4 December 2013 — Last week’s article by André Stephan and Robert Crawford, Why energy saving homes often use more energy, raised important questions about embodied impacts, size, location, lifestyle and transport but made no suggestion as to how they might be addressed by building regulations (the subject of the article).
While these issues (and many more) are critical components of low carbon futures, perhaps we should first consider whether building regulation is the most effective way to address them. I propose that it is, but it is one of many pathways to a zero carbon future and not necessarily the best in its current form.
- See our post, originally published in The Conversation, Why energy-saving homes often use more energy
The thinking underpinning current regulations originated in a time when mitigation to avert critical climate change was still considered possible. Since then, we (humanity) have missed several critical mitigation deadlines and warming exceeding the “critical” 20C limit now appears inevitable.
While mitigation to limit further warming remains an essential objective, adapting our buildings to best cope with the inevitable consequences of those missed deadlines has become equally important.
Accordingly, I argue that re-thinking and contemporising our regulatory focus and re-defining its objectives is an essential first step. Only then can we effectively expand the scope to address all the elements of a zero carbon future including the embodied impacts, transport and lifestyle raised by Stephan and Crawford.
This process would also identify the most effective interventions for each impact in each sector and hopefully, recognise that any benchmarking system should be capable of measuring a full range of performance, from minimum compliance to best practice innovation – not just minimum.
“Mandatory regulation enforces minimum standards whereas voluntary best practice rewards those who innovate”
Mandatory regulation enforces minimum standards whereas voluntary best practice rewards those who innovate, refine and demonstrate the commercial viability of innovative new practices and technologies.
Innovation has inherent risk and cost implications that the best practice sector is less sensitive to.
When innovations have been tried and tested by these innovators, market forces ensure innovation transfer or diffusion through to increasingly risk averse, cost sensitive market sectors. Market influence includes: quality assured product availability; economies of scale and market demand. Each is driven by minimum practice regulation.
The impact of carbon pricing in Australia has already seen rapid shifts in the supply–demand cycle for carbon reducing technologies and buildings. While current short-term uncertainty about continuation of that policy is problematic for exposed industries like the renewables sector, consumer demand continues to grow across the broader market.
In other words, the market currently provides a viable pathway through which to develop, apply, test and refine the knowledge and solutions required to reduce embodied impact. Carbon pricing and mandatory minimum standards provide the catalyst to ensure market penetration. I suggest that embodied impacts should remain integral to the voluntary code of best practice until industry understanding and consensus regarding metrics and achievable benchmarks is further refined.
Modernising existing housing regulations
In terms of carbon/energy efficiency, much has changed in recent years and our regulations have not kept up. I attribute this (at least in part) to the decision to deliver energy efficiency regulations through the Building Code of Australia/National Construction Code. Sustainability is a rapidly developing field that is arguably ill suited to Australian Building Codes Board consultation and Regulation Impact Statement protocols. These were developed to regulate minimum compliance standards in the built environment where the urgency of climate change is not a factor. They are highly effective in that role.
Sustainability standards would arguably be best delivered via a flexible, online protocol such as BASIX where new technologies can easily be added, guidance to applicants about alternative solutions can be provided at point of decision and illustrated with case study links and examples. Benchmarks can also be easily adjusted to keep pace with technological advances.
Affordable renewables, Minimum Energy Performance Standards driven increases in appliance efficiency (particularly heating and cooling) and the potential for carbon zero grid electricity supply have rapidly and radically moved the goalposts for achieving carbon zero/positive status (the primary objective). This requires an equally rapid and radical shift in the regulatory interventions that dictate industry approaches to cost-effective carbon emission reductions in the buildings we are making now. For example:
- The NatHERS star system continues to use the metric megajoules/square metre while house size has doubled and the number of occupants has more than halved in many markets. Changing this metric to per household (or even per occupant) would make infinitely more sense.
- The carbon intensity of our energy supply is changing rapidly. While energy efficiency was always a questionable metric, it is now completely misleading and will become increasingly redundant. To address the real objective, the NatHERS metric should be changed to carbon emissions as is the case with NSW’s BASIX program.
