Energy and life-cycle costs
Energy Retrofit NPV and IRR Calculator
Evaluate an efficiency project using savings, maintenance, incentives and replacement cost. Enter your own assumptions and local rates.
Calculate your result
What this calculator estimates
Evaluate an efficiency project using savings, maintenance, incentives and replacement cost. It combines the inputs below to produce Project net present value. Every assumption remains editable so the estimate can reflect the property, financing and location being evaluated.
Worked example
Using the displayed sample assumptions, the calculator produces $142,313. This is an illustration, not a market quote. Change one input at a time to understand what drives the result.
Inputs and assumptions
- Installed project cost — sample input: 150000 currency units
- Rebate or incentive — sample input: 20000 currency units
- Year 1 energy savings — sample input: 22000 currency units
- Annual maintenance savings — sample input: 4000 currency units
- Annual energy-price growth — sample input: 2.5 %
- Analysis period — sample input: 15 years
- Discount rate — sample input: 7 %
- Residual value — optional — sample input: 10000 currency units
How to interpret the result
Use discounted life-cycle costs and realistic equipment lives. Compare a conservative case with an expected case and keep a record of the assumptions used.
Common mistake to avoid
Do not evaluate an upgrade from simple payback alone. Local definitions, taxes, lending practices and measurement requirements can materially change the result.
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Reviewed 2026-09-08.