How do I choose among competing bids on solar panel installs?

Have you decided to get more than 1 bid on the installation of your solar electric system? (it's a good idea to do so), you now need to take the steps to ensure that all of the quotes you receive are made on the same rate basis. As an example, comparing a quote for a system mounted on the ground against another quote for a rooftop system is not going to be the same price or equipment. Due to different types of solar electric panels generate more electricity per square foot than others can do so this out weights a lot of things.

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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).

Its clear top see the amount of energy depends on the amount of sunlight you have at any due time - which varies by location, season, and year to year - their is no one specific figure.

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What about high quotes?

At range of + 20% is more realistic. Quotes should include the total costs of setting the solar electric system up and getting it running, including all hardware, plus the installation, connection to the grid, permitting, sales tax, and your warranty. The warranty is a very important factor for evaluating quotes. As all solar rebates may require that systems be covered by, a 2 year parts-and-labor written installation warranty, in addition to any manufacturers' warranties on all specific components. The installer may offer longer warranties. Also ask yourself, "Will this company stand behind the full-system warranty for the next 2 years?"