Same house + different climate = different star rating
House star ratings are climate specific - which makes sense. Unfortunately, very few people even in the housing industry know this.
Don’t let anyone tell you that it’s difficult to design energy efficient homes with NatHERS star ratings of 8 stars and above…UNLESS you live in Tasmania or the more extreme climates in some parts of the mainland.
Here’s an example to prove our point. Here is a concept design we presented recently for a home in Canberra on a tricky site in O’Connor. When we simulate its thermal performance in cities in different climate zones without ANY design or specification changes, here are the results:
Canberra: 8 stars
Hobart: 7.8 Stars
Melbourne: 8.3 stars
Adelaide: 8.7 stars
Perth: 9.3 stars
Sydney: 9.9 stars
Brisbane: 10 stars
In real life we would of course tailor the design to the local climate so this should actually be an underestimate of what can be achieved (i.e. in Brisbane we should be able to get 10 ++ stars!)
Also it’s important to note that the scale is not linear - in Canberra an 8 star home requires 53% less combined energy for heating and cooling than a 6 star home of the same size. And, that the rating is per square metre so if your 8 star home is twice as big as your neighbour’s 8 star home it will cost MUCH more to run.
Six stars is a pathetically low standard. Shoot for the stars everyone!
To learn more read our other posts on EERs and star ratings.
