‘This is a wonderful book that should be on the desk of every architect and planner. It shows how

Sustainability
What kinds of stimuli could accelerate such retrofitting programmes?
The appropriate stimuli for direct action would depend on the scale of the eco-retrofitting programme.
There are a range of strategies and eco-solutions available [Figure 5]. A carrot for homeowners to 
consider individual retrofits would be free household audits and schematic design options, with 
estimations of their relative pay-back periods.
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Homeowners would be advised of options ranging 
from minor improvements through to whole-home retrofits, or even joint projects with residents of 
a whole neighbourhood through an existing progress association. For example:
•
A minimalist option might include insulation, draught-proofing and solar hot water heaters.
The full cost of this ‘lowest’ level of retrofit could be recovered from the energy savings of the
homeowner over, say, five years. As mentioned earlier, however, incremental and marginal
approaches can lead to ‘cherry picking’.
• 
The next level, a resource-autonomous option (again independent of external sources of
water, electricity and sewage treatment) would involve a combination of passive solar heating,
cooling and ventilation, photovoltaics, roof water collection and greywater treatment,
xeriscape gardens, arbours, atriums, greenhouse windows, and so on. It might only aim for
a payback of 10 to 20 years.
• 
At an even larger scale, existing suburbs could be converted to resource autonomy or better.
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This could be supported by credits for ‘ecological space’ that could be sold or traded to 
developers [Chapter 3 and 11].
• 
Finally, cities could be retrofitted to have net positive impacts on the region. Generally, we 
have only tried to predict and accommodate growth, rather than transform cities.
Funding or investment priorities to develop such programmes and/or partnerships would need to be 
established with a clear hierarchy of eco-innovations, as provided later [Chapter 14].