How to Choose a Solar Contractor: Vetting Steps and Questions to Ask

Choose a solar contractor by verifying the license and insurance, comparing at least three written proposals line by line, checking references and complaint records, and reading the contract's warranty and payment terms before you sign. The cheapest bid is rarely the best choice, because your system will operate for decades and the installer's workmanship, paperwork and willingness to answer warranty calls decide how well it performs. This guide gives you a repeatable process and the exact questions to ask. We do not rank or recommend companies.

Step 1: Build a shortlist

Start with three to five companies. Sources include:

• Neighbors with systems, whose real-world experience is valuable
• Your utility or state energy office, which sometimes lists participating contractors
• State solar associations and the NABCEP installer locator
• Local searches, then cross-checked with licensing boards
• Marketplace sites, which may charge installers for leads, so treat them as a starting point only

Be cautious with unsolicited door-to-door visits and pressure to sign the same day.

Step 2: Verify the basics

For each company on your list:

1. License. Look up the contractor on your state's licensing board website. Requirements vary by state; some require an electrical license, a general contractor license or a specialized solar classification.
2. Insurance. Request certificates showing general liability and workers' compensation coverage. A company without workers' compensation can leave you exposed if a worker is injured on your property.
3. Complaints. Search your state attorney general's consumer protection office and the Better Business Bureau. Patterns matter more than a single complaint.
4. Certifications. NABCEP (North American Board of Certified Energy Practitioners) offers voluntary professional certifications for solar installers. Certification is not legally required in most places, but it shows documented training.
5. Time in business and local presence. A company that has operated in your area for years is more likely to be around for warranty service, though a long history is not a guarantee.

Step 3: Request written, itemized proposals

Give each installer the same information: your last twelve months of electric bills, your roof photos and any shading concerns. Each proposal should state:

• System size in kW DC and number of panels
• Panel and inverter manufacturer and model
• Estimated annual production and how it was modeled
• Total price and price per watt
• What is included: permits, interconnection fees, electrical upgrades, monitoring
• Warranties on equipment, workmanship and roof penetrations
• Payment schedule and financing details

Compare using the quote checklist and the price-per-watt method in our cost guide.

Step 4: Compare proposals fairly

Illustrative example. You receive three proposals.

On price per watt, B and C tie at $2.90, but B is smaller. Dividing price by annual output: A = $24,800 / 10,900 = $2.28 per kWh; B = 22,040 / 10,100 = $2.18; C = 23,200 / 10,400 = $2.23. C is the cheapest but has a short warranty and no roof leak coverage stated. This table is invented. The point is that a fair comparison includes production and warranty terms, not just price.

Ask each installer to explain differences in estimated production, which often come from shading or tilt assumptions.

Step 5: Check references and past work

• Ask for three recent customers in your area and call them.
• Ask how long the project took, whether the crew was tidy, how the company handled issues and whether the system produces as promised.
• Ask to see a similar completed installation if possible.

Step 6: Understand who does the work

Many companies subcontract installation. That is not automatically a problem, but ask:

• Will your own employees or subcontractors do the installation?
• Who holds the electrical license for the job?
• Who is responsible for workmanship warranty if a subcontractor leaves?
• Who is the single point of contact for service?

Step 7: Read the contract carefully

Before signing, check:

• The scope of work matches the proposal exactly
• Total price and what could trigger a change order
• Payment schedule, preferably tied to milestones such as permit approval and final inspection rather than a large deposit
• Start date and expected completion timeline
• Cancellation rights and fees
• Warranty terms in the contract, not only in marketing brochures
• What happens if incentives or utility rules change before installation
• Dispute resolution, such as mandatory arbitration

Federal rules give certain buyers a short right to cancel home solicitation sales, and some states give more. The Federal Trade Commission explains the rule at its website.

Step 8: Plan for the long term

Ask what the company will do if it closes. Some installers offer warranty insurance or third-party backed warranties. Also keep copies of equipment warranties so you can contact manufacturers directly. See warranty and lifespan.

Mistakes to avoid

1. Choosing on price alone.
2. Signing under a "today only" discount.
3. Paying a large deposit before permits.
4. Accepting verbal promises that are not in the contract.
5. Not verifying license and insurance yourself.
6. Failing to check for red flags; see red flags in quotes.

Frequently asked questions

Is NABCEP certification required?

Generally not legally required, but it is a respected credential. Some programs or states may require or prefer certified installers.

How many quotes should I get?

At least three, from different companies, so you can see typical pricing and spot outliers.

Should I choose a big national company or a local installer?

Both types can do good or poor work. Evaluate licensing, references, warranty terms and service history rather than company size.

What if the installer wants a deposit?

Small deposits are common, but avoid large upfront payments. Tie larger payments to completed milestones, and check your state's rules, which can limit deposits.

Sources

• North American Board of Certified Energy Practitioners — certification and installer directory
• Federal Trade Commission — guidance on door-to-door sales and solar contracts
• U.S. Department of Energy — guidance on hiring a solar installer
• Better Business Bureau — business profiles and complaint history