Australian Passive Solar Home

So many energy-efficient house designs in Australia are inordinately expensive. To many people, that just goes with the territory. But what if you cannot afford to pay half as much again for a newly-designed house?

The good news is that you can get very good energy efficiency in most parts of Australia by simple passive solar design. This is in fact what is recommended by the Australian and all State governments, backed by research from the CSIRO.

And such a house need not cost any more than a normal Australian house. Zero, zilch, zip… no more at all. Standard timber stud wall design with R2.5 insulation, standard timber rafters with R5 insulation, standard Colorbond roof, standard concrete slab. In many areas you will benefit from double glazing – pretty well standard these days anyway.

So what tricks do you employ?

The first thing is that you must have passive solar design in your mind from the very beginning of the house design process. That will help determine the best orientation, the optimal amount of window area on each face, the width of the eaves, and the preferred locations within the house of the living and sleeping areas – even the best floor coverings.

The next thing is that, early in the process, get an energy rater to run a NatHERS computer simulation. In addition to telling you the total energy used for heating and cooling, this software can show you the temperature in every room on every day of a typical year! Tweaking aspects such as windows (eg type and area), eave width (used to let winter sun in but keep summer sun out), and many other aspects, takes only minutes for each simulation. No more guesswork – see what will actually happen! Because this software is used to generate the legally required star rating for the house, numerous energy raters are around who can do this quite cheaply.

The legally required star rating is now 7 – but getting this is really very easy if you’ve kept passive solar design in your mind from the beginning. Depending on the location, getting 8 or even higher star ratings is quite achievable… all at no extra cost, remember.

Please don’t do what I see so many people do – and that’s think about passive energy efficiency only at the end of the house design process. By then so many aspects are baked-into the design that getting the energy star rating up is often very expensive.

The best resource on all of this is the Australian Government’s YourHome website. It has excellent design advice in easy to understand language.

To have an energy efficient home in Australia, you don’t need weird and expensive stuff – just basic good design.