How to compare solar quotes without the jargon

Start with the same household information

Give every installer the same recent electric bills and describe expected changes such as an electric vehicle, heat pump, addition, or home efficiency project. Quotes based on different usage assumptions are difficult to compare.

Also consider your roof’s age, condition, shade, direction, and available area. If the roof may need replacement soon, resolve that plan before installing panels.

Normalize the system numbers

Create one line for each proposal and record the same core figures. Ask the installer to explain any number that is missing or materially different from another quote.

• System size in kilowatts (kW DC)
• Estimated first-year production in kilowatt-hours (kWh)
• Percentage of your annual electricity use the estimate is designed to cover
• Total cash price before incentives, plus cost per watt
• Panel, inverter, racking, battery, and monitoring model numbers

Question the production forecast

Estimated savings depend on how much electricity the system produces and how your utility values that electricity. Ask what weather data, shade analysis, panel degradation, utility rate changes, and export-credit rules are assumed.

• Request a roof layout showing panel placement and shaded areas.
• Compare the proposal with an independent estimate such as NREL’s PVWatts.
• Ask whether the production estimate is guaranteed and what the remedy would be.

Compare cash and financing separately

A low monthly payment can hide a longer term or a higher financed price. Ask for the cash price even if you expect to finance, then list the annual percentage rate, term, fees, total of payments, prepayment terms, and whether the payment changes over time.

For a lease or power purchase agreement, identify who owns the equipment, who receives incentives, how payments can escalate, and what happens if you sell the home or need roof work.

Read the installation and service scope

Confirm who is responsible for permits, utility interconnection, inspections, structural or electrical upgrades, monitoring setup, and final permission to operate. Ask who will service the system if the original salesperson or installer is no longer available.

• Installer workmanship warranty
• Manufacturer equipment warranties and exclusions
• Roof-penetration coverage
• Expected installation and interconnection timeline
• Removal and reinstallation terms if roof work is needed later

Do a final reality check before signing

Verify licenses, insurance, reviews, and references. Read the complete contract and financing documents without sales pressure. Incentives, tax treatment, utility programs, and interconnection rules change, so confirm current details with the relevant agency, utility, and a qualified tax professional.