TL;DR: Before signing a solar panel contract, ask your contractor about licensing, warranties, equipment brands, financing terms, and installation timelines. Choosing the wrong contractor can cost thousands—or leave you with a system that underperforms for decades. These 15 questions help you hire with confidence.
Going solar is one of the biggest home improvement investments you’ll make. The average residential solar system costs between $15,000 and $30,000 before incentives—and unlike a fresh coat of paint, a poorly installed solar system isn’t easy to undo.
The problem is that the solar industry has grown fast. Very fast. That rapid expansion has brought a wave of new contractors into the market, ranging from experienced professionals with decades of track records to companies that barely existed two years ago. Some are excellent. Others, not so much.
The difference between a great solar installation and a nightmare often comes down to one thing: the contractor you choose. A licensed, transparent, experienced contractor will walk you through every detail of the process. A cut-rate installer might disappear the moment you need warranty service.
Asking the right questions upfront protects your investment, your roof, and your peace of mind. Here are the most important solar panel contractor questions to ask before you put pen to paper.
Is Your Contractor Licensed, Bonded, and Insured?
Start here. Before discussing equipment or pricing, verify that your contractor holds the appropriate licenses for your state or region. Solar installation requirements vary by location, but most states require both a general contractor’s license and an electrical license.
Ask specifically:
- Are you licensed to perform solar and electrical work in this state?
- Are you bonded and insured? For how much?
- Can you provide proof of insurance before we proceed?
A reputable contractor will produce this documentation without hesitation. If there’s resistance or vague answers, walk away. Bonding protects you if the contractor fails to complete the job. Insurance protects you if a worker is injured on your property.
How Long Has Your Company Been Installing Solar Panels?
Experience matters. A company that has been installing solar panels for 10 years has dealt with edge cases, problem roofs, complex electrical systems, and post-installation issues that newer contractors simply haven’t encountered.
That doesn’t mean newer companies are automatically bad—but longevity is a signal of stability. If a contractor has been in business for less than three years, dig deeper. Ask how many systems they’ve installed, whether the leadership team has prior industry experience, and whether they have verifiable customer references.
What Certifications Do Your Installers Hold?
Licensing is the legal minimum. Certifications go further, demonstrating a commitment to professional standards.
The most widely recognized solar industry certification is the NABCEP (North American Board of Certified Energy Practitioners) PV Installation Professional certification. Installers who hold NABCEP certification have completed training, passed rigorous exams, and met documented experience requirements.
Ask your contractor:
- Do your installers hold NABCEP certification?
- How many certified installers will work on my project?
- Will a licensed electrician oversee the electrical work?
What Solar Equipment Brands Do You Use—and Why?
Not all solar panels are created equal. Top-tier manufacturers like LG, SunPower, Panasonic, and Q CELLS produce panels with higher efficiency ratings and longer performance warranties. Budget panels from lesser-known brands may seem appealing upfront but can degrade faster and perform worse over time.
The same applies to inverters. String inverters, microinverters, and power optimizers each have different cost profiles, efficiency characteristics, and failure rates. Ask your contractor to explain the equipment they’re recommending and why it’s the right fit for your home.
Ask specifically:
- What panel brand and model are you recommending?
- What is the efficiency rating of these panels?
- Which inverter technology are you using, and what are the trade-offs?
- Do you receive manufacturer incentives to recommend certain brands?
That last question is important. Some contractors push specific brands because of rebate arrangements—not because the equipment is best suited to your needs.
What Warranties Come With the System?
A residential solar system should last 25 to 30 years. Make sure you understand every warranty in the package before signing.
There are typically three distinct warranties to review:
Panel performance warranty: Guarantees that the panels will produce a minimum percentage of their rated output over time. Top manufacturers offer 25-year linear performance warranties, guaranteeing at least 80–90% output by year 25.
Panel product warranty: Covers defects in the physical panel. Standard product warranties range from 10 to 25 years depending on the manufacturer.
Workmanship warranty: Covers the quality of the installation itself—wiring, mounting, and roof penetrations. This comes from the contractor, not the manufacturer. Ask how long it lasts and what it specifically covers.
If a contractor offers a workmanship warranty of less than five years, treat that as a red flag.
Who Will Actually Install the System?
Many solar companies operate as sales organizations and subcontract the physical installation to third parties. This isn’t always a problem—but it does mean you need to know who’s going on your roof.
Ask your contractor directly:
- Will your company’s employees install the system, or will you subcontract?
- If subcontracted, who is the installation company?
- Are the subcontractors licensed and insured?
- Will someone from your company supervise the installation?
Knowing the answer protects you if something goes wrong and you need to identify who is responsible.
Can You Provide References From Recent Local Customers?
Ask for at least three customer references—and actually call them. Request contacts from jobs completed within the last 12 to 18 months, ideally in your area (since local contractors will be familiar with your utility company’s interconnection process).
When you speak with references, ask:
- Did the installation go smoothly?
- Was the system completed on time?
- How responsive has the contractor been to post-installation questions or issues?
- Would you hire them again?
Online reviews on Google, the Better Business Bureau, and platforms like EnergySage can supplement references—but personal referrals carry more weight.
