Selecting a PV provider

Who sells and installs ?

In some locations, finding a PV provider can be as simple as picking up the telephone directory and looking under “Solar Energy Equipment and Systems—Dealers.” Be aware, however, that many of those listings are for solar water-heating companies. Many of these companies may not be experienced in PV system design or installation. Similarly, many electrical contractors, although proficient in typical electrical contracting work, may not have expertise in PV or with residential roofmounting techniques. How do you identify solar electric system providers? Here are several suggestions.

  • Check the Directory of the U.S. Photovoltaics Industry
  • Contact the for a list of solar service providers (202-383-2600).
  • Contact your utility company to see which vendors it might recommend.
  • Conduct a search on the Internet. Unless you are skilled in PV installation, you should consider hiring a reputable professional contractor with experience in installing PV systems.

How do I choose among PV providers?

Compile a list of prospective PV providers. You might first consider those closest to you, because the contractor's travel costs might add to your system price. Next, contact these providers and find out what products and services they offer. The following questions may give you a good sense of their capabilities:

Has the company installed grid-connected PV systems? If not, has it installed gridindependent PV systems?

Experience installing grid-connected systems is valuable because some elements of the installation—particularly interconnection with the local utility—are unique to these systems. Because grid-connected systems are relatively uncommon, most contractors with PV experience have worked only on systems such as those that power remote cabins far from the nearest utility line. This means they have experience with all aspects of PV system installation except the connection with the utility grid. Although grid-connection work is different from “off-grid” work, a competent company with PV experience should not be eliminated just because it has not installed grid-connected PV systems in the past. In fact, experience with off-grid systems is valuable because grid-independent systems are more technically complicated than grid-tied systems.

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 an ability to work with customers and to compete effectively with other firms.

Is the company properly licensed?

PV systems should be installed by an appropriately licensed contractor. This usually means that either the installer or a subcontractor has an electrical contractor's license. Your State Electrical Board can tell you if a contractor has a valid electrician's license. Local building departments also may require that the installer have a general contractor's license. Consumers should call the city and county in which they live for additional information on licensing.

A solar rebate program may require that, in addition to being properly licensed, installers must demonstrate that they possess special knowledge about installing PV systems. This special knowledge may be demonstrated in one of the following ways:

  • Possession of a solar contractor specialty license, issued by a local building jurisdiction, that recognizes—through testing or other means—special knowledge of PV systems.
  • Certification in PV systems by a group such as the Arizona chapter of the Solar Energy Industries Association.
  • A letter from the manufacturer of the PV system stating that the installer has experience and/or training necessary to install the system properly.

Does the company have any pending or active judgements or liens against it?

As with any project that requires a contractor, due diligence is recommended. The Arizona Registrar of Contractors can tell you about any judgments or complaints against a statelicensed electrician. Consumers should call the city and county in which they live for additional information on how to check up on contractors. The Better Business Bureau is another source of information on contractors.

How do I choose among competing bids?

If you have decided to get more than one bid for the installation of your PV system (and it's generally a good idea to do so), you should take steps to ensure that all of the bids you receive are made on the same basis. For example, comparing a bid for a system mounted on the ground against another bid for a rooftop system is like comparing apples to oranges. Similarly, different types of PV modules generate more electricity per square foot than others. Bids should clearly state the maximum generating capacity of the system (measured in watts or kilowatts). If possible, have the bids specify the system capacity in “AC watts” under a standard set of test conditions, or specify the output of the system at the inverter.

You may want to obtain some estimate of the amount of energy that 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 by location, season, and year to year—it is unrealistic to expect a specific figure. A range of ±20% 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.

Your warranty is a very important factor for evaluating bids. A solar rebate program may require that systems be covered by, say, a twoyear parts-and-labor written installation warranty, in addition to any manufacturers' warranties on specific components. The installer may offer longer warranties. Also ask yourself, “Will this company stand behind the fullsystem warranty for the next two years?”

Is the lowest  price the “best deal”?

It might not be. Often, you get what you pay for. Remember that a PV company is a business just like any other, with overhead and operating expenses that must be covered. It's always possible that a low price could be a sign of inexperience. Companies that plan to stay in business must charge enough for their products and services to cover their costs, plus a fair profit margin. Therefore, price should not be your only consideration.