Mathematical Formula to Determine How Many Solar Panels You Need

Here’s the actual formula, used by EnergySage, that you can use you’re hoping to determine how many solar panels you’ll need:

Number of panels = system size / production ratio / panel wattage

Using the numbers we’ve determined so far, we get:

Number of panels = 11,000 kW / 1.6 / 300 W

That equates to about 20 to 25 solar panels to do the job. You can use this same formula to determine how many solar panels you’ll need to power your home. Or, you can use the easier route, which is to look at your energy bill to determine what you’ll need.

A Different Way to Figure Out Solar Usage

If you’re not interested in doing the math on your own, simply look at your utility bills to figure out how much energy you’re using. Doing this allows you to multiply your energy usage by the number of hours of strong sunlight your home gets, then dividing that result by the wattage of the panels you’re thinking of installing.