Solar Panel Degradation Calculator
Estimate solar panel output after years, remaining capacity, degraded kWh/year and lifetime energy loss from first-year and annual PV degradation rates.
☀️ Design Rule: Solar panels slowly lose output every year. Use this with the Solar Panel Temperature Loss Calculator, Solar Panel Efficiency Calculator, Solar Panel Output Calculator and Solar ROI Calculator.
📉 Solar panel degradation: rated output slowly reduces over service life
Panel Rated Power
System Size Optional
Panel Age
First Year Degradation
Annual Degradation After Year 1
Model Type
Use first-year light-induced degradation plus yearly degradation to estimate remaining solar panel output after the selected service years.
Presets:
System Size
Current Specific Yield
Analysis Period
First Year Degradation
Annual Degradation
Electricity Value Optional
Estimate annual and lifetime energy loss from PV aging. This is useful for ROI, payback and production guarantee planning.
Energy presets:
Panel Rated Power
Measured / Expected Power
Panel Age
Warranty at 25 Years
Warranty at 10 Years Optional
Warranty Shape
Compare an expected or measured panel output with a simple warranty-style remaining capacity curve.
Warranty presets:
📐 Formula Reference
Compound Degradation
Remaining = (1 - first%) × (1 - annual%)^(years - 1)
Panel Output After Years
Pyear = Prated × Remaining%
Annual Energy After Aging
kWhyear = kWdc × yield × remaining%
Energy Loss
Loss = no-degradation energy - degraded energy
📋 Quick Reference
Typical Annual Degradation
Premium N-type0.25–0.40%
Common mono0.45–0.70%
Harsh/older0.80%+
25-Year Remaining
Excellent90%+
Good84–89%
Older warranty80–83%
Main Causes
Heat & UVaging
Moisturecorrosion
Microcracksloss
📚 Design Notes
First year can be differentMany panels have a larger first-year degradation, then a smaller annual degradation rate after that.
Use warranty datasheet valuesFor real projects, use the manufacturer’s performance warranty values instead of generic defaults.
Degradation is not temperature lossTemperature loss is temporary while the module is hot. Degradation is permanent long-term aging.
Energy impact compounds slowlyA small yearly percentage looks minor, but over 20–30 years it can noticeably reduce lifetime kWh and ROI.
What is a Solar Panel Degradation Calculator?
A solar panel degradation calculator estimates how much output a PV module or full solar system may lose over years of operation. It helps estimate remaining wattage, degraded annual energy and lifetime energy impact.
How much do solar panels degrade each year?
Many modern solar panels degrade around 0.3% to 0.7% per year after the first year. Premium N-type panels may be lower, while harsh climates, poor ventilation and older modules can be higher.
How much power will a solar panel produce after 25 years?
Many performance warranties are around 80% to 92% of original rated output after 25 years. A 400 W panel at 85% remaining capacity would be approximately 340 W under standard test conditions.
Solar panel degradation vs temperature loss
Temperature loss happens only while the panel is hot, but degradation is permanent aging. Use the temperature loss calculator for hot-day output and this degradation calculator for long-term output over years.
❓ Frequently Asked Questions
Use the first-year degradation once, then apply the annual degradation rate for the remaining years. Example: 2% first year and 0.55% per year after that gives about 84.7% remaining after 25 years.
Around 0.25–0.40% per year is excellent. Around 0.45–0.70% per year is common for many standard panels. Higher values may be expected for older panels or harsh environments.
No. Most panels can still work after 25 years, but output is lower. The 25-year value usually refers to the performance warranty period, not the absolute end of life.
Common causes include UV exposure, heat, humidity, thermal cycling, microcracks, encapsulant discoloration, cell/interconnect stress and potential induced degradation in some systems.
Cleaning improves temporary soiling loss, but it does not reverse true module degradation. However, keeping panels clean and avoiding hotspots can help long-term performance.
Warranty curves are often simplified as linear or step guarantees, but real field degradation is not perfectly linear. This tool gives both practical compound and simple linear estimates.
Degradation reduces yearly energy production over time, so lifetime savings are lower than a no-degradation estimate. This matters for long-term ROI, payback and LCOE calculations.
Yes. Enter the full system size in kW and expected yield in kWh/kW/year to estimate yearly and lifetime energy impact from degradation.