What Does the Installation Timeline Look Like?
Solar installations don’t happen overnight. Between permits, inspections, equipment delivery, and utility interconnection, the average residential solar project takes two to four months from contract signing to grid connection.
Ask your contractor for a realistic timeline that includes:
- Permit application and approval
- Equipment lead time
- Scheduled installation date
- Utility interconnection and inspection
- Estimated first day of solar production
A contractor who promises an unusually fast timeline may be cutting corners—or may simply be overpromising to win your business.
How Will You Calculate My System Size?
A properly sized solar system is tailored to your actual energy consumption, roof orientation, shading conditions, and local climate. It should not be based on a generic formula or a contractor’s sales target.
Ask the contractor to walk you through their sizing methodology:
- Have you reviewed my electricity bills to assess my average consumption?
- Are you accounting for shading from trees or neighboring structures?
- What solar production software or modeling tool are you using?
- How many kilowatt-hours per year do you expect this system to produce?
Reputable contractors use tools like PVWatts (developed by the National Renewable Energy Laboratory) or Aurora Solar to model production estimates. If a contractor can’t explain how they arrived at their sizing recommendation, that’s a concern.
What Financing Options Are Available?
Most contractors offer multiple financing paths: cash purchase, solar loan, lease, or Power Purchase Agreement (PPA). Each has different cost structures, ownership implications, and impacts on your ability to claim federal tax credits.
Understand exactly what you’re signing:
- With a loan, you own the system and can claim the federal solar investment tax credit (ITC), currently set at 30% through 2032.
- With a lease or PPA, the financing company owns the system. You typically cannot claim the tax credit, and selling your home with a leased system can complicate the process.
Ask your contractor to clearly explain the total cost under each financing option, including interest rates, escalator clauses (annual payment increases in PPA agreements), and what happens at the end of the contract term.
What Happens If My Roof Needs Repairs After Installation?
Solar panels typically last 25 to 30 years. Your roof may not. If your roof needs replacing or repairs after installation, removing and reinstalling the panels can cost $1,500 to $6,000 or more depending on system size.
Before signing, ask:
- Is my roof in good enough condition to support solar panels for the next 25 years?
- If my roof needs repairs, can your company handle that, or will I need to find a separate roofer?
- What does panel removal and reinstallation cost?
Some solar contractors offer integrated roofing services or partnerships with roofing companies. If your roof is aging, addressing it before solar installation—rather than after—can save significant money.
What Are the Contract Terms and Cancellation Policy?
Read the contract carefully, and don’t let a sales representative rush you. Pay attention to:
- The exact equipment listed (model numbers, not just brand names)
- The total system cost and payment schedule
- The cancellation window and associated fees
- What happens if the contractor goes out of business before installation is complete
- Who handles permit fees and whether they’re included in the quoted price
A reputable contractor will give you adequate time to review the contract and consult with a trusted advisor before signing.
Making the Right Call Before You Commit
A solar installation done right will generate clean energy and meaningful savings for 25 years or more. One done poorly can mean roof leaks, underperforming panels, voided warranties, and a legal headache if the contractor disappears.
The questions above aren’t meant to intimidate contractors—they’re meant to filter for the ones who genuinely know their craft. An experienced, legitimate installer will welcome scrutiny. They’ll have clear answers, solid references, and documentation ready to share.
Take your time. Get at least three quotes. Compare not just price, but equipment, warranties, timeline, and the quality of the conversation. The contractor who answers these questions with confidence and transparency is the one worth trusting with your roof—and your energy future.
Frequently Asked Questions About Hiring a Solar Panel Contractor
What is the most important question to ask a solar panel contractor?
The most important question is whether the contractor is licensed, bonded, and insured in your state. This is the legal foundation of a legitimate installation. Without it, you have no protection if the work is substandard or a worker is injured on your property.
How do I verify that a solar contractor is licensed?
You can verify a solar panel contractor‘s license through your state’s contractor licensing board website. Many states have searchable online databases where you can confirm active license status, license type, and any disciplinary actions.
What is the NABCEP certification, and does my contractor need it?
NABCEP (North American Board of Certified Energy Practitioners) is the leading professional certification for solar installers. It’s not legally required, but it is a strong indicator that your installer has formal training and demonstrated competency. Prioritize contractors with at least one NABCEP-certified installer on their team.
Should I choose a cash purchase or a solar loan?
A cash purchase typically delivers the highest long-term savings and simplest ownership. A solar loan allows you to own the system—and claim the 30% federal tax credit—while spreading the cost over time. Leases and PPAs involve lower upfront costs but mean you won’t own the system or qualify for the tax credit.
How many quotes should I get before choosing a solar contractor?
Get at least three quotes from different installers. This gives you a realistic picture of fair market pricing, allows you to compare equipment recommendations, and helps you identify any outliers—either suspiciously cheap or unexpectedly expensive.
What should I do if a solar contractor refuses to provide references?
Walk away. A contractor who has successfully completed residential installations should have satisfied customers willing to speak on their behalf. Refusal to provide references is a significant red flag.