How to Compare Solar Quotes: A Step-by-Step Checklist

To compare solar quotes fairly, turn each one into the same few numbers: price per watt, lifetime cost per kWh, a production estimate you have checked yourself, and the true cost of any financing. Then compare equipment and warranties line by line, and screen for red flags. Quotes vary enormously. In 2025, median prices across the top 100 U.S. installers ranged from $2.40 to $6.30 per watt, according to LBNL. This checklist shows how to separate a good deal from a good pitch. You can enter everything into our compare quotes tool.

Step 1: Get quotes you can actually compare

Ask every installer for the same items, in writing:

• Total price before incentives. No “net price after tax credit.” There is no federal credit for an owned system installed in 2026.
• Cash price, even if you plan to finance. This is the only way to see a dealer fee.
• System size in DC kW, plus the number of panels and their wattage.
• Equipment make and model numbers for panels, inverters or microinverters, racking and any battery.
• Estimated first-year production in kWh, and the assumptions behind it (tilt, direction, shading).
• Design layout showing where the panels go.
• All warranties, as documents, not just a sales sheet.
• Payment schedule, including how much is due before installation and before permission to operate.
• Who installs: the company’s own crews or subcontractors.
• Itemized extras: main panel upgrade, roof work, trenching, permits.

Try to get quotes for similar sizes. If one installer proposes 6 kW and another 11 kW, ask each to price both, or use our system size calculator to settle on a target first.

Step 2: Normalize to price per watt

Price per watt = total price before incentives ÷ DC watts

Calculate this for every quote using the cash price. As of October 2026, about $2.60 to $3.00 per watt is a good cash price for a typical home, and over $3.50 needs an itemized reason. Small systems and complex roofs cost more per watt. See what is a good price per watt.

Price a battery separately, per kWh of storage. EnergySage’s H1 2026 median was about $1,130 per kWh.

Step 3: Check the production estimate

Price per watt ignores how much power you will actually get. A cheaper system on a shaded roof can produce less than a pricier one designed well.

Check each estimate against PVWatts, the free model from the national lab formerly known as NREL. Our production checker runs it for you. Enter the same size, tilt and direction the installer used.

How to read the comparison:

• Within about 10% of PVWatts: reasonable.
• More than about 10% above PVWatts: ask why. Common causes are ignored shading, a wrong roof direction, no allowance for losses, or optimistic weather data.
• Below PVWatts: often a sign of a careful installer who modeled shade on site.

As a rough sense check, one kW of well-placed panels produces about 1,100 kWh a year in the cloudy Northwest and 1,600 kWh or more in the Southwest. See inflated production estimates.

Step 4: Compute lifetime cost per kWh

This is the single best number for comparing quotes with different sizes and equipment. It tells you what each kWh from the system really costs.

Lifetime cost per kWh = (price + expected replacement costs) ÷ total kWh over 25 years

To get 25-year output, multiply first-year production by about 23.6. That accounts for panels losing about 0.5% of output a year.

Example: two quotes for the same home

	Quote A	Quote B
System	8.0 kW, string inverter	8.6 kW, microinverters
Price	$24,000 ($3.00/W)	$27,950 ($3.25/W)
First-year production (checked)	10,400 kWh	11,180 kWh
Expected inverter replacement	$2,500	Covered by 25-year warranty
25-year output	About 245,000 kWh	About 263,000 kWh
Lifetime cost per kWh	About 10.8¢	About 10.6¢

Quote B looks more expensive per watt, but it produces more and avoids a likely inverter replacement, so its lifetime cost per kWh is slightly lower. Compare that number to what you pay the utility per kWh and to what your exports earn.

Our compare quotes tool calculates this automatically.

Step 5: Compare the equipment

Look up every model number. You want:

• Panels from a financially stable manufacturer with a U.S. presence. “Tier 1” is a bankability list, not a quality rating. See no model numbers or “Tier 1” and best solar panels.
• Inverters suited to your roof. Microinverters or optimizers help with shade and multiple roof directions. See microinverters vs string inverters.
• A contract that names the equipment and does not allow substitution of “equivalent” products without your written approval. See equipment substitution.

Check our equipment guides for brand background.

Step 6: Compare the warranties

There are five separate warranties, and sales pitches often blur them together. See misleading warranties and solar panel lifespan and warranties.

Warranty	Who backs it	What to look for
Panel product	Manufacturer	Covers defects. 25 years is common on current panels
Panel performance	Manufacturer	Guarantees output stays above a level, often around 85% to 90% after 25 years
Inverter	Manufacturer	String inverters often 10 to 12 years (extendable); microinverters often 25 years
Workmanship	Installer	Covers installation errors, wiring and leaks. 10 years or more is a good benchmark
Roof penetration	Installer (sometimes roofer)	Covers leaks where the mounts go through the roof. Get it in writing
Production guarantee (optional)	Installer or financier	Pays if output falls short. Often pays a low rate per kWh over multi-year periods

Questions to ask:

• Does the manufacturer warranty cover labor to remove and replace a failed part, or only the part?
• Who honors the workmanship warranty if the installer closes? Several large companies, including the original SunPower, Sunnova and Freedom Forever, went bankrupt in 2024 to 2026, and many workmanship warranties went with them. See installer bankruptcy risk.
• How is a production shortfall measured and paid? See weak production guarantees.

Step 7: Compare the true cost of financing

If you are financing, compare total cost over the life of the loan, not the monthly payment.

• Dealer fees: the difference between the cash price and the financed price. The CFPB found these typically run 10% to 30% of the cash price. Use our dealer fee calculator.
• APR and term: a long term lowers the payment but raises total interest.
• Re-amortization: check whether the payment rises if you do not make a lump-sum paydown around month 18. That structure assumed a tax credit that owned systems no longer get. See re-amortization balloon.
• When payments start: payments that begin before the utility grants permission to operate mean you pay for solar and the full utility bill at once. See payments before PTO.

For leases and PPAs, compare total payments over the full term including the escalator. A 2.9% yearly escalator nearly doubles the payment by year 25. See solar financing options and the lease vs buy tool.

Step 8: Screen for red flags

Walk away, or at least slow down, if a quote:

• Subtracts a 30% federal tax credit for an owned system in 2026. See claims of a 30% tax credit.
• Promises a $0 electric bill. Fixed charges and export rules make that rare. See zero electric bill promise.
• Assumes rates rise 5% or more every year.
• Shows only a monthly payment.
• Has no model numbers or no roof assessment.
• Is sized far above your 12-month usage, especially under net billing. See oversized system.
• Comes with “today only” pricing or pressure to sign on a tablet. See today-only pricing and tablet signing rush.
• Calls a lease a “purchase” or a “program.”

You can paste specific claims into our sales claim checker. For the full list, see red flags and solar scams.

Step 9: Check the installer

• License: look up the contractor license on your state page.
• Own crews or subcontractors: sales-only companies dilute accountability. See sales-only subcontractors.
• Track record: how long in business, who services the system if they close, and complaints with your state attorney general.
• Reviews: be skeptical of “best installer” rankings that are paid placements. See fake reviews and rankings.

Our installer directory lists bankruptcies and enforcement actions we know about.

Bottom line: The best quote is not always the cheapest one. It is the one with a fair price per watt, a realistic production estimate, the lowest lifetime cost per kWh, named equipment, solid warranties from a company likely to survive, and financing whose total cost you understand.

Before you sign

• Read the whole contract, not a summary on a tablet.
• Know your cancellation window. The federal rule gives 3 business days for most door-to-door sales, and some states give more. See cancel a solar contract and our cancellation tool.
• Confirm the final numbers make sense in the calculator.