Green houses fail to deliver?

A serious problem has finally caught the media’s attention: that so-called sustainable buildings ain’t always what they’re supposed to be. The ABC’s 7.30 program aired a story of a house that rated 5 Stars at design and approval stage actually achieving 3.5 Stars in ‘as built’ testing. Envirotecture director Dick Clarke was recently pointed to systemic problems with certification during construction, in SMH’s Domain, which is part of the same problem.

The problem is in two parts: first, at design stage, we just don’t know if 5 or 6 Star rated houses (or 4.8 Star under BASIX in NSW) actually CAN achieve that level of performance, because the NatHERS simulation software and/or BCA mandatory requirements have never been validated against real world performance. Secondly, once construction commences, there is wide range of compliance and certification failures allowing design and specification details to be omitted or changed on site. The combination of these two woeful situations means we are still building crappy houses across the nation. In every state, gov’t policies and regulations that are supposed to achieve improved thermal performance and reduced energy consumption are failing to deliver as promised. In NSW, BASIX commitments are often flouted – and this is in breach of the law. Nothing much is being done to tighten a very loose system.

For years industry leaders have been calling for broad based research that seeks to correlate ‘as built’ performance with ‘as designed’, and to validate or adjust the NatHERS simulation software (AccuRate, FirstRate, or BERS Pro), or the Building Code of Australia’s mandated compliance. The Federal Gov’t has finally committed some funds to begin this process, but the calls went unheeded all through the Howard and Rudd years. Let’s hope it’s better administered than the Green Loans and free insulation schemes.

At Envirotecture we take building performance very seriously. We recently raised the bar for new residential buildings to 8 Stars for all new Envirotecture houses. But how do we KNOW that will be achieved? We can’t know for sure, when there is no ‘as built’ testing against an agreed standard. Without such a standard, occupant behaviour makes any data meaningless – some people live frugally, others extravagantly, no matter how efficient the house. And without the research, we cannot arrive at a standard test method, in theory, methodology, or field testing method. And without the testing, we can never validate the software.

So let’s get on with it!

In the meantime, we (building designers) can all specify the best stuff we can, write a tight spec, detail what’s needed, and work with good builders to achieve the best result possible.