To calculate the number of solar panels your home needs, divide your home's annual energy usage, which is measured in kilowatt-hours (kWh), by your local production ratio. Then take that number and divide by the wattage of the solar panels you're considering. . Most homes need 15-22 solar panels to ditch their electric bill. Here's how to figure out your magic number. Why trust EnergySage? As subject matter experts, we provide only objective information. We design every article to provide you with deeply-researched, factual, useful information so that you. . Estimates the energy production of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations. Operated by the Alliance for Sustainable. . Most homeowners need between 15-25 solar panels to power their entire home, but this number varies significantly based on your energy usage, location, and roof characteristics. If you're consuming 1,000 kWh per month in a sunny state like California, you might need just 16 panels, while the same. . Once you've determined the right kind of solar panels for your home, look at your latest electric bill. Next, you'll need to determine the necessary solar panel. .