How to Read a Solar Quote (and Spot a Bad One)

1. Work out the price per watt

Total system price ÷ system size in watts (DC) = price per watt. A 7.2 kW system quoted at $25,200 is $25,200 ÷ 7,200 W = $3.50 per watt. This is the single best way to compare quotes for different-sized systems.

For reference, Berkeley Lab's median for homeowner-owned residential systems installed in 2025 was $3.60 per watt overall and $3.00 for cash purchases; the middle 60% of systems cost roughly $2.70 to $4.90 per watt. Our state pages show the median where Berkeley Lab reports one. Use the total before any incentives, and make sure it includes everything: permits, interconnection, any electrical panel upgrade, and monitoring.

2. Check the production estimate

Every quote should say how many kWh the system will produce in its first year. Divide that by the system size in kW to get kWh per kW. Compare it with the number on your city's page on this site, which comes from the National Laboratory of the Rockies' PVWatts model for a south-facing roof; the US median is about 1,371 kWh per kW.

• A quote well above that number for your area deserves a question — unless your roof is unusually ideal.
• A quote well below it may reflect shade or an east/west roof. That's honest, but it lengthens payback.

3. Check the savings assumptions

• Electricity price increase. Savings projections usually assume utility rates rise every year. We use 2.5%; projections built on 4% to 5% a year make the 25-year savings look far bigger.
• Export credits. Ask how the quote values power sent to the grid. In 18 states, exports earn well below retail; a quote that values every kWh at your full rate overstates savings there. See net metering vs net billing.
• Your usage. The system should be sized to your actual last 12 months of bills, not a guess.
• Tax credits. In 2026, a homeowner-owned system gets no federal tax credit. A quote for a purchase that still subtracts "30% federal ITC" is out of date or misleading.

4. Compare the equipment and warranties

• Panels: brand, model and wattage. Most quality panels carry a 25-year product and performance warranty.
• Inverters: one central (string) inverter, or microinverters / optimizers on each panel. Panel-level electronics cost more but handle partial shade better and come with longer warranties, often 20–25 years versus about 10–12 for a string inverter.
• Workmanship warranty: covers the installer's work, including roof penetrations. Ten years or more is a good sign.
• Battery, if any: usable capacity in kWh, power output in kW, and warranty years or throughput.

5. Read the financing carefully

If a quote includes a loan, ask for the cash price too. Loan-financed systems cost a median $4.50 per watt in 2025 versus $3.00 for cash, largely because lender fees are rolled into the price. For leases and PPAs, look at the annual escalator, the term and what happens when you sell the home — covered in our lease vs buy guide.

Red flags

• "Free solar" or "no-cost government program" pitches. These are leases or PPAs.
• Pressure to sign the same day, or a "discount" that expires tonight.
• No itemized price, no stated system size, or no first-year production number.
• A federal tax credit on a purchased system installed in 2026.
• Savings that assume full retail credit for exports in a net-billing state.
• Reluctance to put the roof's condition, the panel layout or the warranty terms in writing.

Then compare at least three

Put each quote's price per watt and first-year production side by side, then enter them into the calculator on your city's page to see each one's payback. Prices for the same home routinely vary by thousands of dollars, so the extra quotes are usually the best-paid hour you'll spend on the whole project.