Making the switch to solar energy is one of the smartest upgrades you can make for your home. It promises lower electricity bills, a smaller carbon footprint, and increased property value. However, the gap between a high-performing solar system and a rooftop nightmare often comes down to one factor: the contractor you hire.
The solar industry has exploded in recent years. While this growth has made technology more accessible and affordable, it has also attracted a flood of new companies. Some are experienced professionals committed to quality, while others are aggressive sales operations looking to make a quick profit before moving on to the next boom.
Separating the experts from the amateurs requires more than just a quick Google search. You are planning a major construction project on your roof that involves high-voltage electricity and complex integration with your local utility grid. This isn’t the time to cut corners.
Before you sign any contracts or put down a deposit, you need to conduct a thorough interview. To help you navigate this process, we have compiled the twelve essential questions you must ask every prospective solar installer. Their answers will tell you everything you need to know about their reliability, expertise, and long-term viability.
1. Are you licensed and insured to work in my state?
This might seem basic, but it is the single most important question to start with. Solar installations require specific electrical and construction licenses that vary by state and municipality. A general solar panel contractor‘s license is often not enough; many jurisdictions require a specific solar classification or an electrician’s license.
Why this matters:
If an unlicensed contractor works on your home, you are exposing yourself to significant liability. If a worker is injured on your property and the company doesn’t have workers’ compensation insurance, you could be sued for their medical bills. Furthermore, if the system is installed incorrectly and causes a fire or roof leak, your homeowner’s insurance may deny the claim if the work wasn’t performed by a licensed professional.
The answer you want:
The contractor should readily provide their license number and proof of general liability and workers’ compensation insurance. Do not just take their word for it—verify the license number with your state’s contractor board online.
2. How many years have you been installing solar systems?
The solar “solar coaster” is a real phenomenon. Companies spring up when incentives are high and vanish when policies change. You want a partner who has weathered a few storms and stuck around.
Why this matters:
Experience translates to accurate system sizing, cleaner conduit runs, and fewer holes in your roof. A company that has been in business for five or ten years has likely streamlined its installation process and ironed out common mistakes. A brand-new company might be learning on the job—with your house as the classroom.
The answer you want:
Look for a company with at least three to five years of operating history specifically in solar. If they are a roofing company that just added solar last month, proceed with caution. You want a specialist, or at least a company with a dedicated, experienced solar division.
3. Who will be performing the actual installation?
Many solar companies are actually just sales organizations. They market the systems, sign the contracts, and then subcontract the actual labor to a third party. While subcontracting isn’t inherently bad, it adds a layer of complexity to the project.
Why this matters:
When subcontractors are involved, accountability can get lost. If the crew doesn’t show up on time, or if they leave a mess in your yard, the person who sold you the system might not have the authority to fix it immediately. Furthermore, subcontracted crews are often paid by the job (or even by the panel), which can incentivize speed over precision. In-house crews are typically hourly employees who are trained to meet the company’s specific quality standards.
The answer you want:
Ideally, you want a company that uses its own in-house employees (W2 workers) for the installation. If they do use subcontractors, ask how long they have worked with that specific crew and what quality control measures are in place.
4. What specific warranties do you offer?
Solar warranties can be confusing because there are usually three different types covering one system. You need to understand the difference to know how well you are protected.
The three types of warranties:
- Equipment Warranty: This comes from the manufacturer (e.g., LG, Panasonic, Q Cells) and covers defects in the hardware itself.
- Performance Warranty: Also from the manufacturer, this guarantees that the panels will produce a certain percentage of their original power output after 25 years (usually around 85-92%).
- Workmanship Warranty: This comes from the contractor and covers the labor and installation quality. If a wire comes loose or a roof penetration leaks, this is the warranty that saves you.
Why this matters:
A 25-year equipment warranty is useless if the company that installed it offers only a 1-year workmanship warranty and then goes out of business.
The answer you want:
Look for a workmanship warranty of at least 10 years, though 25 years is becoming the industry gold standard. Be sure to ask who services the labor warranty if the contractor retires or closes up shop.
5. Can you provide local references from the past year?
Reviews on Google and Yelp are helpful, but they can be faked or incentivized. Speaking directly to a past customer gives you unfiltered insight into the contractor’s communication style and reliability.
Why this matters:
Solar installations are rarely one-day events. They involve permitting, inspections, and utility interconnection, a process that can take weeks or months. You need to know if the contractor keeps customers updated during the “quiet periods” when paperwork is being processed.
The answer you want:
Ask for the names and numbers of three clients in your area who had systems installed in the last 12 months. When you call them, ask: “Did they finish on time?”, “Was the final price exactly what they quoted?”, and “Did they clean up after themselves?”
