Choosing a Solar Professional
California is home to a number of reputable solar professionals with experience installing Solar Electric and Solar Thermal systems. Finding an electrical, HVAC or roofing contractor can be as simple as picking up the telephone directory. But when choosing a contractor for a solar electric or solar thermal project, many contractors may be highly proficient in their trade, but might not have expertise in designing and installing a Solar Photovoltaic (PV) or Solar Thermal system. A good place to start your search for a local solar energy professional is right here. However, remember that it’s up to you to carefully select whom you hire.
How do I choose among solar contractors?
Whether you use our directory of local solar professionals or compile one of your own, the next step is to narrow it down by interviewing solar contractors and asking questions. When selecting a company, consider its location relative to yours. If you can locate a solar contractor who is relatively close to where the system will be installed and who meets the other criteria outlined below, it’ll be easier to work with them rather than with a company located farther away. When evaluating a solar professionals experience and expertise, you might ask some of the following:
What kind of solar experience does the contractor have?
Because installing solar energy systems requires a range of expertise, you should ask how many installations the contractor has completed for your particular type of system. If you’re interested in a grid-connected system, try to find a contractor who has performed interconnections with your local utility. Although grid-connected systems are different from remote systems, a competent contractor with PV experience should not be eliminated just because they haven’t installed grid-connected PV systems in the past. In fact, previous experience with remote systems is valuable because utility independent systems can be more technically complicated than grid-connected systems. The bottom line, however, is that a competent contractor will be able to work on both on-grid and off-grid systems in a professional manner. In addition, many contractors got their start doing solar water heating system installations. Although quite different from PV systems, they both require expertise in roof attachment and solar resource assessment. Experienced solar water heating contractors know how to mount arrays without causing leaks in your roof and how to make maximum use of the sun for your particular site.
How many years of experience does the company have installing PV systems?
This issue speaks for itself: A company or contractor that has been in business a long time has demonstrated the ability to work with customers and to compete effectively with other firms.
Is the company properly licensed/certified?
First of all, make sure the contractor is properly licensed and bonded with the state Contractor’s Licensing Board.
In California, the California Contractors State License Board administers contractor licenses. The C-46 Solar Contractor license covers active solar water and space heating systems, solar pool heating systems, and photovoltaic systems. C-46 requirements include four years of experience and passing the business and law exam and the trade exam.
Other contractor licenses for solar include:
A. General Engineering
B. General Building
C-4. Boiler, Hot Water Heating and Steam Fitting (for solar thermal systems)
C-10. Electrical (for photovoltaics only)
C-20. Warm-Air, HVAC (HVAC systems that utilize solar energy)
C-36. Plumbing (solar thermal systems)
C-53. Swimming Pool (for solar pool heating).
How do I obtain and choose among competing bids?
It is always best to get more than one bid for the installation of your solar energy system, and you should take steps to ensure that all of the bids you receive are made on the same criteria. As an example, comparing a bid for a system that would be mounted on the ground versus another bid where the system would be mounted on a roof would be like comparing apples with oranges. Similarly, there are different types of solar collector panels, some of which generate more electricity per square foot than others. Bids should clearly state the peak generating capacity of the system under full sunlight (measured in watts or kilowatts). Also, you should obtain an estimate of the amount of energy the system will produce on an annual basis (measured in kilowatt-hours). Because the amount of energy depends on the amount of sunlight, which varies from season to season and year to year as well as geographically, it’s unrealistic to expect a specific figure; a range of ±20 percent is more realistic. Bids also should include the total cost of getting the PV system up and running, including hardware, installation, connection to the grid, permitting, sales tax and warranty.
System warranty. A good standard to use when considering the length and terms of PV system warranties is two years for labor, five years on the power electronics and 20+ years on the solar modules. When the system is professionally installed rather than self-installed, the warranty also should include the labor of removing and reinstalling any defective components, and shipping costs.
Check references. As with hiring any contractor, be sure to call several references provided by the contractor. Ask previous customers if they would hire the contractor again, what they would have done differently, and to describe the contractor’s limitations and strengths.
Is the lowest price the best deal?
It might not be. Ultimately, you, the purchaser, must decide how much you wish to pay for your PV system. However, remember that a solar contractor is a contracting business just like any other type of contractor, with overhead and other operating expenses that must be covered. Companies that plan to stay in business must charge a price for their products and services that is adequate to cover their costs plus a fair profit margin. If you let price be your only consideration, you ultimately might wish that you had based your purchase decision on other factors as well.
Verifying and accepting the installation
If you’re hiring a professional to do the installation, ask them to verify that it delivers what they said it would. To do this, you’ll have to take a power reading on a sunny day when there is no cloud cover. The system should deliver what the contractor claimed it would when the sun is striking perpendicular to the collector. If the sun is striking at an angle less than perpendicular to the collector surface, then performance must be derated by the cosine of the angle between the sunlight and the perpendicular to the collector surface. Before accepting the completed installation, make sure you understand the controls and any maintenance requirements it has.
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