Residential solar is one of the larger home-improvement purchases a US household will make. The system is durable, but the experience of buying it varies enormously: some installers are careful local engineers; others are aggressive sales operations relying on financing markups. The difference often shows up only years later.
This guide walks through the practical signals that separate the two. It is written for homeowners getting their first quotes, and it focuses on questions you can ask before you sign anything.
What you are actually buying
A residential solar installation is a long-lived system — typically 25 years or more — composed of panels, an inverter, mounting hardware, and either a grid-tied or hybrid configuration with batteries. The quality of the work matters as much as the brand of the panels: penetrations through the roof, wiring runs, and conduit routing all affect both performance and the integrity of the building.
Treat the purchase like hiring a contractor, not buying a product. The installer is who you will be calling in year eight if something needs attention.
Credentials and references
Look for NABCEP certification on the company's installation staff (not just the company itself), proper state electrical and contractor licensing, and a record with the state attorney general or consumer protection office. The Better Business Bureau is a useful but imperfect signal; reading both five-star and one-star reviews is more informative than the headline rating.
Ask for two to three references from systems installed three or more years ago. New customers can only speak to the sales experience; older customers can speak to performance, service, and how the company handled problems.
How to read a solar proposal
A trustworthy proposal includes: panel make and model, inverter make and model, total DC system size in kilowatts, expected first-year production in kWh, a degradation assumption, total cash price, financing terms separately stated, and any dealer fees rolled into financed price.
Pay particular attention to dealer fees. Some solar lenders add 15–30% to the cash price as a hidden fee that lets the installer advertise a low interest rate. The cash price and the financed price should be in the same document, side by side.
- Is the cash price clearly stated, separate from financing?
- Are panel and inverter warranties listed by manufacturer?
- Is there a workmanship warranty from the installer, and for how many years?
- Who handles the interconnection paperwork with your utility?
- What happens if first-year production falls short of the estimate?
Watch for high-pressure tactics
Same-day discounts, 'this incentive expires tonight,' and quotes that are dramatically lower than competitors are not signals of a good deal. They are signals of a sales process that depends on you not getting other quotes. The federal solar tax credit and most state incentives do not change on 24-hour cycles.
Reputable installers expect you to compare quotes. If a company refuses to give you a written proposal without a same-day signature, walk away.
What the contract should say
At minimum, the contract should specify the system as designed, the total cash price, any financing terms, the installer's workmanship warranty, the manufacturers' product and performance warranties, and a production guarantee if one is offered. It should also name who is responsible for permitting and utility interconnection.
Have a friend or family member who has not been part of the sales conversation read the contract before you sign. Fresh eyes catch the clauses that get glossed over during a long pitch.