Australian Passive Solar Home

Since building our house, one thing I have become intrigued about is the cost of new houses in Australia.

But first, I need to make a few points about our house.

Our house, as covered on this blog, is deliberately plain and simple – just a basic rectangle with a gable roof. In its shape, it could in fact have been a shed – not surprising, since our original plan was for a shed-based home. Furthermore, that plain and simple house was owner-built – I directly employed the contractors, and did whatever work I could myself.

Both approaches saved about 40 per cent over having a more complex house, of the same floor area, built commercially.

In what follows I am not suggesting you must take our path – literally, do whatever you want!

So what has intrigued me? Well, in Australia, it seems that there are two cost scales used for houses. What I’d call normal houses, that are available from commercial builders, and so-called ‘architect designed’ homes, which seem to be very much more expensive.

But before I go any further, lets define what I mean by cost. By far the best way is to evaluate the cost on a per square metre basis. That is, the total cost of the house, completed but not furnished, divided by the area of the internal living space. The cost includes earthworks for the house pad, but not garden landscaping, an external shed, etc.

At the time of writing, January 2026, according to this source, the average cost of an Australian new home is $1,800 – $4,500 per square metre. Another source lists it as $1,600 – $3,000 per square metre. If we take an average Australian house, with a floor area of about 230m2, that gives a cost of about $370,000 to $1M… a big range!

But if we take an average within that range, we get a bit over $3,000 per square metre or about $700,000 for an average sized (230m2) house.

Note that comparing house build prices from – say – five years ago is not viable; you must instead recalculate for the average at that time.

Why all these numbers? Well, what I have found is that while mainstream building companies are fairly transparent about the costs of their various designs, and so the cost per square metre is easily calculated, architects showcasing their custom homes are very reluctant indeed to state how much they cost per square metre.

In fact, when architects are asked about costs per square metre (e.g. on their social media posts promoting their houses), often they’ll state it’s an inappropriate way of quantifying home build cost!

And when it comes to architect-designed, energy-efficient homes, things get worse – far worse. The penchant for architects to use very expensive ways of achieving high energy efficiency – think expensive windows, expensive sealing, expensive ventilation systems, expensive certification and so on – mean that their houses, on a square metre basis, are (not surprisingly) usually very expensive indeed.

That’s why they don’t want to use a square metre cost – it’s too revealing.

In my naivete, I must admit that before we built our house, I thought that architects could, if asked, be specialists in reducing the cost of an energy efficient home. After all, they should have the skills to make parts of the constructed house perform multiple functions, saving money. (An example? A decorative screen that gives privacy and blocks summer but not winter sun – i.e. the screen performs three functions.) But that simply doesn’t seem to be the case.

If you want an expensive, elaborate, sophisticated, energy-efficient home designed by an architect – great! No problem at all. Go for it.

But, based on what I can see occurring time and time again in published houses, if you are on a tight budget and want to achieve the best home for the money, be very careful of using an architect. Not without setting a maximum build cost per square metre, anyway.