counts.

Spores and mould fragments that release mycotoxins can both be measured by using spore traps.

Also, some mould spores will not start growing on certain cultures until after the standard 5 days in the lab and some of these are the most concerning in relation to occupant health.

All of this info and more can be referenced in the WHO guidelines for indoor air quality – dampness and mould -ISBN 978 92 890 4168 3.

Air sampling – formaldehyde, VOC and PVOC:

Issue raisedCurrently air sampling requirements for Formaldehyde, VOCs and PVOCs are limited to one technique, i.e. silica sorbent tubes for formaldehyde, charcoal tubes for VOCs and XAD-7 for PVOCs, and as such will limit the choice of laboratories which can analyse these tubes.

Current NABERS IE validation protocol limits the use of new advances in scientific equipment and techniques. In regards to air sampling for Formaldehyde, VOC and PVOC the most current advances are not being implemented. For example, XAD-2 (e.g. SKC 226-118) tubes can also be used for sampling of Formaldehyde and these have the added benefit that during transportation to the laboratory these tubes do not require refrigeration, whereas the use of silica tubes (e.g. SKC 226-119) requires refrigeration during transportation and should be analysed within 24 hours.

Suggested fixIn order to not limit the use of advances in sampling technology and analysis methods the protocol should be specifying the use of sampling and testing techniques which are recognised by NIOSH, OSHA. Analysis methods should be validated and performed within a NATA registered laboratory. NIOSH methods for sampling and analysing Formaldehyde, VOC and PVOC are listed below.
CommentMethod for Sampling and Analysis of Formaldehyde

NIOSH 2016:- Sampling – Cartridge containing silica gel coated with 2,4-dinitrophenylhydrazine.

Advantages: Method has a lower detection limit.

Disadvantages: Requires correct storage conditions (<5oC) for sample integrity during transport.

NIOSH 2541:-  Sampling – XAD-2 (10%, 2-(hydroxymethyl)piperidine)

Advantages: Samples storage can be at room temperature during transport.

Disadvantages: Method has a higher detection limit, but within the requirements of the NABERS protocol.

Method for Sampling and Analysis of VOCs

NIOSH 1500 (aliphatic hydrocarbons), NIOSH 1405 (alcohols combined), NIOSH 1501 (aromatic hydrocarbons):- Sampling – Tube containing coconut shell charcoal.

Method for Sampling and Analysis of aromatic PVOCs

NIOSH 2546 (phenols):- Sampling – Tube containing XAD-7.

Hand held field measuring equipment

Issue raisedHand held field equipment should be cost effectively attainable.  This requires equipment specifications for the measuring range, accuracy and resolution to be defined in the methodology which reflects current scientific equipment available on the market.  Note that the measuring range, accuracy and resolution stated in the NABERS protocol should be set as a minimum requirement and not as the absolute requirement.

Current equipment specifications are unattainable with equipment on the market due to very restrictive requirements.

Suggested fixThe equipment specifications as stated in the table below are for scientific indoor environment quality measuring equipment which is readily available in the market. Equipment specifications as stated below should form part of the NABERS protocol.

Hand held equipment should have a current calibration certificate showing that it has been calibrated to manufacturer’s instructions.

