Some considered it a bold move and it certainly was a shift in the right direction when the previous Victorian (Labor) government moved the state to six-star homes for energy efficiency, a move that has been replicated in other states such as South Australia and Queensland; in the latter additional costs of meeting the standard were estimated to be just 1.25% versus the previous baseline.
It’s great to get the country aligned around a serious ratchet-up of domestic housing building standards. However, where do we go from here?
I guess the general thinking would be to choose seven stars and aim for that to be adopted as the new standard along the way to 10 stars. This is a great idea and we should all fully support a move to supremely livable 10-star houses that barely need any heating or cooling input, both in the northern tropics of Queensland and in the coldest parts of Tasmania.
But there is another option and that is to choose to police building ratings and the actual finished buildings themselves, before certificates of occupancy are issued. That means a system of proscribed rating certificates just like we have today for plumbing and electrical work. A building-rating inspector would come around with a thermal imaging camera and blower door to test for air leaks, and rate the building envelope for thermal performance and air-tightness. The building plans would be inspected and checked for compliance and the building itself would be checked to see that it closely approximates the plans.
In the case that the building does not meet the six-star standard, the building owner will be responsible for improving the building's performance, like having to tune up a sooty car. Usually this will involve topping up insulation and caulking/sealing air gaps that have been scientifically identified. In extreme cases (if not already chosen) it would also involve replacing glazing with double glazing in a retrofit situation.
With an attention to home air-tightness, options such as ducted gas and evaporative cooling will be outed as poor performers and the superior option, of split system reverse cycle air-conditioners, would likely be taken up. Kitchen installers and plumbers would learn to seal up wall penetrations and electricians would install gaskets for sealing electrical outlets.
Furthermore, builders would be responsible for ensuring that sealing occurred above and below window architraves, skirting boards as well as around door frames. Finally downlights would either be avoided or appropriate downlight covers installed which extend the building envelope over otherwise very conductive materials that LED/halogen downlights are made out of, preferably the kind that are sound proofed and insulative with a fire rating and can have thermal insulation run up against them, avoiding the thermal bridging Swiss cheese effect that currently exists with downlight penetrations.
If this approach was taken to six-star building compliance, the industry would very quickly learn the tricks to reach compliance. This may include bringing in an external consultant to do a check before rough-in, as is the practice in Europe with their high performance houses (relative to ours). Builders would initially follow this route to avoid being failed by inspectors. But one would expect that after a short time getting up to speed, they would become familiar with what is required to make a compliant home to meet the six-star standard, as part of their normal building process/practice.
With this change in attitude and thinking, moving to the next stage, nationwide seven- or eight-star houses will be less troublesome. Most importantly, it would be truly reflective and consistent in their rated and actual performance.
This is unlike today’s current batch of six-star rated homes, which only make around four stars due predominately to build-quality issues and variations on original plans.
The building industry is capable of achieving higher star-rated buildings that perform as they should. The peak building industry bodies, HIA and MBA, know this and should get behind it.