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Box 8 Retrofitting the Suburbs
Many suburbs in developed nations are due for renovation. They may eventually face rede
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velopment as ecologically insensitve forms of infill. Some of these leaky (old and new) homes
guzzle fossil fuels and belch greenhouse gases. In urban areas, the total greenhouse gas emis
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sions and other impacts of buildings can be greater than those of transport. Replacing them
would involve extraordinary resource flows and, given current design norms, would entail
massive embodied and operating energy.
New, higher-density infill development has sometimes been a curious blend of the worst
aspects of consolidation and sprawl. It often reduces biodiversity, solar access, ecosystem
services and environmental amenity (ie views and landscaping). It often increases noise,
traffic, stormwater runoff and energy consumption. While many advocate reduced interior
and exterior living space, new homes in countries like the US and Australia are still growing
larger. However, most energy and material flows are not caused by space (which
in itself
does
not use or embody energy). Other factors, such as the
source
of energy (ie solar energy or
fossil fuels) or the
source
of materials (ie bio-based or extractive/non-renewable), can be more
harmful over the building life-cycle.
1
What matters is the use and design of space. Therefore, a partial material flows analysis was
undertaken in Canberra to determine which pattern of housing was preferable from a whole
systems and life-cycle perspective:
2
•
Urban ‘consolidation’ (ie increasing inner-city residential density)
•
Replacing dwellings with ‘green’ infill development
•
Green field energy-efficient development
•
Renovating the housing stock with energy-efficiency measures
The study indicated that one of the most efficient means of reducing energy consumption
and greenhouse gas emissions would be to retrofit the existing housing stock with passive
solar design features. Passive solar retrofitting could be achieved more rapidly and with less
resource flows and negative impacts than either ‘energy-efficient’ green field or urban infill.
Of course, councils like the new rates and taxes that green field development brings, but they
cannot afford to service new areas. While resource autonomous homes would solve this
problem, they would cause more green field development. Instead, existing buildings could be
retrofitted at net zero cost to homeowners by using financial mechanisms like performance
contracting (where contractors recover the cost of construction from the future energy
savings of the building).
3
Some local governments have established revolving funds for energy
retrofitting for their own buildings. However, given the systemic biases against the eco-ret
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rofitting of existing homes, a positive incentive may be needed.
The study therefore proposed that second storey units be permitted – but only where both
dwellings were converted to passive solar heating, cooling and ventilating [Box 9]. This would
provide the financial benefits of both rental income and increased capital value. It would
also increase suburban density with little increase in land coverage, and without disrupting
local communities. The demand on infrastructure would be reduced because the ‘resource
autonomy’ of both dwellings would be required.
4
An eco-retrofitting programme could:
•
Reduce greenhouse emissions, waste, resource use and energy consumption while
increasing the ecological base.
•
Upgrade the housing stock to increase longevity without the extensive demolition and
waste that accompany major re-developments.
•
Increase residential density, where appropriate, without exceeding the capacity of the
existing infrastructure, while generating surplus eco-services.
•
Convert suburbs from fossil-fuel dependency and toxic, petrochemical-based materials
to clean, safe and healthy passive solar energy systems and compostable materials.
•
Provide for responsible lifestyle choices, and preserve the life quality and ‘sense of
community’ that people seek in the suburbs.
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Positive Development
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