Type of Measurement Suggested Minimum NABERS Requirements
Measuring Range Accuracy (see note) Resolution
Temperature 10-40oC Accuracy is usually one tenth the resolution, therefore accuracy is not required to be stated. Note also that stating accuracy leads to compliance problems as accuracy decreases as you approach the limits of the instrument. 0.2oC
Relative Humidity 10-90% 1%
Carbon Monoxide 1-50ppm 0.5 ppm
Carbon Dioxide 100-5000ppm 5 ppm
Particulate Matter (PM10) 1-5 mg/m3 0.02 mg/m3
Air Speed 0.05-10m/s 0.02m/s
Light Levels 100-2000lux 1 lux
Sound Levels 35-100dBA 1dBA
Microbial 10-5000 cfu/m3 5 cfu/m3
Type of Measurement Suggested Minimum NABERS Requirements Measuring Range Accuracy (see note)Resolution Temperature10-40oCAccuracy is usually one tenth the resolution, therefore accuracy is not required to be stated. Note also that stating accuracy leads to compliance problems as accuracy decreases as you approach the limits of the instrument.0.2oCRelative Humidity10-90%1%Carbon Monoxide1-50ppm0.5 ppmCarbon Dioxide100-5000ppm5 ppmParticulate Matter (PM10)1-5 mg/m30.02 mg/m3Air Speed0.05-10m/s0.02m/sLight Levels100-2000lux1 luxSound Levels35-100dBA1dBAMicrobial10-5000 cfu/m35 cfu/m3
Type of Measurement Suggested Minimum NABERS Requirements
Measuring Range Accuracy (see note)Resolution
Temperature10-40oCAccuracy is usually one tenth the resolution, therefore accuracy is not required to be stated. Note also that stating accuracy leads to compliance problems as accuracy decreases as you approach the limits of the instrument.0.2oC
Relative Humidity10-90%1%
Carbon Monoxide1-50ppm0.5 ppm
Carbon Dioxide100-5000ppm5 ppm
Particulate Matter (PM10)1-5 mg/m30.02 mg/m3
Air Speed0.05-10m/s0.02m/s
Light Levels100-2000lux1 lux
Sound Levels35-100dBA1dBA
Microbial10-5000 cfu/m35 cfu/m3

Carbon monoxide

Issue raisedCurrently the Australian Standard criteria for air pollutants states within the National Air Quality Standards that carbon monoxide should not be above 9.0 ppm measured over an 8 hour period.  This should be reflected in the NABERS spreadsheet as currently the NABERS protocol states that Carbon Monoxide threshold level is 10 ppm.
Suggested fixChange Carbon Monoxide threshold level to 9 ppm.


Issue raisedAccording to AS1680.2.2 a minimum of 320 Lux should be maintained on the working plane, this can either be on the horizontal plane or vertical plane.  Note that measurements of lighting levels should be in line with the Australian Standards, e.g. measurement of light levels on several desks and surrounding areas (e.g. corridors).
Suggested fixMeasurements of lighting levels should be in line with the Australian Standards.

NABERS waste


Issue raisedTwo different waste audit teams could arrive at 2 very different ratings for the same building.  In part this is due to lack of accurate source data (i.e. even the best waste records are not nearly as accurate as electricity invoices), which can’t be overcome by NABERS, but there are still problems with the assessment protocols which could be improved.
Suggested fixReview tool.

Assessment costs

CommentCosts are prohibitively high (up to $20K/site), which combined with issues re validity of the data has led to poor update of this tool.

NABERS data centre tool

Issue raisedNABERS Data Centres – Whilst I understand this tool has not yet been released – we are wondering how it will align with the more traditional PUE ratings for Data Centres?

Possible confusion in the market regarding the ratings, given that PUE is an already established rating system.

Suggested fixEnsure that the new tool is aligned to the PUE rating or that it is directly comparable.
CommentWhen are the other tools e.g. data centres going to be available?They have been “coming” for a long time now.

Future development of NABERS

CommentNABERS needs to perhaps consolidate a number of its sectoral ratings (energy, water, IEQ etc.) into an overall sustainability rating to accommodate international benchmarking.
CommentLook forward to NABERS education rating tool.
CommentWhen will NABERS start doing houses in NSW?

Comments submitted – no classification

Comment –

Heat exchangers

Would like a new standard to rate heat exchangers.  AHRI Type certification tool to be implemented to assess efficiency of heat exchangers in water to water applications.  Will help in attaining the highest Green Star rating for Buildings.  We need to put forward a suggestion on setting up a standard for certification of water to water heat exchangers to make sure client gets the most efficient system.  Would like to get involved more in the activities of NABERS from a heat exchanger supplier perspective.
Comment –

Survey format

I was expecting a survey with specific questions.  I was not expecting open questions when commencing the survey so have had not had time to contemplate greater philosophical or structural issues related to NABERS.  It would have been preferable if this on-line “survey” had a save and return function.
Comment –


I think green property is a load of baloney, scrap preoccupation with global warming.
Comment –

Rated display

Rated buildings should get some official form of display media/sticker, or some other way of promotion of its status.