Golden Bay Hideaway

Tim Bishop, Sustainable Habitat Challenge National Coordinator:

Little Greenie shows what can be accomplished by when using sustainable building principles of Sustainable Habitat Challenge Teams

This house demonstrates the truism that more sustainable building is practical building: simple, durable, and good value.

The Sustainable Habitat Challenge (SHAC 09) is a national collaborative project for teams around New Zealand to design, develop, and build sustainable housing in their local community. Ten tertiary-industry teams have created designs, and seven are currently building or retrofitting their houses.

Sustainable Habitat Challenge Principles

• Less need for energy, water, and waste production.
• Adapted for the local environment.
• Cradle to cradle design.
• Simple, durable, and good value.
• Collaborative design and build process that has designers, the trades, and engineers working side by side from the start.
• Wide dissemination of information learned.
• Tertiary involvement for education, monitoring, and review.

Read more all about what SHAC 09 teams are doing at www.shac.org.nz

UPDATE: It’s confirmed, Little Greenie is the first HERS 9 star rated home in New Zealand.

Christian Hoerning from the from the Energy Efficiency and Conservation Authority tells it like he sees it:

The house received a Home Energy Rating (HERS) rating to independently verify the standard of the house’s energy efficiency. HERS is a scheme that we at EECA run. The house achieved a 9 star HERS rating which is only one step away from being a zero energy house (the rating scale is between 1-10). This is likely the highest rating a house in NZ has received to date – we are verifying this today but it looks highly likely.

A few other points to note:

• While this is not a low-cost design, it’s not luxurious either and is therefore achievable for many New Zealanders today.
• The house has been designed to achieve good aesthetics, great comfort, very high energy and environmental performance and minimal maintenance requirements at reasonable building and minimal running costs.
• The annual heating demand is about 85% lower than for an average new build built to code minimum requirements, and about 97% lower than for an uninsulated house in the area.
• The owner is very happy to talk about the HERS rating publicly and welcomes any publicity.

The owner has also installed many data loggers to monitor the actual energy performance and proof that it works – this will be evaluated by the School of Architecture of Victoria University of Wellington.

As this example demonstrates, international best-practice, highly energy efficient and future-proof Kiwi home design is already achievable using products and techniques which are readily available in New Zealand and do not need to cost an arm and a leg.

As this house is a holiday house this is an opportunity for other New Zealanders who consider building to visit this house and experience the comfort of ultra-low energy houses.

The Home Energy Rating Scheme is an invaluable tool which assists New Zealanders with making informed decisions for achieving energy efficient home designs.

The key points which helped achieving such a highly energy efficient house are:

• Compact, simple building layout
• Good solar orientation of windows
• Super insulated roof, walls and floor – more than twice as much insulation as required by the building code.
• The thermally best performing double-glazed windows available in NZ have been used.
• Thermal mass in the concrete floor and adobe walls collects the sun’s warmth on sunny days and release it overnight and on cloudy days.
• Solar water heating for hot water and underfloor heating.
• Attention to detail in the design.

HERS Report showing our score of 9/10

We’ve just received our preliminary Home Energy Rating Report (HERS) from the Energy Efficiency and Conservation Authority and we’re very proud. Little Greenie gets 9/10 and as far as we know at this stage this is the best HERS rating given out so far in NZ. We’re looking into confirming this but it seems likely.

What does the HERS report mean? From the report:

The building rating is a measure of how well a home’s design, materials and solar orientation enable it to maintain a healthy and comfortable indoor temperature throughout the year.

The report also rates the house’s water heating performance:

The water heating rating is a measure of how energy efficient a home’s water heating system is.

Little Greenie received a rating of 10/10 and an indicative running cost of $41/year. That’s right $41 per year for all water heating costs!

We also get a list of Key Recommendations For Improvement:

1. Reducing area of windows in lounge by 50% reduces heating load by approx. 60%
2. Deleting skylights reduces cooling load
3. Increasing thermal mass by increasing concrete topping from 50mm to 100mm reduces heating load by approx. 40%

Maybe some room for improvement then?

You’re welcome to view the full report.