The little house that could

The little house that could

Architects and designers have been a little slow when it comes to adopting greener building principles, and they need to wake up, according to builder and designer Lawrence McIntyre. His words come after the release of a report titled ‘Little Greenie – Get the Facts’, which focuses on a Golden Bay home which has been awarded the highest energy efficient rating for a house in New Zealand. Dubbed Little Greenie, the house was designed and built by McIntyre in 2008/2009 and has achieved the highest energy efficiency rating under EECA’s Home Energy Rating Scheme in New Zealand. Achieving nine out of ten stars, it reportedly has heating bills that amount to less than $70 per year.  

McIntyre's main focus when it comes to building is on insulation, something he calls "energy-based design" or "function over fashion". He hopes Little Greenie will help inspire the building industry and homeowners to build better performing homes.  

"It would take very little up skilling for every builder in New Zealand to use Little Greenie principles. And it would change the standard of kiwi homes overnight. But architects and owners are slow on the uptake. Wake up”, says McIntyre.  

He points to a New Zealand building industry where “builders are pumping houses out”, something he says is creating “a lot of bad energy and a lack of job satisfaction”.

Designing a house that is highly insulated involves a lot of craftsmanship and “builders are happier when they’re doing good work”.  

McIntyre has a gripe with an industry he describes as being focused on building cheaply and ignoring the long-term picture. 

He says having a well-rated house means, should you choose to sell, it will have a better value. Having the rating and built-in energy efficiencies also makes it easier for people to assess the long-term savings and investment to be made in a house.  

The construction of Little Greenie is centred around five core principles: energy efficiency, low maintenance and longevity, quality craftsmanship, and value for money. A lot of the inspiration for these principles derived from a trip McIntyre took to Germany back in 2003. The German’s are famed for clever design and McIntyre found an abundance of it there. He was impressed with the attention to detail and the fact that the Germans seemed to be walking the talk when it came to statements about efficiency and insulation. And so he went about blending German practices with Kiwi techniques and materials.  

 “They don’t suffer fools in Germany," says McIntyre. "If you say something in Germany, you’ve got to back it up.”   

According to the report, which was independently prepared for the Hikurangi Foundation, the Energy Efficiency Conservation Authority (EECA) and Little Greenie Design & Build by Housing Analyst Verney Ryan, the house provides the following key benefits compared to an equivalent size and design of house built to current building code standards:

  • A 9 star Home Energy Rating (HERS) rating as compared to a 4.5 HERS rating for a code compliant house.
  • Only marginal additional costs to build (at $2,136/m2 compared to $1,766/m2 for the code level equivalent), which provide a return on investment in less than 21 years and have the potential to add to the capital value of the house.
  • An estimated return on investment in excess of $77,000 over a 50 year period when lower maintenance costs are also taken into account
  • Little Greenie provides a practical and achievable method of building to a higher level of performance through well crafted passive solar design techniques and high levels of insulation, that deliver a unique opportunity to educate and inspire the residential construction sector in New Zealand.
  • Little Greenie delivers a comfortable indoor environment that meets World Health Organisation recommended indoor temperatures year round with minimal reticulated energy input. 

"What this house clearly shows is that by using a combination of good planning at the outset, good workmanship and quality materials people can have a home that is exceptionally comfortable and super-efficient all year round - and it doesn’t cost that much more than the average new build," says Christian Hoerning, senior technical advisor of buildings at EECA. "There are no space-age design and construction methods here; no expensive niche technologies, just conventional methods and materials, used in a much smarter way."  

The house uses a number of innovative design techniques that reduce the need for ongoing maintenance.The innovations, as outlined in the report, include:  

Use of steel cladding

The exterior cladding system has a number of advantages from a maintenance and product lifecycle perspective. There is no need to paint the surface as with timber claddings. It only requires a simple wash down once per year with light detergents. The outside steel ‘shell’ of the house is also designed as the protective covering for the thermal envelope. It is totally recyclable as well as being easy to remove and put back.  

Functioning Passive Solar Design

This reduces the need for technical solutions for providing heat and represents a maintenance free, low cost and environmentally benign way to heat the home. This should not be underestimated as the NZBC minimum house described above would in most instances have a heat pump installed – which may need to be replaced every 10 years (indicating an average cost of between $15,000 - $20,000 during a 75 year lifespan).  

Stainless Steel Perimeter flashings

This long lasting innovation provides highly finished detailing and neatly resolves the issue of how the perimeter concrete slab insulation meets the window and wall cladding. The nature of the stainless steel, and the construction of the concrete slab, means that the house ‘floats’ above the ground on a highly insulated pad. There are few, if any, materials in contact with the ground that will be susceptible to deterioration.  

Wool Insulation

This was relatively easy and pleasant to install, meaning that extra handling required for a ‘tight’ thermal fit was no problem. The breathability of wool and its capacity to absorb and release moisture may assist with improved Indoor Environmental Quality (IEQ) in the house as well as providing good lifetime performance.  

“Little Greenie provides a practical and achievable method of building to a higher level of performance … and delivers a unique opportunity to educate and inspire the residential construction sector in NZ,” concludes the report.  

And that education element is key for McIntyre. The Little Greenie house operates as a self-contained holiday home, particularly targeted at people who want to stay and learn about green building principles. He’s had one architect stay in the house, and according to McIntyre, that architect was impressed by the building. But he says for architects, function is not the main concern and too many are focused only on how a house looks. But he doesn’t have any advice to offer architects because he says “they already know this stuff”. 

And as for the future, McIntyre says he is currently awaiting resource consent to build a similar property in Auckland.  

You can check out the report in full HERE.

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