Human Settlements Review - Parliamentary Monitoring Group

Human Settlements Review, Volume 1, Number 1, 2010
in the cells that you also include some quality
assurance testing to validate that the results
are still being calculated accurately.
Conclusion
To test the results that would be generated
by the calculator, we used actual data for
the Western Cape generated by Quantity
Surveyors. Fifteen sustainable building
interventions were assessed through the
calculator, measuring the capital costs, the
operating costs, and the environmental
impact of each. The findings of this process
confirm the conclusion of the original life-cycle
assessment case study in that sustainable
building interventions were proven to be
more cost effective over the full life cycle of a
housing development. Although this was again
as directionally important as the findings from
the first study, the result of an examination of
the break-even point of each of the individual
interventions was also highly illuminating.
Many of the interventions broke even over a
surprisingly short period of time even without
consideration of their environmental or health
impacts. The following are the highlights of
these findings:
1. The following interventions pay back
within one year of construction:
Hold-flush Toilets
CFL Bulbs
Aluminium Windows
Duplex - Shared Walls
Compressed earth blocks (If not
locally available, Block 90//90 are also
highly cost effective)
2. The following interventions pay back
within less than 15 years:
Low-flow Fixtures
Basin to feed cistern
Solar Water Heater
Efficient Design
Though ceilings and ceiling insulation were
not found to be particularly economical
interventions, the significant health and
comfort benefits they provide outweigh the
costs of the interventions.
Greywater Recycling is cost effective within
a 15 year horizon, but only on middle-income
housing that currently utilise potable water for
garden irrigation.
Though rainwater harvesting is not particularly
economical, it does provide environmental
benefits and in water poor areas should be
considered regardless of the costs.
In summary, our analysis revealed that nearly
all sustainable building interventions were
economic over the life cycle of a building.
If ecological benefits and savings to local
government are also calculated, the benefits
of implementing these interventions become
even more decisive.
With the use of the Sustainable Housing
Calculator, the long-standing debate on
the cost-effectiveness of sustainable vs.
conventional building interventions can finally
be examined objectively for improved decision
making.
Contact information at www.
sustainabilityinstitute.net).
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