The formula is free.
The decision still needs evidence.
Put two supplier/project scenarios on the same nominal-currency assumptions. Compare net upfront cost, simple payback and low/base/high NPV while keeping engineering performance, incentives and actual savings outside the calculator until a qualified reviewer verifies them.
Two-project capital comparison
Entered-case comparison
| Project | Net upfront | Payback | NPV low | NPV base | NPV high |
|---|
Evidence and approval questions
Formula: NPV = −(capital − verified incentive) + Σ[(energy savings scenario + maintenance savings) × (1 − degradation)^(year−1) ÷ (1 + discount rate)^year]. No escalation, tax, financing or residual value is included.
Capital-decision boundary: this tool does not estimate engineering savings, equipment life, utility rates, incentives, tax, financing, installation scope or performance. Energy savings are not directly measurable; establish a baseline, assumptions and proportionate measurement-and-verification plan with qualified reviewers. Entered NPV is a scenario, not guaranteed savings or investment advice.
$12 project decision memo
Spend one report credit to export the two-project comparison, low/base/high cash-flow assumptions, delay scenario, missing evidence, approval questions and post-installation measurement baseline.
- Transparent simple payback and low/base/high NPV
- Assumption, quote-scope and uncertainty register
- Wait / approve / revise questions and owner record
- Proportionate baseline and post-installation M&V outline
Official calculators, uncertainty and M&V substitutes
PMF pre-judgment 83/100 · 60 days + 150 qualified visits before a behavioral verdict