How to read a solar quote line by line

By the Simple.solar editorial team. Reviewed October 2026. 7-minute read. How we research.

A solar quote can be ten pages of numbers, logos and charts. Most people skip to the monthly payment or the savings figure. That is exactly where the trouble hides. Two quotes for the same roof can look similar and still differ by thousands of dollars.

This guide walks you through each part of a typical quote, shows you the math to check it, and then compares three sample quotes side by side.

How do you calculate price per watt?

Price per watt ($/W) is the single best number for comparing quotes. It puts systems of different sizes on equal footing.

Price per watt = total price ÷ system size in watts

Say a quote lists a 7.2 kW system for $21,600. First convert kW to watts: 7.2 × 1,000 = 7,200 W. Then divide: $21,600 ÷ 7,200 = $3.00 per watt.

Use the gross price before any incentives so every quote is compared the same way. Many home systems in the US fall roughly between $2.50 and $3.50 per watt before incentives, though prices vary by region and roof. A quote well above that range should come with a clear reason, such as premium equipment or roof work.

Is the system the right size?

The quote should list the system size in kW (DC) and the number and wattage of panels. Check that they match: 18 panels × 400 W = 7,200 W, or 7.2 kW.

Next, compare the size to your use. Find your yearly kWh on your utility bills. A system usually should not produce much more than you use, since extra exports are often worth little. Our system size calculator gives you a target to compare against.

Is the production estimate realistic?

The production estimate tells you how many kWh the system should make in year one. This number drives every savings claim in the quote, so check it.

A simple test: divide the yearly production by the system size in kW. This gives you kWh per kW, sometimes called specific yield.

• 8,800 kWh ÷ 7.2 kW = about 1,220 kWh per kW.

Across most of the US, a well-placed system makes about 1,100 to 1,600 kWh per kW each year. Sunny Southwest states sit at the high end, and the cloudy Northwest and Northeast sit lower. NREL's free PVWatts estimates are a good reference point. If a quote in a cloudy state claims 1,700 kWh per kW, ask how they got it.

Shading

Look for a shade report or a "solar access" percentage for each roof face. A value of 95% means the panels get 95% of the sun they would with no shade. If there is no shade analysis at all, ask for one. Trees, chimneys and nearby buildings can cut output a lot.

What equipment is listed, and does it matter?

A good quote names the exact panel model, inverter model and racking. "Tier 1 panels" or "premium inverter" is not enough. With model numbers, you can look up spec sheets and warranties.

• Panels: Check wattage, efficiency, degradation rate and warranty terms. See our guide to solar panel types.
• Inverter type: String, microinverters or optimizers. Microinverters or optimizers cost more but handle shade better and add panel-level monitoring. A string inverter is fine for a sunny, simple roof.
• Battery (if included): Usable kWh, power output in kW and warranty length.
• Monitoring: Whether you can track output in an app.

What should you look for in financing terms?

Financing is where the biggest hidden costs live. Read this section slowly.

APR and dealer fees

Many solar loans advertise a low APR, such as 1.99% or 3.99%. To offer that low rate, the lender often charges the installer a dealer fee, which can be 15% to 30% or more of the loan. The installer then raises the system price to cover it.

Here is how that plays out. A system has a cash price of $21,600. With a 25% dealer fee built in, the loan amount becomes about $21,600 ÷ 0.75 = $28,800. You pay a low rate, but on $7,200 more than the cash price. Always ask, "What is the cash price, and what is the financed price?"

Escalators

Leases and PPAs often include an escalator, a yearly payment increase of 1% to 3.9%. A $140 payment with a 2.9% escalator grows to about $140 × 1.77 = $248 after 20 years. Check whether the escalator is higher than the utility rate increase the quote assumes.

Savings assumptions

Find the assumed yearly utility rate increase. Many quotes use 4% to 6%. A more cautious figure is 2% to 3%. Ask whether the savings include panel degradation and your utility's actual export rate. Our net metering guide explains why export rates matter so much.

What about roof work, permits and interconnection?

• Roof work: If your roof has less than 10 years of life left, replacing it first may make sense, since removing and reinstalling panels later can cost thousands. The quote should say whether roof work is included and who warranties it.
• Electrical upgrades: Some homes need a main panel upgrade, which can add $1,500 to $4,000 or more. It should be listed as a line item, and the work must be done by a licensed electrician.
• Permits and interconnection: The installer should handle building permits, inspections and the utility's interconnection application. Check that all fees are included.
• Timeline: Look for an estimated date for installation and for permission to operate (PTO) from your utility.

Total cost vs net cost

The total, or gross, cost is the full price before any incentives. The net cost is what you pay after rebates or credits.

Quotes often lead with the net cost because it looks smaller. Make sure each incentive listed actually applies to you. The US 30% homeowner tax credit (25D) ended for systems installed after December 31, 2025, so a quote that subtracts it for a new home install is wrong. For other programs, check current incentives in our incentives guide.

Worked example: comparing three quotes

Here are three made-up quotes for the same home, which uses about 9,500 kWh a year.

Here is the math behind the price per watt column:

• Quote A: $20,900 ÷ 7,200 W = $2.90.
• Quote B: $23,900 ÷ 7,700 W = $3.10.
• Quote C: $36,000 ÷ 9,000 W = $4.00, using the only price given.

Quote A is the cheapest per watt and uses honest assumptions. Its 8,800 kWh covers about 93% of the home's use. The string inverter is fine if the roof is sunny and unshaded.

Quote B costs $0.20 more per watt but adds microinverters, a 25-year workmanship warranty and output that matches use. Its financed price is $6,000 above cash, which points to a hidden dealer fee. Paying cash or using your own loan would avoid that.

Quote C has several red flags: no cash price, a 9 kW system for a home using 9,500 kWh, production of 1,500 kWh per kW that looks high for this area, a short warranty and a 6% rate increase. The extra 4,000 kWh it claims would likely be exported at a low rate.

For most buyers, A or B would be the stronger choice, depending on shade and how much the longer warranty is worth to you. Check any quote against our savings calculator, and see our guide to choosing an installer before you sign.

Frequently asked questions

Watch: a short explainer

Keep reading

• How much do solar panels cost in 2026?See 2026 solar prices per watt, total costs for 4 to 12 kW systems, where your money goes, battery prices and what pushes a quote up or down.5 min
• Solar incentives in 2026: what's left and whereThe US 30% homeowner credit is gone, but state credits, rebates, lease rules and programs in Canada, the UK, Australia and India still help.7 min
• Buy, loan, lease or PPA: how to pay for solarCompare paying cash, taking a loan, leasing or signing a PPA for home solar, with a worked 25-year example and the fine print that changes the math.7 min