CO2 Savings Calculator
How much CO2 do your solar panels save? Enter your annual production — see tons offset, trees equivalent, and miles not driven.
How to Use This Calculator
Enter annual solar production
Input how many kWh your solar system produces per year. You can find this in your inverter monitoring app (SolarEdge, Enphase, Fronius), your utility's net metering statement, or use our Solar Panel Output Calculator to estimate it. A typical 8 kW system in an average US location produces about 11,000-12,000 kWh/year.
Set your grid emission factor
The emission factor (lbs CO2 per kWh) represents how carbon-intensive your local electricity grid is. Every kWh your solar produces replaces a kWh from the grid — and the dirtier the grid, the more CO2 you're avoiding. The US national average is 0.386 lbs/kWh, but it ranges from near-zero in hydro-heavy states to over 1.5 lbs/kWh in coal-dependent states.
Use scenario presets
Not sure of your production? Click a scenario — Small (5,000 kWh), Average (10,000 kWh), Large (16,000 kWh), or Commercial (35,000 kWh) — to see CO2 savings for that production level. These represent realistic annual outputs for different system sizes in average US conditions.
The Formula
The tree equivalence uses the EPA's figure of ~48 lbs (22 kg) of CO2 absorbed per mature tree annually. The miles figure assumes the EPA average of 0.891 lbs CO2 per vehicle mile. Forest acres use 2.5 tons CO2 sequestered per acre per year — a common US forestry estimate.
Example
The Chen household — Columbus, OH
The Chens installed a 9 kW system that produces 10,800 kWh/year according to their Enphase monitoring app. Ohio's grid runs primarily on natural gas and some coal, with an emission factor of about 0.48 lbs/kWh.
Result
Over 25 years, the Chens' system saves 58.8 tons of CO2 — equivalent to never driving a car for nearly 15 years, or planting and maintaining 2,700 trees.