Performance and output

Year 10 output estimator

Enter your stabilized year 1 output and annual degradation rate. See what your system should produce at the 10 year mark, and whether that falls within typical warranty terms.

Your system

1 Project details Optional
Shown on your exported report. Leave blank to skip.
2 Your system
Use your full-year, post-degradation-stabilized annual output as the starting point.
Used to show the dollar value of the year 10 output figure.
Check your panel's warranty document. Most modern panels fall between 0.3% and 0.6% per year.

How it works

Two steps to your year 10 estimate

Step 1

Get your year 1 stabilized figure

Pull your full-year output once past any initial degradation. Check the first year output estimator if you're still in your actual first calendar year.

Step 2

Enter your panel's degradation rate

This figure is usually stated directly on your panel's warranty document, often as a guaranteed maximum degradation curve. Compare against the output variance by panel brand tool if you're weighing panels from different manufacturers. That figure shrinks a little every year, and the panel degradation calculator projects the decline.

Understanding your year 10 output

How much output typically fades by year 10

At a typical 0.5% annual degradation rate, a system loses around 4.9% of its original output by year 10. A system that started at 10,500 kWh/year would produce roughly 9,987 kWh/year at the 10 year mark. This modest decline is a normal, expected part of every solar panel's operating life. A DOE assessment of federal PV systems models age-related degradation at roughly 0.5% per year as a standard planning assumption.

Why the math isn't a simple year times rate calculation

Each year's degradation applies to the previous year's already-reduced output, not the original starting point, so the losses compound slightly rather than simply stacking. This makes long-term degradation a bit gentler than a naive year-times-rate calculation would suggest, though the difference is small over a 10 year window. See the real world vs nameplate output gap calculator for how this fits alongside every other loss factor.

Finding the right degradation rate for your panels

Check your panel's spec sheet or warranty document for a stated annual degradation rate. Most modern panels fall between 0.3% and 0.6% per year, with premium panels often at the lower end of that range. Older panel technology from a decade or more ago sometimes carries a higher rate closer to 0.7% or 0.8%. Once you have a rate you trust, the 25-year lifetime savings calculator can turn that degradation curve into an actual dollar figure over the system's full life.

What to do if your output falls short of warranty expectations

Most manufacturer warranties guarantee at least 90% of original rated output through year 10. If your estimated output falls below that threshold, it may be worth having a professional evaluate the system, since a warranty claim could be appropriate. Compare your actual monitored production against this estimate to check where you stand. NLR's PV Fleet data, drawn from thousands of real installed systems, tracks how actual field performance compares against these kinds of warranty benchmarks over time.

What to do with this number next

Project further out with the year 25 output estimator, or see the full curve across the system's life with the 25 year output projection tool.

Questions

Frequently asked

At a typical 0.5% annual degradation rate, a system loses around 4.9% of its original output by year 10. A system that started at 10,500 kWh/year would produce roughly 9,987 kWh/year at the 10 year mark.

Each year's degradation applies to the previous year's already-reduced output, not the original starting point, so the losses compound slightly rather than simply stacking. This makes long-term degradation a bit gentler than a naive year-times-rate calculation would suggest.

Check your panel's spec sheet or warranty document for a stated annual degradation rate. Most modern panels fall between 0.3% and 0.6% per year, with premium panels often at the lower end of that range.

Most manufacturer warranties guarantee at least 90% of original rated output through year 10. If your estimated output falls below that threshold, it may be worth having a professional evaluate the system, since a warranty claim could be appropriate.

Related tools

Keep exploring your output

First year output estimator Year 25 output estimator 25 year output projection Real world vs nameplate output gap Output variance by panel brand Annual kWh output estimator Performance ratio calculator All performance and output tools