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Solar ROI Calculator

Work out the return on investment and payback period of a solar installation.

About Solar ROI Calculator

Simple payback divides the up-front cost by the recurring annual benefit to get the number of years before the solar installation has paid for itself. Everything after that point is net gain, which the lifetime figures make explicit. Payback is the first screen most buyers apply: a system that pays back inside its warranty period is a very different proposition from one that does not.

Formula

Solar ROI

Payback (years) = Total installed cost ÷ annual annual bill saving

Total installed cost
Up-front cost
Annual bill saving
Recurring saving or return per year

Worked example

With the default values below, Solar ROI Calculator returns Payback Period of 7.83. Change any input above and every figure here is recalculated in your browser.

Inputs used

Total installed costminimum 0
9,000
Annual bill savingminimum 0
1,150
Expected lifeaccepts 1–60 years
20 years

Results

Payback Period
7.83 years
Payback Period
93.9 months
Lifetime Saving
$23,000.00
Net Lifetime Benefit
$14,000.00
Lifetime Return
155.6%

Step by step

  1. 1Values used
  2. 2Solar ROI
  3. 3Payback Period= 7.83 years
  4. 4Payback Period= 93.9 months
  5. 5Lifetime Saving= 23,000.00
  6. 6Net Lifetime Benefit= 14,000.00
  7. 7Lifetime Return= 155.6

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation or tax into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Solar ROI calculated?

Payback (years) = Total installed cost ÷ annual annual bill saving Simple payback divides the up-front cost by the recurring annual benefit to get the number of years before the solar installation has paid for itself. Everything after that point is net gain, which the lifetime figures make explicit.

Why does Solar ROI matter?

Payback is the first screen most buyers apply: a system that pays back inside its warranty period is a very different proposition from one that does not.

What values do I need to enter?

This calculator takes 3 inputs: Total installed cost, Annual bill saving, Expected life. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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