KEY POINTS:
When Matt Heale and Megan Courtney were planning an extension to their two-bedroom home in Pt Chevalier, energy efficiency - and cost - were among their key considerations.
The move was as much about pragmatism as it was about principles.
"Basically it was a very small house and we were planning on having another child so we needed more space, but also it was fairly cold and cramped, so this gave us a good opportunity to improve those aspects of the house," said Mr Heale, a town planner with eco-conscious Waitakere City Council.
Built facing north to maximise sun exposure, the extension housing the 1930s stucco brick bungalow's kitchen and living area was built above building code specifications with an emphasis on energy efficiency.
Little touches such as minimising windows on the southern side and a concrete slab running along the sunniest part of the floor mean the extension needs little additional heating, even in winter.
"We tried to think about all of the things that add up to make the place work better," said Ms Courtney, a social planner.
The change to the family's comfort levels was immediate.
And this month, the couple found out just how much more energy-efficient their home is when it was assessed using a new ratingssystem.
The Home Energy Ratings system, launched last Monday, is an independent assessment of the energy performance of a home, expressed as a star rating.
Assessor Ben Bell gave the couple's home 3 1/2 stars - a very good rating for a house of its age.
The extension played a big factor in the good rating, as did the addition of a solar-hot-water panel and ceiling insulation in the original part of the house. All up, it cost the couple $120,000 to build the extension, centralise the plumbing and move and modernise the bathroom and toilet - money they and Mr Bell consider to have been well spent.
Mr Bell said the ratings system allowed householders to calculate what modifications would bring the most benefit.
And his suggestion of installing underfloor insulation in the original part of the house is something Mr Heale and Ms Courtney plan to take up. Energy Efficiency and Conservation Authority chief executive Mike Underhill sees value in doing the assessment, which will cost around $200 for a typical house.
"It's showing you what you can do to your house in an unbiased way so you can improve your health, the state of your house, and reduce your energy bills."
The authority will monitor the effectiveness of the programme before it makes submissions to the Government at the end of next year on whether the system should be left voluntary or made mandatory with each house sale.
Mr Underhill said systems such as these were being introduced in places like Australia and Canada, and the European Union would be making it mandatory in three years.
He said there were some issues to be worked through around making it mandatory, such as who would pay, and if it would affect the values of older houses.
"A house is by far the biggest investment that most of us make. And there's a fair bit of the house, in the emotion of buying it, that you can't actually see.
"We just think that if you're going to spend many hundreds of thousands of dollars, the amount you pay for energy is an important part of it."
* The Home Energy Ratings system
