In short: To choose a solar installer, verify their licenses and certifications, get at least three itemized written quotes, check reviews and local references, compare warranties and who backs them, and avoid high-pressure sales tactics. The installer often affects your system’s performance and your long-term experience more than the brand of panel you choose.
A solar system is a 25-year commitment installed by a company you may need to call again in year 5 or year 15. A great installer with mid-range equipment usually beats a poor installer with premium equipment. This guide gives you a step-by-step process, a credentials checklist for the US and UK, a list of questions to ask, and the red flags to walk away from.
Why the installer matters so much
- Design quality: orientation, string layout, shading analysis and inverter sizing all affect production. See Best Roof Direction and Angle.
- Installation quality: wiring, roof penetrations and flashing affect safety and leaks.
- Paperwork: permits, inspections and utility interconnection can be slow or go wrong.
- Warranty support: a warranty is only as good as the company that helps you use it.
- Longevity: if the installer disappears, you may have no one to call about the system.
Step-by-step: how to choose a solar installer
1. Know what you want before you call
Gather your last 12 months of electricity bills and note your roof type, shading and goals (bill savings, backup power, EV charging). Understand the basics from How Does a Home Solar System Work? and How Many Solar Panels Do I Need? so you can judge what installers propose.
2. Build a shortlist of 3–5 installers
- Ask neighbors, friends and local community groups who have solar.
- Use official or industry directories in your country (see the credentials table below).
- Check independent review sites and local complaint records, not just the installer’s own website.
- Prefer companies with a local presence and a track record of several years.
3. Verify credentials before you invite anyone to your home
Check licenses, certifications, insurance and, if relevant, consumer-protection scheme membership on the official body’s own website.
| What to check | United States | United Kingdom |
|---|---|---|
| Business license | State or local contractor license (electrical and/or general, depending on state) | Registered company (check Companies House) |
| Industry certification | NABCEP-certified professionals on staff are a strong signal | MCS certification (needed for SEG export payments) |
| Consumer protection | Local and state consumer agencies; check for complaints | RECC or HIES membership, with insurance-backed guarantees |
| Insurance | General liability and workers’ compensation | Public liability and employer’s liability |
| Manufacturer status | Authorized or certified installer for the brands they use | Approved installer for the brands they use |
Requirements and names vary by state and country, so confirm what applies where you live.
4. Get at least three written quotes, with a site visit
Be wary of anyone who gives a precise quote without inspecting your roof and electrical panel (or reviewing detailed photos and satellite imagery, at minimum). A proper quote includes a design, expected production and a full price breakdown.
5. Compare quotes like for like
Use the same criteria across all quotes:
| Compare | Installer A | Installer B | Installer C |
|---|---|---|---|
| System size (kW) and panel count | |||
| Panel brand and exact model | |||
| Inverter type and model | |||
| Expected annual production (kWh) | |||
| Total price and price per watt | |||
| Financing terms and any fees | |||
| Warranties (equipment, workmanship, roof) | |||
| Timeline (permit to switch-on) | |||
| Who handles permits and interconnection |
Don’t choose on price per watt alone. See How to Compare Solar Quotes and Spot Red Flags for a deeper walkthrough.
6. Check references and past work
- Ask for at least two or three local references from installations that are a year or more old.
- Look at recent reviews and read the negative ones: how did the company respond?
- If possible, see an installation in person or ask for photos of finished roofs and wiring.
7. Read the contract carefully before signing
Make sure the contract states the exact equipment models, system size, price, payment schedule, warranties, timeline, who pulls permits, what happens if the design changes, and how the roof is protected. Get everything promised verbally in writing.
Questions to ask every installer
About the company
- How long have you been in business, and how many systems have you installed locally?
- Do you use your own employees or subcontractors for installation?
- What licenses, certifications and insurance do you hold? Can I see proof?
- Can you provide recent local references?
About the system
- How did you design this system, and how did you account for shading and orientation?
- What is the estimated annual production, and what assumptions does it use?
- Why did you choose these panels and this inverter? Can you quote an alternative? See Best Solar Panels for Homes and String vs Microinverters.
- Is the system battery-ready, and what would adding storage involve? See Do You Need a Solar Battery?
About warranties and service
- What warranties do I get on panels, inverter, and your workmanship, and for how long?
