How to Choose a Solar Installer: Licenses, Quotes, Warranties and Red Flags

How to choose a solar installer comes down to five checks: a valid license, certified and insured crews, a fair price per watt, clear warranties in writing, and no pressure to sign. Get at least three written quotes, compare them on the same terms, and pick the company whose design, contract and service record hold up best.

Price matters, but it isn't the whole decision. Your installer drills into your roof, wires a system to your electrical panel and is the first call when something goes wrong over the next 25 years or more. This guide walks through what to check, how to compare quotes fairly and which warning signs mean you should walk away.

What should you check before hiring a solar installer?

Start with the basics: the state license required for solar or electrical work, proof of insurance, certified professionals on the job, and a track record of installations near you. Then check who actually does the work, because some sales companies hand jobs to subcontractors you never meet.

Run through these checks with every company:

1. License. Look up the contractor's license on your state licensing board's website. California's Contractors State License Board offers a license check and a Solar Smart consumer page (opens in a new tab).
2. Certification. The Department of Energy's homeowner's guide (opens in a new tab) names NABCEP (opens in a new tab) certification as the industry standard. Ask whether the designer or crew lead holds it.
3. Insurance. Ask for proof of liability and workers' compensation coverage.
4. Who installs. Ask whether the company's own crews or subcontractors will be on your roof.
5. Track record. Ask for references from customers whose systems have been running for a few years.
6. Complaints. Search your state attorney general or consumer protection office for complaints.

How many quotes should you get, and how do you compare them?

Get at least three written quotes. The FTC recommends collecting several bids. Compare them on price per watt for similar system sizes, the equipment named, the production estimate and the warranties. Monthly payment is the least useful comparison, because a long loan or hidden fee can make an expensive system look cheap.

Price per watt is the system price divided by its size in watts. It lets you compare a 7.6 kW quote with an 8.0 kW quote. Cost per kWh over the system's life goes one step further, because it accounts for how much power each system will make. Our solar cost per watt calculator does both.

Here are three example quotes for the same home, at 1,350 kWh per kW per year and 0.5% yearly panel loss over 25 years:

Quote C is the largest system, but each kWh costs about 23% more than Quote A's. It could still win if it includes better equipment, a longer workmanship warranty or a needed electrical panel upgrade. Ask each installer to explain what is in the price so you compare like with like.

What a fair price looks like in 2026

Berkeley Lab's 2026 data update (opens in a new tab) reports a 2025 median of $3.60 per watt for homeowner-owned residential systems, $3.00 for cash purchases and $4.50 for loan-financed systems. About 60% of the 100 largest installers had medians under $4 per watt. Systems with a battery had a median of $4.90 per watt. Our guide to how much solar panels cost breaks those prices down further.

What should a solar quote include?

A complete quote names the panel and inverter makes and models, the system size, the estimated first-year production and how it was calculated, the cash price, any financing terms, every warranty, and who handles permits and utility approval. If any of these is missing, ask for it in writing.

Pay special attention to the production estimate. A good installer can tell you what model it used, such as NREL's PVWatts (opens in a new tab), now run by the National Laboratory of the Rockies, and what shading and orientation assumptions went in. If a quote's estimate is far higher than the others for the same roof, ask why.

The Treasury Department's consumer advisory (opens in a new tab) suggests asking how many kWh per month the system will produce compared with your use, how to avoid buying more panels than you need, and what the cost per watt is. Get all documents in a form you can keep.

What should you ask during the site visit?

The site visit is where a good installer shows its work. Expect someone to inspect your roof, measure shade, check your electrical panel and ask about future plans such as an EV or a heat pump. Use the visit to ask how they will design, attach and wire the system.

Good questions to ask in person:

• Is my roof ready? Ask how many years it has left. The DOE advises considering your roof's age before installing, because removing and reinstalling panels later adds cost.
• How will you handle shade? Ask which roof faces they will use and how much output they expect to lose to trees or nearby buildings.
• Does my electrical panel need an upgrade? If yes, get the cost as a separate line.
• How will the panels attach? Ask about flashing and sealing at each roof penetration and who fixes a leak.
• Should I add a battery? A good answer depends on your utility's export rules and outage history, not on a sales target.

A quick comparison sheet helps once the quotes arrive. Fill in one column per installer:

If one company can't fill a row, that is useful information too. A missing production method or an unverified license is a reason to keep looking.

Which warranties should you look for?

You want four protections in writing: the panel product warranty, the panel performance warranty, the inverter warranty and the installer's workmanship warranty. The last one covers leaks, roof penetrations and wiring, and it is only as good as the company behind it.

Ask these questions for each warranty:

• How long does it last, and does it cover parts, labor or both?
• Who honors it if the installer goes out of business?
• Does it transfer to a buyer if you sell the house?
• What voids it, such as roof work by another contractor?
• How do you file a claim, and how fast is the response?

Warranties also tie into how long your system will last. Our guide to how long solar panels last explains which parts usually wear out first. If you finance the system, the Treasury advisory suggests checking whether you can pay off the loan while the panels are still under warranty.

What should be in the contract?

The contract should match the quote: same equipment, price, size and production estimate, plus a project timeline, payment schedule, permit and interconnection responsibilities, warranty terms and your cancellation rights. Nothing you were promised verbally counts unless it is written in.

Watch the payment schedule. A reasonable contract ties payments to milestones such as permit approval, installation and final inspection, rather than demanding most of the money up front. The FTC's solar guide (opens in a new tab) warns against demands for cash and against signing before you have reviewed the paperwork.

Your contract should also give you cancellation rights. The FTC's Cooling-Off Rule (16 CFR Part 429 (opens in a new tab)) gives you until midnight of the third business day to cancel many sales made at your home for $25 or more. Some states add more time.

In California, the CPUC recommends that solar providers hand out the California Solar Consumer Protection Guide (opens in a new tab) at first contact. Interconnection applications for contracts signed on or after December 15, 2026 must include Version 4 of the guide. Read it before you sign.

What are the red flags when choosing an installer?

Walk away from same-day pressure, savings that sound too good, demands for large cash deposits, claims of a government program that pays for solar, and 2026 quotes that still subtract a 30% federal credit for a system you would own. Each is a sign the company is selling harder than it is designing.

The Treasury advisory lists high-pressure tactics, exaggerated savings and claims of "free" products as major red flags, and says anyone claiming the federal government pays for your solar is running a scam. The CFPB's 2024 Issue Spotlight (opens in a new tab) found that savings claims were often overstated and that loan prices often hid dealer fees.

For a longer list of warning signs, see our guide to solar sales red flags. If a company offers financing, read our guide to how solar loans work before you compare its terms with a bank or credit union.

What happens after you sign?

A good installer manages the whole process: site survey, final design, building permits, installation, inspection and the utility's interconnection approval. You shouldn't turn the system on until the utility grants permission to operate. The installation itself is usually the shortest step; permits and utility approval often take longer.

Ask for a timeline with each step and who is responsible. Keep copies of the permit, the final inspection sign-off, the interconnection approval and the completion certificate. You will need them for warranty claims, for any state incentive applications and when you sell the home.

Once the system is running, compare its first few months of production with the estimate in the quote. Our solar panel cost calculator and output tools help you check whether the price and performance match what you were promised.