It is usually a good idea to get more than one bid for installation of your solar system. Make sure that all the bids you receive are based on the same information and requirements. For example, comparing a bid for a system mounted on your roof with a bid for one mounted on the ground would not tell you how the two bids compare—it would probably tell you more about how the two types of installations compare.
One solution is to ask for bids on systems certified by the Solar Rating and Certification Corporation (SRCC). If possible, have each bid specify system type and size, energy output, maintenance requirements, and cost. Cost should include having the system installed and getting it up and running, as well as the cost of hardware, permits, sales tax, and warranties.
A system warranty is crucial in comparing bids. A solar rebate program may require a written installation warranty, for example a 2-year parts-and-labor warranty in addition to manufacturers’ warranties on system components. The company may offer other, longer warranties, particularly on the collectors. However, solar systems are more than collectors; active systems include electronic components, pumps, valves, and wiring. Make sure you know what your warranty covers and that the company stands behind the full warranty.
If you have several bids, you may wonder if the lowest bid is the best deal. Sometimes it is not. A solar thermal system installer is in business to make money; overhead and operating expenses must be covered. A low price could be a sign of inexperience, or of a company without staying power. Contractors that expect to stay in business must charge enough to cover their products and services plus make a fair profit. Price is not the only consideration.