Whether you’re getting ready to build, or want to know if solar power can work for you, here are three factors you’ll want to consider:

1. How much full sunlight per day do you get? Experts call this the “insolation” factor. You can find out what the approximate insolation factor is for your site on a solar map created by the National Renewable Energy Laboratory. You’ll also need to know some additional site-specific factors like sun blockage by trees, other buildings, hillside, or any other obstruction.

2. Current electricity prices. To determine your payback time, knowing what you’re currently paying (or the average cost for homeowners in that area per watt for electricity) can help you determine how long it will take you to pay for solar power installation. Unless you plan to build the solar system yourself, a big part of this equation is the length of time you plan to stay in this home. The longer you’re in the house, the bigger the payback.

3. What rebates and tax incentives are available? Maximizing federal and state incentives can help offset the initial cost of installing a solar power system. If you have a solar system installed professionally, you may be looking at $40 to 60 thousand dollars for the average American home.

Let’s face it. If you live in an area or on a site that doesn’t get enough direct sunlight to generate much of a solar power system, it simply may not be worthwhile no matter how much you want to do it.