What to ask before signing a solar quote
Get three quotes, and compare them on price per watt — not on monthly payment. The spread on identical systems is routinely 30–40%, which is a bigger lever than any equipment choice you will make. These are the questions that expose the difference.
Normalise every quote first
Divide total price by system size in watts. A $21,000 quote for 7 kW is $3.00/W; a $19,000 quote for 6 kW is $3.17/W and is the more expensive one despite the smaller number. The 2026 US average is around $2.85/W before incentives.
The twelve questions
- What is the cash price, and the price per watt? Before any financing discussion.
- Which net metering tariff will I be on, specifically? Not "you'll get net metering" — the tariff name. It drives your return more than the hardware. Why →
- What annual production do you estimate, and from what model? Ask for the shading analysis, not a rule of thumb.
- What degradation rate did you assume? Anything under 0.5%/yr is optimistic.
- What electricity price inflation did you assume? Above 4%/yr is flattering the numbers.
- Who warranties the roof penetrations, and for how long? Leaks are the expensive failure and they are workmanship, not equipment.
- Is the inverter replacement in your projection? String inverters need replacing around year 12–15 at $1,500–3,000. Many projections quietly omit it.
- Are you the installer or a sales dealer? Dealers subcontract; you want to know who actually gets on the roof, and who you call in year six.
- Is my electrical panel adequate, or is an upgrade needed? A service upgrade is $2,000–4,000 and is a common surprise.
- What happens if production falls short of your estimate? Some offer a production guarantee. Most do not — worth knowing which.
- What is the workmanship warranty, separate from the equipment warranty? 10 years is good, 5 is thin, 25 is marketing.
- What is the total cost if I cancel after signing? Ask before signing, not after.
Red flags
- "This price is only good today." Nothing about solar pricing is genuinely time-limited. This is pressure, not a deal.
- A quote with no shading analysis. If they have not looked at your roof, they are guessing at your production.
- Reluctance to give the cash price. Points to margin buried in financing.
- Claims of "free solar." It is a lease or a power purchase agreement. You are trading most of the savings and complicating a future sale.
- Assumed electricity inflation of 5%+. Makes any system look good on a 25-year chart.
- Door-to-door with same-day signing. Legitimate installers are happy to wait a week.
Before the first call
Know roughly what your roof can hold and what it should cost, so you can tell a fair quote from a padded one. Run your address through our checker → It uses Google's aerial imagery, so the shading figure is measured rather than estimated.
What this looks like in real cities
Measured rooftop data, spanning the range from fastest to slowest payback we have found:
| City | Sun hrs/yr | Rate | Payback |
|---|---|---|---|
| Boston, MA | 1,446 | 30.1¢ | 5.4 yrs |
| Ann Arbor, MI | 1,402 | 19.1¢ | 8.9 yrs |
| Virginia Beach, VA | 1,513 | 14.2¢ | 10.9 yrs |
| Salem, OR | 1,398 | 12.4¢ | 13.7 yrs |
| Montreal, QC | 1,384 | 7.9¢ | 30.7 yrs |
Frequently asked
How many solar quotes should I get?
Three, from independent companies. The routine 30-40% spread on identical systems makes this the highest-value hour you will spend on the project.
Should I use a national company or a local installer?
Local installers are often cheaper and easier to reach for warranty work; national companies may outlast them. Ask how long they have operated and who services the system if they close.
Is solar financing worth it?
Cash returns the most. Financing can still make sense if the loan rate is below what the savings earn, but compare the cash price first - financing often conceals a higher system price.
Related guides
General information, updated 2026-08-22. Not financial, tax or engineering advice.