- On site renewable energy generation has become economically viable and yet only a handful of state amendments to the energy provisions in BCA/NCC formally recognise its contribution in their ratings. NSW’s BASIX is the only system to fully incorporate it. (Photovoltaic costs: 1998: US $12/watt; 2013: US $0.75/watt; 2020: US $0.25/watt?)
- Carbon Zero grid electricity supply has moved from utopian dream to achievable reality by 2020. Even if government and business inertia extends that time frame to 2030, it is still less than halfway through the expected lifespan of today’s new buildings. Grid carbon intensity is already reducing and this should be reflected in regulatory compliance options.
- Embodied carbon will never be higher than it is now. Its contribution to climate change is locked in at the factory gate and can never be recovered. High thermal mass construction typically has high embodied carbon and cost. NatHERS simulation rewards high mass solutions in many climates due to assumptions based on historic weather data.
- 2-30C of climate change appears inevitable and yet our regulations encourage housing solutions based on historic weather data. Limited research already suggests this will prove increasingly problematic – particularly in high mass solutions. See AIRAH: Upsizing cooling capacity may not be enough, research finds
- Water or phase change mediums are low/no embodied energy mass substitutes that can be drained, moved or relocated to adapt to changing climates. They can also be used to effectively store both passive and mechanical warmth/coolth – shifting demand to off-peak periods. As well as reducing the need for more expensive poles and wires, this can yield a better return on investment in photovoltaics. Such thermal storage can facilitate the use of renewable electricity generated on site to heat or cool when grid feed tariffs are lowest to provide thermal comfort later – thereby reducing peak demand. NatHERS is currently unable to fully model the role and contribution of phase change materials – particularly in capping temperature extremes and reducing “degree hours of discomfort”.
- MEPS rating bar creep has seen the coefficient of performance (COP) of heat pump heating and cooling appliances shift from 2 to 6 in recent years. This phenomena is likely to continue – particularly in view of recent advances in solar heat pump technology that are yet to enter the Australian market. These advances challenge NatHERS assumptions about energy use/carbon emissions from residential heating and cooling. When climate change considerations are factored in, well insulated low mass construction with well designed glazing/shading will become an increasingly viable construction solution in terms of lifecycle carbon emissions – particularly in heating dominated climates. This will be further canvassed in the fifth edition of the Your Home Technical Manual, due for release in January 2014.
- Our current regulatory focus is limited to new homes and major additions. This addresses only two per cent of our housing stock in any given year. Any revision of regulation must fully address existing housing. Mandatory Disclosure of carbon and water performance at point of lease or sale must be central to this. An innovative new assessment tool to benchmark existing homes would be highly beneficial.
In closing, while I agree with Stephan and Crawford that high NatHERS star ratings based on high mass solutions in Victoria’s climate will likely yield a poor lifecycle carbon outcomes, I challenge generalisations regarding the net lifecycle carbon value of all thermal performance solutions (high and low mass) and, specifically, those derived from insulation.
In combination with current over-glazing, poor orientation and shading practices, high mass solutions will become increasingly inappropriate as the climate warms. However, short term heating and cooling emissions from older, less efficient appliances will always be reduced by adequate insulation. Additionally, in the longer term, increasing seasonal temperature peaks suggest that insulation will become increasingly critical – regardless of embodied energy.
Finally, I found the example comparing total energy use of two Melbourne houses (6 and 9 Star) with an apartment building in Brussels unhelpful and confusing. While indicating that apartment lifestyles generally require less transport energy and their size is generally smaller, it did not address the fact that apartment construction generally has significantly higher embodied energy than individual homes and duplexes due to their increased use of concrete and steel. I am sure there was sound research underpinning this but it raises more questions than it answers when published in this format without detailed explanation of the context.
Dr Chris Reardon is the principal author of the Banksia Award-winning Your Home sustainable design guide and currently specialises in sustainability training and design/construction consultancy to industry.