The number of solar panels it takes to power a house varies by the amount of power the household uses, and the amount of power the panels provide. Other factors you’ll need to consider are the size of your roof, how much sun your roof gets, and the output in watts of the panels you are going to use.
How to find out how much power your home uses
The amount of power you are using can be found on your utility bill. It lists your electrical consumption by month. Add up how much power you used all year and divide that by 12. Unless you are planning for upgrades such as an EV charger or pool pump, that sum is the amount of power you want your system to generate. Some utility companies allow you to have the system produce more than you use. San Diego Gas and Electric, for example, allows you to generate about 115% of your normal usage.
Project Sunroof – How to figure out how much sun your roof gets
Google provides a free online tool called Project Sunroof that will determine how much sun your roof gets and estimate your savings from going solar. It’s easy to use. Simply enter your home address and it will find your home and show you how much sun your roof gets and how much room it has for solar panels. You can then enter the amount of power you get billed for and Project Sunroof will estimate how many kilowatts your system needs to produce to cover your electrical usage.
Last step: Find out how many solar panels you’ll need
Now that you know the size of the solar power system you’ll need, you can figure out how many solar panels you’ll need. Solar panels vary by power output, so you’ll need to decide which panels you’re going to use. For example, Freedom Forever has solar panels that vary in wattage from 285 to 360 watts. If your home needs what the average home in California uses, which is 6 kW, then divide 6,000 by the wattage of the panel you’re going to use. With 285 watt panels, it would take 21 panels to provide 6 kW. With 360 watt panels, it would take 17 panels to provide 6 kW.