New recommendations to build NSW schools to passive house standards could see students breathing cleaner air, with indoor carbon dioxide levels up to five times the recommended limit in some conventional schools.
The recommendations come from a feasibility study done by Grün Consulting and Envirotecture for School Infrastructure NSW that pits a current school design against one designed to the passive house standard.
In the passive house prototype school CO2 remained below the concentration that begins to affect cognitive function (greater than 1500 parts per million). Conventional schools, on the other hand, show CO2 levels up to five times the recommended limit.
Better air quality is linked to increased attention and the possibility of improved academic performance, according to the report.
“As we spend about 90 per cent of our time indoors, the quality of the interior environment is more important than ever, and for schools – spaces that serve vulnerable and developing humans – the quality of environment can have considerable impact on the occupants.”
As well as health benefits, the research found economic and environmental benefits. The prototype saw huge reductions in energy for the passive house version: 90 per cent less for heating, 42 per cent less for cooling and 62 per cent less energy consumption overall.
Passive house schools would also have lower maintenance costs, thanks to simplified or smaller infrastructure (including airconditioning) and greater longevity thanks to the better quality and durability.
Another saving flagged by the researchers was the streamlining of Green Star ratings, with the government recently nominating a 4 star rating benchmark as the minimum standard for new projects (this is not yet a formal commitment).
Passive house certified projects are allocated 30 points (of a total 100) under a deemed-to-satisfy pathway in Green Star. A 4 star rating requires 45 points.
“The approach could significantly streamline delivery,” the report says.
It also looked at the local market readiness to deliver schools at the passive house standard. It found that in any new market for passive house-type projects a 10 per cent premium can be expected, depending on the comparative baseline and the required improvements.
Despite the premium the report found that the life cycle costs assessment is positive.
The international experience also suggests that passive house will eventually cost no more than a conventional build.
“Many international markets have worn the path of a maturing market and eventually seen the passive house market grow to support the delivery of cost parity or cheaper project.
“The provision of high-quality buildings has the potential to impact on factors far beyond the reach of traditional economic models, or simply hard to include in a model with discrete boundaries.”
The researchers warned, however, that site impacts can entirely undermine any perceived cost benefits achieved and/or predicted during the design stage, and that factors such as the local climate always need to be taken into consideration.
The researchers recommended further investigation into other benefits of building schools to this standard, including comfort and the reduction in sick days, but highly recommended that the government build school buildings to the passive house standard on the basis of evidence gathered so far.