Claudia Kaltenstadler

Lack of knowledge on the part of homeowners is one of the factors slowing demand for energy-efficient, sustainable homes, according to Harakeke Consultants founder Claudia Kaltenstadler.

The wider property sector, including real estate agents and valuers, is still also on a learning curve regarding the benefits of healthy homes with lower running costs, she said.

Originally from Germany, since moving to NZ in 2006 Ms Kaltenstadler has been advising builders, designers, architects and aspiring homeowners on improving home performance, using European standards for air tightness, insulation and reduced materials footprints as a reference point.

Ms Kaltenstadler also founded the Christchurch Professional Property People networking group, which is affiliated with similar groups in Auckland and Wellington. The group brings together investors, designers, council representatives, builders, lawyers, accountants, real estate agents and others for the purposes of knowledge-sharing and collaboration on projects and initiatives.

Lack of awareness on green construction

She said that energy efficiency and sustainability were not always topics of discussion, and that this reflected the broader trend of lack of awareness and understanding.

For example, few are aware that 80 per cent of a home’s heating energy is lost through lack of slab-edge insulation. In Europe it is standard practice, but it is still uncommon in NZ, she said.

Air tightness and leaky home syndrome due to lack of proper ventilation were two other issues compromising energy performance and the health of occupants.

“There have been deaths here from mouldy homes,” Ms Kaltenstadler said. And it’s the vulnerable groups who spend the most time indoors – elderly people and toddlers – most at risk.

“If you seal a home and make it airtight and you haven’t got mechanical ventilation, you have problems of condensation and mould,” she said.

A contributing factor is also that past practices of opening windows when cooking or after showering to release condensation have been replaced with the use of standard extractor fans in bathrooms and kitchen range hoods. These are not enough to take the moisture out, Ms Kaltenstadler said.

Aluminium window frames can also contribute to the problem. If they are not installed with a thermal break and inset deeply enough into walls where the insulation is, they become a source of condensation.

The trapped moisture inside homes can also further reduce energy performance when it gets inside the walls and into insulation, as it reduces its performance.

Ms Kaltenstadler said an energy-efficient solution to reducing condensation was a mechanical ventilation system that incorporated heat recovery.

The combination of complete insulation, including slab edge, thermal breaks, a well-sealed building and proper ventilation systems were the way to ensure a healthy, warm and energy-efficient home, she said. These are similar to the principles of PassivHaus, however achieving certified PassiveHaus standards in NZ is at this point “too costly”.

What is being achieved is showing that it is possible to achieve a similar outcome without major added costs.

For properties her firm consults on, blower door tests are used. This is not compulsory in NZ, as it is in Europe, but she would like to see all homeowners receive a certificate of the degree of airchange in a building.

Tackling “bigger is better”

Another area of the firm’s focus is countering the “bigger is better” mentality in residential construction. Ms Kaltenstadler said in Europe, dwellings were generally smaller in addition to being more comfortable, and that this was a trend NZ would do well to adopt to improve sustainability.

“We need to walk away from ‘big big’ thinking, where the home is using so much energy and it is not environmentally friendly,” she said.

The big hurdle, as she sees it, is overcoming lack of knowledge in the market about the ways and means of sustainable homes.

“If people are not educated, how will they know? There needs to be education [of the market] so people know what to ask the real estate agent and builder,” Ms Kaltenstadler said.

“There needs to be compulsory education, like HomeStar, with a practitioner day for real estate agents. So if they want to sell an energy-efficient home they have the knowledge.”

She said this would also help agents be more successful in the future as the market became more focused on healthy and energy-efficient homes.

Policy shifts

One policy shift that may make it more important for agents to understand the relationship between energy efficiency, thermal comfort and building health is recent changes to the NZ Residential Tenancy Act announced in July this year. Under the revamped act, many landlords will have to retrofit insulation to their properties.

Building and housing minister Dr Nick Smith said the changes to the act would “make homes warmer, drier and safer for hundreds of thousands of New Zealand families without imposing excessive bureaucracy or cost”.

“The new law will require retrofitting of ceiling and underfloor insulation in rental homes over the next four years,” Dr Smith said.

“There will also be a new requirement from 1 July 2016 for all landlords to state in tenancy agreements the level of ceiling, underfloor and wall insulation to help better inform tenants.

“These new insulation requirements in our tenancy laws are the logical next step following our program to retrofit insulation in 53,000 state houses and the 280,000 grants from the Warm Up New Zealand scheme.”

It’s a step back from the initially proposed Warrant of Fitness Scheme, which would have enforced disclosure of thermal comfort and energy performance.

Ms Kaltenstadler said the reason the government abandoned the proposal was that too many investors would have decided to sell their properties rather than accept the need for a WOF.

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  1. Sounds like a familiar problem and you’re right it needs a multifaceted approach. Not sure if you’re familiar with the work of Some great work around the real estate industry. We at Master Builders Victoria have been increasing industry knowledge through the Green Living program. Keep up the good fight. Phil