The company should have their state contractor’s license from the state in which they work. Make sure that the company is covered in case of any emergencies. You don’t want to be held liable if their workers hurt themselves on your property.
It would also be helpful to find a company that is certified by the North American Board of Certified Energy Practitioners (NABCEP). When a company works to get certified by these trade organizations, they’re showing their customers that they are willing to go the extra mile to provide the best service possible as described on RepairDaily blog.
Many companies have a particular manufacturer that provides them with the equipment that they need. Ask the company which manufacturer they work with. Make sure that the ones they work with provide quality parts for their solar panels and inverters. For example, GE Energy and SMA America are 2 manufacturers that are known for their quality parts. If it’s a manufacturer that you’re unfamiliar with, don’t hesitate to do some research into them before making your final decision.
Some companies will use their contractors to perform the labor on your home. Other companies will use sub-contractors. Make sure that you know who will be working on your home. If the company uses sub-contractors, ask about their service. Do some research into the sub-contractors, too.
One of the best ways to compare companies is by getting bids from each one. When getting bids, make sure that each company includes everything from engineering the parts to building permits for your home. Find out if the company will help you file rebates and complete metering paperwork. As you compare the bids, you should have all the information that is available to you.