A solar system is a 25-year investment in your home. The panels get most of the attention, but the company installing them matters just as much. A well-designed system installed by a sloppy crew can underperform for its entire life. A system installed by a company that folds three years later leaves you with no warranty support and no one to call when something breaks.
This guide covers what to look for, what to verify, how to compare quotes, and the warning signs that should make you walk away.
Installer vs. broker — know which one you are talking to
The solar industry has a significant number of sales organizations that present themselves as installers but do not actually install anything. They take your deposit, sell your job to a subcontractor, pocket a margin, and move on. When something goes wrong six months later, they may be hard to reach — or out of business entirely.
A true installer has licensed electricians and roofing-qualified crews on staff. They design the system, pull the permits, do the work, and handle the utility interconnection themselves. Before you go far with any company, ask directly: Do your own employees install the systems, or do you subcontract? A good installer will answer that question without hesitation. A broker will often deflect or give a vague answer.
Credentials to verify
Two credentials matter most:
- NABCEP certification. The North American Board of Certified Energy Practitioners (NABCEP) is the gold standard for solar installers. A NABCEP-certified installer has passed rigorous technical exams and completed documented installation experience. Not every good installer has it, but its presence is a strong positive signal. Search the NABCEP directory at nabcep.org to confirm certification is current.
- State contractor license. Most states require a licensed electrical contractor for solar installation. In California, that means a C-10 Electrical or C-46 Solar Contractor license. Other states have similar requirements. Ask for the license number and verify it yourself at your state's contractor licensing board website. An unlicensed installer is illegal in most states and leaves you with no regulatory recourse if something goes wrong.
Beyond these, confirm the company carries liability insurance and workers' compensation coverage. If a worker is injured on your roof and the company has no workers' comp, you may be liable. Ask for a certificate of insurance before work begins.
How to compare quotes
Get at least three quotes. Solar pricing varies enough between companies that a single quote tells you nothing about whether you are getting a fair deal. When comparing, focus on these specifics:
- Cost per watt. Divide the total system cost by the system size in watts to get a normalized price. A typical residential system in 2026 runs $2.50 to $3.50 per watt installed. Quotes significantly above or below that range deserve scrutiny — high quotes may include unnecessary add-ons, low quotes may reflect inferior equipment or a company cutting corners to win the job.
- Named equipment. Every quote should specify the exact panel model, inverter brand and model, and racking system. A quote that says "Tier 1 panels" or "high-efficiency inverter" without model numbers is not a quote — it is a placeholder. You cannot compare proposals without knowing what equipment each one includes.
- Production estimate. The quote should include an estimate of annual kilowatt-hour (kWh) production, usually modeled with software like PVWatts or Aurora. Compare this against your actual usage. If the production estimate seems too optimistic, ask how it was calculated.
- Warranty terms. You want three separate warranties: a panel product warranty (typically 10–12 years), a panel performance warranty (typically 25–30 years), and a workmanship warranty from the installer (typically 5–10 years). The workmanship warranty is the one most likely to matter — it covers how the system was installed, not just the equipment itself.
- Payment schedule. Standard practice is a deposit of 25–50% at signing, with the remainder due at system activation. Any company asking for full payment upfront should be treated with significant caution.
Local vs. national installers
Both have tradeoffs worth knowing.
Local installers typically know your utility's interconnection process, are familiar with local permit requirements, and have a reputation in the community they need to protect. They are often faster to respond to service calls because they are nearby. The risk with smaller local companies is financial stability — a small installer that closes leaves you without workmanship warranty support.
National installers like Sunrun, Sunpower, and Tesla Energy have more financial stability and name recognition. They tend to have more standardized processes and may offer more financing options. The tradeoff is that service can feel more remote, response times may be slower, and they sometimes use regional subcontractors for installation, which reintroduces the broker problem in a different form.
The best outcome is a local company with several years of operating history, strong recent reviews, and a track record you can verify. At minimum, check that a company has been in business for at least three years and has a physical address you can verify — not just a P.O. box or a virtual office.
Checking reviews and references
Reviews matter, but how you read them matters more. Focus on:
- Recency. Look at reviews from the past 12 to 18 months. A company can have a strong history and have quietly declined in quality. A pattern of recent complaints is more relevant than old praise.
- Volume relative to age. A company that has been in business for ten years but has only a handful of reviews is a yellow flag. Either they are not asking customers for reviews (which is unusual), or the reviews exist somewhere you are not looking.
- Specificity. Reviews that mention the crew by name, describe specific details of the installation, or reference follow-up service are more credible than generic five-star ratings with no content.
- How complaints were handled. Every company gets occasional negative reviews. What matters is whether the company responded, acknowledged the issue, and resolved it. Unresponded complaints are a worse sign than the complaints themselves.
For high-value projects, ask the installer for two or three references from customers whose systems are at least two years old. A two-year-old installation has been through seasonal changes, utility billing cycles, and at least one period where something minor may have needed attention. How the company handled that is more useful information than how smooth the initial install went.
Red flags that should make you walk away
- Pressure to sign today. "This price is only good until end of day" and "the incentives are about to expire" are classic high-pressure tactics. A 25-year investment deserves time to research and compare. Any company that won't give you that time is not a company you want on your roof.
- Vague or incomplete contracts. Your contract should name the specific equipment, installation timeline, payment schedule, permit responsibilities, and warranty terms. Blank spaces, TBD entries, or language you cannot understand are grounds to ask for revisions before signing — or to walk away.
- No local physical presence. A company operating out of a P.O. box or with no verifiable local address is harder to hold accountable if something goes wrong after installation.
- Unusually low bids. A quote significantly below the others usually means something: lower-grade equipment, unlicensed subcontractors, or a company that plans to cut corners and hope you do not notice. Low price is not inherently a red flag, but it warrants direct questions about how they achieved it.
- Charging for system monitoring. Most reputable installers include remote monitoring as a standard service. An installer who wants to charge extra for monitoring is either padding the bill or signaling that ongoing service is not their priority.
What to ask before you sign
Before you commit, get clear answers to these questions in writing:
- Who are your licensed electricians, and will your own employees be on site for installation?
- What is your NABCEP certification number, and can I verify your state contractor license?
- What are the exact make and model of the panels, inverter, and racking system?
- What is your workmanship warranty, and what does it cover?
- Who handles the permit applications and utility interconnection paperwork?
- What is the payment schedule, and what triggers each payment?
- What happens if the system underperforms relative to the production estimate in the proposal?
A good installer answers all of these without hesitation. Vague, deflecting, or incomplete answers to any of them are information worth acting on before you sign.