Three solar quotes, three different stories. Here’s how to compare them.
Nine numbers to line up so you can see which deal is really better.
- Compare cost per watt and expected yearly production, not just the monthly payment.
- Strip out any incentive you haven’t verified, especially the expired 30% homeowner credit.
- Check the assumptions behind every savings estimate.
General consumer information. Prices and equipment vary by region and installer. Get at least three written quotes before deciding.
Solar quotes rarely look alike. One leads with a low monthly payment, another with a big system, a third with a glossy 25-year savings chart. That makes them hard to compare, which isn’t always an accident. The fix is to pull the same nine numbers out of every quote and put them in one table.
Before you request quotes
Have 12 months of electric bills ready, know whether you’d pay cash or finance, and call your utility about its current net metering rules. Giving every installer the same information makes their quotes easier to compare. If you’re not sure your house is a good candidate, start with our solar fit checklist.
The 9 numbers to compare
1. System size (kW)
This is the total rated capacity of the panels, usually in kilowatts DC. Bigger isn’t automatically better; the right size depends on your usage and how your utility credits extra power.
Ask: How did you size this system from my usage?
2. Estimated yearly production (kWh)
This is what the system should actually generate in a year. Two systems of the same size can produce different amounts depending on roof direction, tilt, and shade. You can sanity-check estimates with the National Renewable Energy Laboratory’s free PVWatts calculator.
Ask: What shade analysis did you use, and does the estimate account for it?
3. How much of your usage it covers
Usually shown as a percentage “offset.” A quote covering 110% of your usage may make little sense if your utility pays little for exported power.
4. Total price before incentives
The full installed price, including permits, interconnection, and any electrical upgrades. Ask for the cash price even if you plan to finance.
5. Cost per watt
Divide the total price by the system size in watts. For example, a system priced at $24,000 for 8,000 watts works out to $3.00 per watt. This is the easiest way to compare quotes for different-sized systems. A much higher number deserves an explanation; a much lower one deserves a look at the equipment and warranties.
6. Equipment
Note the panel brand and model, and the inverter type: a single string inverter, microinverters on each panel, or optimizers. Microinverters and optimizers can perform better on partly shaded roofs and allow panel-level monitoring, but usually cost more.
7. Warranties
There are usually four, and they’re easy to confuse:
- Panel product warranty: covers defects in the panels.
- Performance warranty: guarantees panels keep producing a minimum share of their rated output over time.
- Inverter warranty: often shorter than the panel warranty, so check it separately.
- Workmanship and roof penetration warranty: covers the installer’s work and leaks where panels are attached.
Ask: Who honors the workmanship warranty if your company goes out of business?
8. Incentives the quote assumes
List every incentive the quote subtracts and verify each one yourself. In 2026, any quote for a system you’d own that subtracts a 30% federal tax credit is using an incentive that has ended. See what happened to the solar tax credit.
9. Financing terms and savings assumptions
For loans, note the APR, term, any dealer fee, and the total of payments. For leases and PPAs, note the escalator and the total over the full term. Then look at the savings chart and find the assumed yearly utility rate increase. Redo the estimate with no increase to see a conservative case. Our financing comparison explains each option.
A comparison table you can copy
| Line item | Quote A | Quote B | Quote C |
|---|---|---|---|
| System size (kW) | |||
| Yearly production (kWh) | |||
| Usage offset (%) | |||
| Total cash price | |||
| Cost per watt | |||
| Panels / inverter | |||
| Warranties (years) | |||
| Incentives assumed | |||
| Financing total / escalator | |||
| Rate increase assumed |
Beyond the numbers: the installer
- Valid contractor license in your state, and proof of insurance
- Installers with recognized training, such as NABCEP certification
- Who handles permits, inspections, and utility interconnection
- Expected timeline from signing to the system turning on
- Local references with systems at least a year old
- Complaint history with your attorney general and the Better Business Bureau
Common questions
How many quotes should I get?
At least three. Prices and equipment vary widely, and comparing several quotes is the most reliable way to spot an outlier.
Is the cheapest quote the best one?
Not always. Check that it uses comparable equipment, includes the same warranties, and isn’t relying on optimistic production or incentive assumptions.
Should I include a battery in the quote?
Ask for pricing with and without one so you can compare. Whether it’s worth it depends on outages and your utility’s rules; see who should buy a home battery.
What if quotes estimate very different production?
Ask each installer to explain its assumptions, and run your address through PVWatts. A quote that estimates far more production than the others for the same size system is a warning sign.
Sources: U.S. Department of Energy Homeowner’s Guide to Going Solar; National Renewable Energy Laboratory (PVWatts); North American Board of Certified Energy Practitioners (NABCEP). Updated October 2026.