Author
Sustainable Cambridge Homes has been prepared by Dr Geoffrey Stoneman. He has had a long career in applied scientific research and public-policy development. The six main pages are intended to remain balanced, resident-facing and evidence-based; the views on this page are his own.
Why I became involved
My interest in environmentally responsive housing goes back almost 50 years. As a student at the Australian National University in the 1970s, I studied climate change and developed an interest in passive-solar house design. That interest subsequently influenced the environmental design of my own home.
When I became aware that the Town of Cambridge was preparing an Environmentally Sustainable Design local planning policy, my initial reaction was positive. It was the kind of initiative I had wanted to see local planning address. I therefore approached the draft from a position of support for its broad environmental objective.
My concerns arose when I examined the detailed proposal. Over many years I have also seen the practical tension that can arise when planning controls prescribe conventional requirements while a particular site or an unconventional design may offer a different way of achieving a good environmental outcome. That experience reinforced my interest in whether the draft starts with clearly defined environmental outcomes and allows appropriate flexibility in how they are achieved.
That is why I decided to examine the draft and the evidence behind it more closely, and ultimately to prepare this website. The purpose of doing so is not to tell other residents what conclusion to reach, but to make the proposal, the existing regulatory context, the available evidence and the questions I think warrant consideration easier to examine.
My perspective on the draft policy
I support the objective of improving the environmental performance of new homes in Cambridge. My concern is not with that objective, but with whether the present draft has sufficiently established the problems it is trying to solve and whether its particular mix of mandatory measures and points is the best way to achieve worthwhile additional environmental benefits.
In my view, the published consultation material would be stronger if it explained more clearly what existing national, State and local requirements already achieve; the evidence for the mandatory technologies, thresholds and point values; the alternatives considered; and the expected additional benefits, costs and practical effects. I am also concerned that a checklist can encourage compliance by accumulating measures rather than starting with the integrated environmental performance of the particular site and dwelling.
I would prefer an approach that places greater emphasis on clearly defined environmental outcomes, climate-responsive design, workable alternative pathways, proportionality, and monitoring and review.
I have particular concerns about making a 3,000 litre rainwater tank or approved greywater system mandatory. The environmental result of these systems depends on matters such as roof catchment, connected uses, household occupancy, rainfall, installation and maintenance, and rainwater and greywater are not equivalent in their operation, costs or environmental effects. My concern is therefore with prescribing particular technologies and a uniform threshold before the intended environmental outcome, expected additional benefit and basis for the threshold have been clearly established. That does not mean every prescriptive measure is unsound. Some may be useful and easy to administer. The question for me is whether each requirement is justified by the problem and evidence, adds enough benefit beyond what is already required, and remains flexible as regulation, technology and knowledge change.
These are my conclusions, not the conclusions residents are expected to reach. The purpose of the main site is to provide information and questions that help residents form their own views.