Tuesday, 22 November 2011

How good is BASIX?

This is actually old news, but with a bit of a new relevance.

The NSW Department of Planning (now also Infrastructure) runs an on-line planning approval instrument for all dwellings constructed in that state of Australia, dedicated to aspects of sustainable new construction.  To the best of my knowledge, this Building Sustainability Index (BASIX) is unique in the world, not because of the comprehensiveness or stringency of its requirements, but simply because it is on-line, with no alternative ways of getting the required certificate.

One of the advantages of an on-line system is that it is so ruthlessly good at capturing data - you don't have to do surveys with sampling, you are constantly taking a rolling, up-to-date census of all dwelling construction in the state.  

Periodically, the Department releases reports on the 'outcomes' of the BASIX regime.  Available now are reports on single dwellings, multi-residential projects, and alterations.  They are getting a bit old, with the critical multi-residential review being only up to 2009 - so why do I choose now to draw attention to them?  Well, as I blogged a few days ago, there is a review going on, of the highly influential Residential Flat Design Code.  One of the great unknowns in that review is what relationship is there between that Code, and the outcomes hoped for through BASIX.

The first important news is that the reports are easily accessible.  This was not always so; for a while you couldn't actually find them on the BASIX web site, or anywhere else.  Almost as if someone was embarrassed by the content, and wanted to bury them.

Secondly, the BASIX Outcomes Reports are an extraordinarily rich source of data on all the physical characteristics of dwellings being constructed, as well as all the choices designers are making for construction, glazing, landscaping, dwelling sizes, common area lighting - you name it, it's there.  There are exhaustive tables of how those dwellings are rating against the metrics. The data could keep some researchers going for entire academic careers.

So what is the bad news?
It's rather subtle really.  The possible problem with the original two reports on single dwellings was that for all the bluster about how effective BASIX has been in improving the thermal efficiency of building envelopes, each had in it a single telling graph.  Which showed that per household energy use had continued to rise. That was the elephant at the table noone really wanted to talk about.  They solved that problem in the report on multi-dwelling outcomes.  While the report tells you in gory detail what the applicants are telling the Department they are going to do, nowhere in the report is there even a hint of what they actually do after they get their planning approvals, or how those buildings are actually performing.

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