Balcony Solar Savings Calculator (by State and Kit Size)
Pick your state, kit size and where the panels will go. The estimate updates as you type.
How the estimate works
The calculator multiplies four numbers, then applies your electricity price:
Yearly kWh = usable kit power (kW) × typical yearly output per kW in your state × placement factor × (1 − shade)
- Typical output per kW is a rounded estimate of what a well-placed, tilted, south-facing system produces each year in the state's main cities, based on NREL PVWatts results. It ranges from about 1,150 kWh in Washington to 1,750 kWh in Arizona and New Mexico (Alaska is lower).
- Usable kit power is the smaller of the panel watts and the inverter limit plus 25%. Panels rarely reach their label rating, so a little more panel than inverter is normal; beyond that, the inverter caps the output.
- Placement factor reflects how much sun a panel loses when it hangs vertically or faces east, west or north. These are typical values for mid-US latitudes.
- Savings count only the electricity you use yourself, at your price per kWh. Read how much balcony solar really saves for worked examples by state.
Before you buy, check whether plug-in solar is allowed where you live on our state-by-state map, and read when it isn't worth it.
Frequently asked questions
How accurate is this calculator?
It gives a planning estimate, typically within 20 to 30 percent of what a real kit produces in an average year. The biggest unknowns are shade and how much of the power you use at home while the sun is shining. For a site-specific estimate, run the free NREL PVWatts tool with your exact address, tilt and direction.
Why does it ask how much power I use myself?
Most US plug-in solar laws exclude these kits from net metering, so electricity your home doesn't use at that moment flows to the grid without payment. Only the share you use yourself lowers your bill. A small kit in a home with a fridge, router and other devices running all day can reach 80 to 95 percent; a large kit in an empty apartment may be closer to 50 percent.
Where do the electricity prices come from?
The default price for each state is the average residential price for July 2026 from the U.S. Energy Information Administration (Electric Power Monthly, Table 5.6.A). Your own rate may be higher or lower, so replace it with the all-in price per kWh from your bill.