- If a panel or inverter fails, who pays for labor to remove and reinstall it?
- Who do I call if there’s a problem, and what is your typical response time?
- What happens to my warranty if your company closes? Is there a backing insurance or guarantee?
About money and paperwork
- What is the total cost, with all fees, permits, electrical upgrades and taxes included?
- What are the payment milestones and deposit requirements?
- If I’m financing, what is the interest rate, term and any dealer or origination fees baked into the price? See Solar Loans vs Cash vs Lease.
- Who handles permits, inspections and the utility application, and how long does it usually take?
- How do the savings estimate and payback work under my actual export rules? See Net Metering vs Export Tariffs.
Red flags: when to walk away
- High-pressure tactics: «this price is only good if you sign today» or artificial deadlines.
- «Free solar» claims or promises that you’ll pay nothing, forever. There is always a cost somewhere: a loan, a lease, a power purchase agreement, or incentives that may not apply to you.
- Vague references to «government programs» or claims that they represent your utility or the government.
- Guaranteed savings without a written, transparent calculation.
- No site visit and no roof or electrical inspection before quoting.
- Unwillingness to provide license, insurance or references.
- Very large upfront payment compared with the work completed.
- Quote much lower than all others with no explanation: cheap equipment, missing items or corner-cutting are common causes.
- Vague equipment descriptions («high-quality panels») instead of specific models.
- Door-to-door or cold-call sales pushing you to decide quickly. Take your time and get competing quotes.
- Financing hidden inside the quote: a low monthly payment can mask a high total cost or large dealer fees.
Know your rights
Consumer protections differ by country and state. In many places you have a cancellation period for contracts signed at home or off-premises, and solar sellers may be subject to specific licensing and disclosure rules. Check with your state or national consumer agency before signing, and don’t let anyone rush you past your cancellation window. In the UK, official guidance is available from GOV.UK and Citizens Advice; in the US, check your state attorney general or consumer protection office and the FTC.
After you choose: what a good installation process looks like
- Detailed design and permit applications handled by the installer.
- Equipment delivered matching the contract.
- Installation by qualified crews, with roof protected and work cleaned up.
- Inspection and grid approval before switching on.
- Commissioning and monitoring setup, with a walkthrough of how to read your app.
- Paperwork handed over: certificates, warranties, manuals and registration confirmations.
- Follow-up: check your system’s production against the estimate after a few months. See Solar Panel Maintenance Checklist.
Common mistakes when choosing an installer
- Choosing the cheapest quote without comparing what’s included.
- Focusing on panel brand and ignoring the installer’s track record.
- Signing after a single sales visit.
- Skipping credential checks.
- Not asking who services the system in the long run.
- Not reading the financing terms.
Next steps
- Prepare your bills and goals, then shortlist 3–5 installers.
- Verify each one’s credentials on official sites.
- Get itemized written quotes and compare them: Compare Solar Quotes and Spot Red Flags.
- Check references, read the contract, and only then sign.
Where to next:
Frequently asked questions
How do I choose a good solar installer?
Check their licenses, certifications and insurance, get at least three written quotes, read independent reviews, ask for local references, compare warranties, and avoid high-pressure sales. Choose on overall quality and trustworthiness, not only on price.
How many solar quotes should I get?
At least three, from different installers, each after a proper assessment of your roof and electricity use. Comparing them helps you spot unusually high or low prices and missing items.
What certifications should a solar installer have?
In the US, look for the appropriate state contractor license and, ideally, NABCEP-certified professionals. In the UK, look for MCS certification, which is required for export payments under the Smart Export Guarantee, plus membership of a consumer code such as RECC or HIES.
Is it better to use a local or a national installer?
Both can work. Local installers often offer faster service and a stronger community reputation, while national companies may offer scale and financing options. What matters is track record, references, warranty backing and who actually does the installation.
Are door-to-door solar salespeople trustworthy?
Some are, but this sales channel is associated with high-pressure tactics and misleading claims. Never sign on the spot. Get independent quotes and verify the company’s credentials first.
What happens if my solar installer goes out of business?
Equipment warranties from manufacturers usually remain, but workmanship warranties and service can disappear. In some countries, schemes offer insurance-backed guarantees. Ask about this before you sign, and keep all documentation.