Getting solar quotes is the easy part. Every installer will give you a proposal - but most homeowners have no framework for comparing them. The quotes look different, use different metrics, and make different assumptions. This guide gives you what you actually need to evaluate them side by side.
Before comparing quotes, understand your baseline electricity usage. Pull 12 months of electric bills and find your average monthly kilowatt-hours (kWh). This number — not your square footage, not the size of your roof — determines how large a system you need.
A typical U.S. home uses around 900 kWh per month, which requires roughly a 7 to 8 kilowatt (kW) system. If a quote proposes a 5 kW system for that home, it's undersized. If it proposes 12 kW, ask why.
Every quote should include these — if it doesn't, ask for them.
System size in kW: The total generating capacity. Bigger isn't always better — you want the right size for your usage.
Estimated annual production in kWh: How much electricity the system is projected to generate per year. This should match your annual consumption reasonably closely.
Panel brand and efficiency rating: Efficiency ratings range from roughly 17% to 23%. Higher efficiency panels produce more power per square foot, which matters if your roof space is limited.
Inverter type: String inverters are cheapest. Microinverters (one per panel) cost more but perform better when any panel is partially shaded. Power optimizers are a middle ground.
Price per watt: Divide the total system cost by the system size in watts. This is your apples-to-apples comparison number across quotes. The national average runs around $2.50 to $3.80 per watt before incentives.
Payback period: How many years before cumulative savings equal your system cost. 7 to 10 years is typical. Be skeptical of quotes projecting 4-year paybacks.
Production guarantee: Reputable panel manufacturers guarantee panels will produce at least 80% to 90% of rated output after 25 years. Get this in writing.
The federal solar investment tax credit (ITC) allows you to deduct 30% of your total system cost from your federal taxes. On a $25,000 system, that's $7,500 off your tax bill — not a refund, but a direct reduction in what you owe.
You must have sufficient federal tax liability to use it. If you owe $3,000 in federal taxes this year, you can only use $3,000 of the credit (the remainder carries forward). Cash buyers and loan buyers both qualify. Lease and PPA customers generally do not — the installer takes the credit instead.
Many states also offer additional incentives. Search for your state's current solar incentives — they change frequently and vary significantly.
The lowest price per watt from an installer with no track record in your area is not necessarily the best deal. Workmanship and long-term support matter on a system you'll have for 25 years.
Search the installer's name plus your state and "reviews" or "complaints." Check their rating with the Better Business Bureau. Search whether their proposed panel brand has had any reliability issues. Search current federal and state incentive levels — these shift and some installers quote outdated numbers.