Formula
Payback years = (project cost − incentives) ÷ (annual energy savings + annual maintenance savings)
What the result means
The main result summarizes the entered project scope, while the secondary figures expose the components behind it. Treat the estimate as a consistent comparison baseline and investigate any large difference between this result and a contractor proposal.
Actual requirements can change with field measurements, structural conditions, code, product instructions, disposal rules, taxes, labor practices, and the final contract scope.