Savings and payback

25 year lifetime savings calculator

Project your total savings across a full 25 year system life, factoring in both rising utility rates and gradual panel output decline.

For planning purposes only, not financial or tax advice; confirm figures with a licensed installer or tax professional before making a purchase decision.

Your numbers

1 Project details Optional
Shown on your exported report. Leave blank to skip.
2 Year one savings
Use the result from the solar savings calculator if needed.
3 Growth and degradation
Historical US residential rates rise about 2 to 3% a year on average.
Most manufacturers guarantee output through a 0.5% or lower annual decline.

How it works

Three steps to your lifetime total

Step 1

Start with year-one savings

Use the result from the solar savings calculator as your starting point.

Step 2

Pick a rate growth and degradation assumption

Rate growth increases your savings each year, while panel degradation slightly reduces output. Both compound over 25 years, so the net effect depends on which one is larger.

Step 3

Read your total and average annual savings

The tool sums 25 years of adjusted savings. For a full year-by-year table instead of just the total, see the year by year breakdown tool.

Understanding your lifetime savings

What a 25 year total actually shows

Starting from $1,800 in year-one savings, with 3% annual utility rate growth and 0.5% annual panel degradation, total savings reach about $61,365 over 25 years. That's meaningfully higher than the $45,000 you'd get from simply multiplying year-one savings by 25, since rate growth compounds faster than the modest yearly output decline. Utility rates drive the whole savings calculation, and the US Energy Information Administration's electricity data track them state by state.

Why growth usually outweighs degradation

Historical US utility rates have risen around 2 to 3% a year, while typical panels degrade only about 0.5% a year. That gap means most systems see rising real savings over time rather than flat or declining ones, even as physical output slowly drops. The degradation loss tool isolates that one factor if you want to see its effect on its own. If you have not sized the system yet, start with the bifacial panel output addon calculator and bring its kilowatt figure back here.

Why 25 years specifically

Most panel manufacturers back their products with a 25 year performance warranty, guaranteeing a minimum output level through that period. It's become the standard timeframe for solar financial projections, even though many systems keep producing well beyond it. See the 30 year version for a longer view. The US Department of Energy's homeowner's guide to going solar walks through the same decision step by step.

What this total doesn't include

This is a savings-only projection. It doesn't subtract system cost, financing costs, or maintenance. Pair it with the total cost of ownership calculator for a full net figure, or the ROI percentage calculator to express the return as a single percentage. The production figure behind this estimate comes from the real world vs nameplate output gap calculator, which models output for your location and roof.

Questions

Frequently asked

A system starting at $1,800 in year-one savings, with 3% annual utility rate growth and 0.5% annual panel degradation, totals about $61,365 over 25 years. That compares to just $45,000 if savings stayed perfectly flat, since rate growth outpaces the small yearly output decline.

Most solar panel manufacturers offer a 25 year performance warranty, guaranteeing a minimum output level through that period. Panels typically keep producing well beyond 25 years, but this is the timeframe most warranties and financial projections use.

Typical crystalline silicon panels degrade about 0.5% per year, meaning a system still produces roughly 88% of its original output after 25 years. This is a modest drag compared to the effect of rising utility rates, which usually outweighs it over the long run.

The math is identical, just extended five more years. Many panels installed today are rated to perform well past their 25 year warranty, so the 30 year version gives a more realistic view of total lifetime value for homeowners planning to stay long term.

Related tools

Keep exploring lifetime value

Lifetime savings, 30 year Break even timeline estimator Savings loss from degradation Year by year savings breakdown Total cost of ownership calculator ROI percentage calculator Solar vs no solar, 25 year All savings and payback tools