6. How do you determine the system size I need?
If a contractor glances at your roof on Google Maps and immediately quotes you a system size, run the other way. Proper sizing requires data.
Why this matters:
An undersized system won’t offset your bill enough to yield a good return on investment. An oversized system is a waste of money because most utilities will not pay you full retail rates for the excess power you produce.
The answer you want:
A professional contractor will ask for your last 12 months of electricity bills to analyze your kilowatt-hour (kWh) usage. They should also ask about your future plans. Are you buying an electric vehicle? Installing a pool pump? Planning to retire and spend more time at home? A good proposal is customized to your specific consumption habits, not just your roof square footage.
7. What equipment (panels and inverters) do you recommend and why?
Not all solar panels are created equal. There are “Tier 1” premium panels and cheaper economy options. Similarly, the choice between string inverters, microinverters, and power optimizers will affect your system’s efficiency and cost.
Why this matters:
If you have a roof with significant shade from trees or chimneys, a standard string inverter system will perform poorly because shade on one panel will drag down the performance of the whole string. In this case, you would need microinverters or optimizers.
The answer you want:
The contractor should be able to explain why they chose a specific hardware setup for your home. They should not just push whatever brand they have in stock. Ask them to explain the pros and cons of the inverter system they are proposing.
8. How does the financing work?
There are three main ways to pay for solar: cash, loan, or lease/Power Purchase Agreement (PPA). Each has vastly different financial implications.
Why this matters:
- Cash/Loan: You own the system. You get the federal tax credit (ITC) and any local incentives. This usually offers the best long-term savings.
- Lease/PPA: The solar company owns the system. You pay them a monthly fee for the equipment or the power. You generally do not get the tax credit, and selling your home can become complicated because the new buyer has to qualify to take over the lease.
The answer you want:
Be wary of contractors who aggressively push a lease or PPA without explaining the ownership benefits of buying. They should be transparent about the interest rates, dealer fees, and total cost of ownership for each option.
9. Who handles the permitting and utility interconnection?
Installing the panels is the easy part. The bureaucracy is the hard part.
Why this matters:
Your local building department requires permits. Your Homeowners Association (HOA) might require architectural approval. Your utility company requires an interconnection agreement to allow you to send power back to the grid. If these aren’t handled correctly, you could end up with a beautiful solar system on your roof that you aren’t legally allowed to turn on.
The answer you want:
The contractor should handle 100% of the paperwork. They should know the specific requirements of your local jurisdiction and utility. If they ask you to pull your own permits, treat that as a major red flag.
10. Will you inspect my roof before installation?
Solar panels have a lifespan of 25 to 30 years. Your roof needs to last just as long.
Why this matters:
If you install solar panels on a roof that only has five years of life left, you are setting yourself up for a costly headache. When the roof eventually needs replacing, you will have to pay a solar crew to remove the panels, store them, and reinstall them after the roofers are done. This can cost thousands of dollars.
The answer you want:
A reputable installer will inspect the condition of your shingles or underlayment. If your roof is nearing the end of its life, they should be honest and recommend you replace the roof before installing solar. Many companies even coordinate with roofers to do both jobs simultaneously.
11. What happens if my roof leaks after installation?
Penetrating a roof to attach racking equipment always carries a slight risk of water intrusion. You need to know who is responsible if the ceiling starts dripping during the next rainstorm.
Why this matters:
Roof leaks can cause thousands of dollars in structural and cosmetic damage. You need clear language in your contract regarding penetration warranties.
The answer you want:
The contractor should have a specific warranty covering roof penetrations. This is often part of the workmanship warranty, but it is worth clarifying. Ask specifically: “If a leak is traced back to a solar mount, will you pay for the interior repairs to my home, or just the roof repair?”
12. How will I monitor my system’s production?
Once the system is live, you need to know it is working. You shouldn’t have to wait for your electricity bill to arrive to realize your system has been offline for three weeks.
Why this matters:
Solar systems are generally reliable, but inverters can fail and breakers can trip. Without monitoring, you are flying blind.
The answer you want:
Most modern systems come with app-based monitoring (e.g., Enphase Enlighten, SolarEdge). The contractor should set this up for you and teach you how to read it. Ask if they also monitor the system remotely. Some premium installers receive alerts if your system goes down and will contact you proactively to schedule a repair.
The Bottom Line
A solar panel system is a 25-year relationship. You aren’t just buying a product; you are hiring a partner. While price is important, the cheapest quote is often the most expensive in the long run if it comes with poor installation, cheap equipment, or a company that ghosts you when problems arise.
Take your time with these questions. A high-quality contractor will appreciate your diligence because it gives them a chance to demonstrate their expertise. If a salesperson gets annoyed, evades your questions, or pressures you to sign today for a “special discount,” take that as your cue to walk away. The sun isn’t going anywhere, and neither should your peace of mind.