Solar panel cost guide: how to read and compare quotes
Prices vary a lot by state, roof, equipment and installer, so national "average cost" figures are a weak guide to your quote. The reliable approach is to get several written quotes and compare them on the same basis.
Compare on cost per watt
Divide the total price before incentives by the system size in watts (a 7.2 kW system is 7,200 W). This lets you compare quotes for different system sizes. For independent market data, Lawrence Berkeley National Laboratory publishes installed-price trends in its Tracking the Sun report.
What drives the price
- System size (kW) and how much of your usage you want to offset
- Panel and inverter type (string, microinverters, optimizers) and brand
- Roof type, pitch, condition and whether it needs repair first
- Electrical upgrades (main panel, meter), permitting and interconnection fees
- Battery storage, if included
- Financing costs: dealer fees on solar loans can be built into the price
Line items every quote should show
- System size in kW (DC) and estimated first-year production in kWh
- Exact panel, inverter and racking models
- Total price, and price after any incentives the installer is assuming (ask which ones and why)
- Workmanship warranty length, and panel and inverter warranties
- Who handles permits, utility interconnection and inspections
- Payment schedule (avoid large up-front deposits; the FTC warns about this)
Check production estimates yourself
Enter your address in NREL's free PVWatts calculator to sanity-check the installer's kWh estimate, then use our payback calculator.
Sources: U.S. DOE Homeowner's Guide to Going Solar; FTC: Solar Power for Your Home.