How to Vet a Solar Company: The Checks That Actually Matter

Quick answer: Online star ratings tell you almost nothing about whether a solar company will still be answering the phone in year eight. The checks that matter are the contractor licence, proof of insurance, the length of the workmanship warranty, whether the crew is in-house or subcontracted, and who handles service after the sale. Ask for references from installations three or more years old, not from last month.

What this guide covers

• The three warranties, and which one you will use
• Eight checks before you sign
• Green flags and red flags
• Reading reviews properly
• What happens if the company folds
• Common mistakes
• FAQ

The three warranties, and which one you will use

Every solar system carries three separate promises, from three different parties.

The panel warranty comes from the module manufacturer. It covers defects and guarantees a share of rated output over about twenty-five years.

The inverter warranty comes from the inverter maker, often for ten to twelve years with an optional extension.

The workmanship warranty comes from the installer. It covers the labour, the mounting, the wiring and roof penetrations.

The third one is the one you are most likely to need, and it is the only one that depends on the installer still existing. Roof leaks around mounting hardware are the classic claim, and no manufacturer covers those.

Workmanship terms in the market range from about five years to twenty-five. That spread tells you a lot about how confident a company is in its own crews.

Eight checks before you sign

1. Contractor licence. Look the number up in your state’s licensing database. Verify the name matches the entity on your contract, not a related trading name.

2. Insurance certificate. General liability and workers compensation. Ask for a certificate; do not accept a verbal assurance.

3. NABCEP certification. Ask whether a certified professional will be on your job and what their role is.

4. In-house or subcontracted. Neither is automatically bad, but if crews are subcontracted, ask who honours the workmanship warranty.

5. Years trading under this name. Companies in this sector rebrand often. Check the entity registration date, not the website copyright.

6. Old references. Ask for three customers from at least three years ago. Recent customers cannot tell you anything about service.

7. Who files the paperwork. Permits and utility interconnection should be the installer’s responsibility, in writing, with a stated timeline.

8. Service response. Ask directly what happens if the system stops producing in year six. Get the answer in writing.

Green flags and red flags

That last row is the one that costs the most money. See solar sales red flags for how dealer fees are buried in low advertised interest rates.

Reading reviews properly

Star averages are close to useless in this industry because most reviews are collected at installation, when everyone is happy.

Read the one and two star reviews instead, and look for patterns rather than individual anger. Repeated mentions of unanswered service calls, permit delays or billing surprises are the signal.

Check dates. A wall of five star reviews posted within one month is a campaign, not a track record.

Then check outside the review sites entirely. Search the company name against your state attorney general and consumer protection office. Formal complaints are a much stronger signal than star ratings.

What happens if the company folds

This happens regularly in residential solar, so plan for it rather than hoping.

Your equipment warranties survive. They are contracts with the panel and inverter manufacturers, not with the installer. Keep the model numbers and serial numbers somewhere safe.

Your workmanship warranty usually does not survive. That is the practical loss.

Your monitoring may stop working if it depended on the installer’s own portal rather than the manufacturer’s. Ask which platform your monitoring uses and make sure you hold the account credentials, not just the installer.

Finally, keep the full plan set, the interconnection agreement and the permit approvals. Another company can service a documented system. An undocumented one is far harder and more expensive to take over.

Common mistakes

Choosing on price alone. The cheapest quote often has the shortest workmanship warranty.

Not checking who actually installs. Sales companies and installation companies are frequently different businesses.

Skipping the roof conversation. A system installed on a worn roof costs thousands to remove and refit later.

Letting the installer own the monitoring account. Insist on being the account holder.

Not keeping documents. See warranty claims for the file you should build on day one.

FAQ

What is the most important thing to check?
The workmanship warranty length and who stands behind it, because that is the cover you are most likely to use and the one that disappears if the company does.

How many quotes should I get?
At least three, priced on the same system size and the same equipment class so they are genuinely comparable.

Does NABCEP certification matter?
It is a meaningful signal of technical competence. Ask specifically whether a certified person will work on your installation.

Are online reviews reliable?
Averages are not. Read negative reviews for patterns and check state complaint records separately.

What if my installer goes out of business?
Manufacturer warranties on panels and inverters continue. The workmanship warranty usually does not, so keep full documentation for a future service company.

Should the installer handle permits?
Yes, and it should be stated in the contract along with responsibility for utility interconnection.

Is a national brand safer than a local one?
Not necessarily. Several large national installers have failed. Long local trading history and in-house crews are better predictors.

Where to go next

Read how to get solar quotes, solar sales red flags and leasing versus buying before you meet any salesperson.

Consumer guidance is published by the U.S. Department of Energy and the Federal Trade Commission.