Question: How important is Energy Efficiency in my next housing design?

Question: How important is Energy Efficiency in my next housing design?


The energy efficiency rating (or “star” rating as some builder refer to it) is a means by which we can estimate how difficult, and therefore how expensive, it might be to heat your home during winter, and to cool your home during summer.

Consider not only the heating and cooling costs, but the resale of your new home down the track. Imagine two similar homes, in similar areas, one designed to be energy efficient, and the other with those principles ignored. How much of a premium can the energy efficient design command over the other home?

Currently the minimum star rating necessary to have a home approved is 6 stars. This is calculated using NAThers software such as BERS or First Rate. You can also use the method of verification using a reference building. This is not a star rating as such, and is usually employed to help get a lower rating design through the shire approval process.

The of the word to focus on here is “minimum”.

There are a lot of minimum standards in the building industry. From the amount of roof timber you use in the roof structure, to how you waterproof a shower. You don’t have to accept any of them, and fortunately a lot of energy efficiency comes from the design of the home, not expensive add-ons.

In the case of Energy Efficiency, a lot of builders, either through a lack of understanding, or a wish to limit your options as a client, have the shortest possible discussion about the topic. It is so much easier to say to you… “we will submit your home to the experts and if for any reason it doesn’t meet the 6 star requirement, you might have to pay for cavity wall insulation or something…”.

Unfortunately I see it all the time. Unqualified sales consultants trying desperately to get the signature at the bottom of that piece of paper, and taking the path of least resistance (and least information) to get there.

Discussions about Energy Efficiency should be held with suitably experienced, and suitably qualified designers.

At Coastline Homes, you actually sit with a Greensmart Accredited designer, and far from being a hidden subject, Energy Efficiency is ranked alongside liveability of design, material selections, and aesthetic performance of your home.

If you want to test out a couple of those salesmen in those expensive display homes, try throwing a couple of these terms at them, and see how competent they are in explaining how they work, and more importantly how they will apply to your home.

Orientation:       Most of us understand what it means to orient a home to North (although I still see it messed up a lot of the time). But what is considered the acceptable degree off North for primary winter heating windows? Which windows should you face North?

Shading:               North facing windows get a lot of sunlight during summer as well as winter. This is handled by designing shading that restricts that heat during summer but allows it in during winter. So what is the difference in the suns azimuth between winter and summer, and how much shading is optimal?

Heat Sink:            What exactly is a heat sink and how does it operate? How is it best used in a home without limiting design or space?

Insulation:           Is it better to insulate at the roof tiles, or at the ceiling. What is the pay off in an insulations R Rating?

Energy Efficient Glazing:                               What are the glazing alternatives? Where should it be applied?

Construction Materials:                 How do timber floors effect overall performance of a home?

Is Timber Framing less or more energy efficient than brick?

How does Cavity wall insulation work?

These are basic questions, and ones which any designer/ sales consultant you are entrusting to design or orient your home should be able to answer confidently.

These questions are also only a starting point, and most designers should know far more than this level of detail.

An experiences accredited designer will be able to incorporate Energy Efficiency into your home, without breaking the bank.



Kevin Blackwood

Director Coastline Building Group WA Pty Ltd