Calculator Overview97 2003
- 2. Sustainable Housing Calculator Why do we need a sustainable housing calculator? Compare conventional and sustainable building method costs Calculate the break-even point Identify funders and beneficiaries Calculate the ecological benefits of various interventions Compare various combinations of interventions for initial planning
- 3. Sustainable Housing Calculator Costing Requirements for the calculator: Capital expenses (up-front costs) land cost building cost for basic top structure civil services infrastructure (i.e. hookup costs for water/sewerage) electrical infrastructure (i.e. hookup costs for electricity) capital costs of sustainable interventions vs. conventional alternative (e.g. solar water geyser vs. electric water geyser)
- 4. Sustainable Housing Calculator Costing Requirements for the calculator: Operating expense (maintenance, usage charges) household rates/fees for electricity household rates/fees for water & sanitation household maintenance costs city maintenance costs for water/sanitation infrastructure maintenance costs for electrical infrastructure
- 5. Sustainable Housing Calculator Also inputted are the ecological benefits of the various possible interventions. KwH reduction of electrical use associated reduction in CO 2 emissions litres/yr of water consumption reduction litres/yr of sewer outflow reduction
- 6. Input Screen: This input screen is used to enter which sustainable interventions will be used in two potential development mixes for a project Allows comparison of development mixes with up to five types of housing User selects which sustainable interventions will be used in each of the scenarios being compared. The last few interventions have yet to be defined but will be added later in the project - For developments with only RDP housing, the input screen can be greatly simplified, bringing it down to just two columns of sustainable interventions that you choose from to compare the cost effectiveness over time
- 7. Funding and Costs: In this section you can define a list of potential funding sources. We have listed the most common ones and added another to cover other possibilities Users of the calculator can edit the cost assumptions to adjust to their local situation. For example, there may be a local supplier of solar water geysers that is cheaper so the cost here can be reduced - It is also possible to change the sources of funding depending on the individual development being considered
- 8. Development Costs: This area allows you to input the underlying land costs and the cost of the basic top structure and infrastructure costs as well as the funding source for each item There is a similar screen for Scenario 2 that is being compared against this scenario - There is a similar screen for inputting the Operating expenses for electricity, water, etc. Base Development Costs - Scenario 1 Cost Source of Funding RDP Land Cost/Unit R 6,000.00 Dept of Human Settlements Top Structure Cost/Unit - RDP R 45,000.00 Dept of Human Settlements Civil Services Infrastructure R 250.00 Municipality Electrical Infrastructure R 2,500.00 Municipality GAP Land Cost/Unit R 7,500.00 Dept of Human Settlements Top Structure Cost/Unit - RDP R 75,000.00 Dept of Human Settlements Civil Services Infrastructure R 250.00 Municipality Electrical Infrastructure R 2,500.00 Municipality GAP1 Land Cost/Unit R - Top Structure Cost/Unit - RDP R - Civil Services Infrastructure R - Electrical Infrastructure R - GAP2 Land Cost/Unit R - Top Structure Cost/Unit - RDP R - Civil Services Infrastructure R - Electrical Infrastructure R - MID Land Cost/Unit R 9,500.00 Dept of Human Settlements Top Structure Cost/Unit - RDP R 110,000.00 Dept of Human Settlements Civil Services Infrastructure R 250.00 Municipality Electrical Infrastructure R 2,500.00 Municipality
- 9. Output Screens: Output is now ready! A series of charts and a set of data tables are linked live to the input screens and immediately updated when the inputs are changed. This allows you to quickly compare the impact of leaving out or adding in a specific sustainable intervention Additional graphs will be created for electricity usage, water usage, sewage outflows, etc. - Also includes a household affordability index. This demonstrates the impact on the recipient household’s finances and alerts stakeholders to future affordability problems, e.g. If too much of income goes to electricity and water costs the city may end up with bad debts. CO2 Emissions
- 10. Sustainable Housing Calculator Potential uses for the calculator: Planning tool for developments – explore which interventions are most economic Planning tool for developments – explore which interventions have the most ecological benefits Make preliminary calculations to use when applying for additional funding from alternative sources – i.e. other governments, Eskom, carbon credits