Australian Passive Solar Home

I am writing about southern Australia, but I imagine the same would apply in most locations. When building energy-efficient housing, as soon as you move away from the most common construction approaches, materials and techniques, costs go up a lot.

That’s a deceptively simple statement because it immediately implies that a great many things that energy experts often recommend (often? nearly always!) will make the house much more expensive.

Sealing wraps installed very carefully; thicker insulation (and so usually different wall construction); mechanical ventilation; triple glazed windows; SIPs (structural insulated panels); special construction techniques to avoid thermal bridges, specially trained tradespeople – and so on and so on.

After all, it’s very easy to improve the performance of a dwelling if you spend a lot more. (In fact, it’s very easy to improve the performance of anything if you spend a lot more.)

On the other hand, improving the energy efficiency of housing without spending any more money than for a normal home requires very careful design and execution.

It’s unfortunate that nearly every architect, energy advisor and consultant I come across seems to tell potential clients that they need to spend very large amounts to gain an energy efficient home… when in fact in most locations, they don’t.

Anyone recommending materials not available at your local friendly building and window suppliers is a red flag for cost. Anyone recommending that tradespeople specially trained in building energy efficient homes are needed to construct your home is again a red flag for cost.

Standard Australian building materials and trades are perfectly capable of being used to build a highly energy efficient home in Australia. People who say otherwise are, 99 per cent of the time, trying to sell you something.

The only addition – and it’s an important one – is that you should employ a professional, independent inspector to check on the quality of building work at each stage. That will add less than 1.5 per cent to the total cost of most houses.