Best solar companies in Illinois: Our 2024 picks

High-quality installers care about their reputation. They want to install equipment that performs well and will last a long time. If you get quotes with equipment that you can't find much information about, that's a red flag. 

To get a sense of whether the equipment is trustworthy, first make sure it's included in EnergySage's solar panel, inverter, or battery equipment guide–and then see how we rate it relative to other equipment.

You can also check to see if the installer has any manufacturer endorsements, which attest to their expertise installing that brand's products. Most manufacturers require installers to go through a vetting process to ensure they're appropriately licensed and qualified before handing them an endorsement. The endorsements often come with perks that are passed onto customers, like preferred pricing or extended warranties. 

See our list of the best solar panels.

In the unlikely event there’s an issue with your solar panel system, it’s important to know who to call. Multiple warranties come with your solar panel system, including manufacturer warranties for the various equipment and your installer's workmanship warranty. 

The workmanship warranty covers all the labor your installer performs. It's typically somewhere between one and 10 years. But make sure to read the fine print because sometimes there are exclusions: You don't want to be stuck with a hefty bill if your installer needs to come out to check on or replace some equipment.

Solar is a growing industry that attracts contractors from many backgrounds—sometimes only loosely related to solar. But to feel confident in your solar panels, you'll want to work with an installer that has plenty of experience in custom designing systems. 

At EnergySage, we verify that all installers have at least two to three years of legitimate experience designing and installing solar panel systems before we let them join our Marketplace. We also confirm they have multiple successful installations under their belt.

Having the proper licenses and insurance policies is the bare minimum requirement for solar installers. But different states require different policies for solar installers. Sometimes even local jurisdictions have their own requirements. It can be difficult to keep track on your own, which is why we ensure our installers meet all qualifications in the areas they serve.

Certifications aren't necessarily required, but are a great way to weed out lower quality installers. The North American Board of Certified Energy Practitioners (NABCEP) offers an industry-leading certification program, while the PV Installation Professional (PVIP) Board Certification is the gold standard for solar installers.

Certification isn't a firm requirement for EnergySage installers, but it's highly recommended. If the installer started working in the solar industry before NABCEP was formed in 2002 and has a long (and positive) track record, we may still allow them to join our Marketplace.

Some solar companies rely on subcontractors to perform some–or all–the work during your solar installation. Don’t let this put you off: It’s entirely standard procedure in the industry. 

What is alarming, though, is a lack of transparency from installers about who will install your system and why they use subcontractors.

When you’ve narrowed down your list of potential solar installers, be sure to ask who will install the system: their own crew, or subcontractors. If they use subs, ask why, what portion of the install the subcontractors will complete, and what oversight the company you purchase your system from has over the subcontractors. 

At the end of the day, the most important question is who will stand behind the quality of your installation.

The fastest way to evaluate an installer's reputation is to look through reviews from actual customers. How many five-star ratings do they have? Are there complaints about responsiveness? EnergySage, Google, Reviews.io, Reddit, and Yelp can all be good places to look for reviews.

Just keep in mind that reviews don't always paint the complete picture. They often focus on extreme ends of the customer experience, whether that's good or bad.

Check out some user reviews from verified EnergySage customers: