How Many Solar Panels do I Need to Power My Home?

There are various reasons to invest in a home solar system, but many people find it difficult to decide how large a solar array they need. The truth is- almost any home solar kit is worth the investment. You don't need to be able to power your whole home with solar panels to make them worthwhile. Whether the system is 3kw or 13kw, it reduces a home's carbon footprint and saves money.

The first step in deciding how large a solar array is needed to power your home is to decide how much of your energy you want to produce with solar panels. While it would be great to achieve total energy independence, many budgets only allow for systems that power 25-50% of their energy usage. To see how much energy your home uses, pull out last month's energy bill. Energy consumption is measured in Kilowatt-hours (KWHs), and the number used each month is displayed on the bill. As this number varies by season, it is best to look at the yearly average of energy consumption when deciding how much power to produce.

Here is an example calculation. In 2014, the U.S. Energy Information Administration promulgated the average residential electricity consumption in Ohio to be 901 kWh per month. If the goal was to reach 75% energy independence, the target production rate would be 675.75 kWh per month. By dividing this number by 30.5, we can see that we want to produce 22.2 kWh every day.

Before we continue, a bit of information about solar panels. When you are looking at solar panels for sale, you'll see that panels are rated by size in Watts (W). Common home solar panels have 60 individual photovoltaic cells and range in size from 250-300W, with commercial 72 cell models extending that range up to 325W. A 255W solar panel is rated at 255W under very intense light conditions that rarely occur naturally. For this reason, panels are also given what is known as a Performance Test Conditions (PTC) rating, which more accurately predicts the solar panel's output. To show the importance of this rating, a Canadian Solar 255W solar panel has a 231W PTC rating. The solar kits we have assembled below display both the nominal output as well as show the expected PTC output.

So now we know that solar panels are measured in Watts- but how does that rating get translated into Kilowatt-hours? The metric-savvy person already know that a Kilowatt = 1000 Watts, but where do the hours come into play? A solar panel will produce its PTC rating for every hour of peak sunlight conditions. Find your location on this solar isolation map to see how many hours of peak sunlight conditions you can expect every day. These numbers are averaged over the course of the year to allow a more predictable average output. By dividing the daily goal of 22.2 kWh by 4.1, a common peak daylight hour reading for the Midwest, we can see that approximately 5.41 kWs worth of solar panels would be required to produce that target.

Based on this example, I would choose to purchase a 5.5 kW solar kit. Below are a list of common kit sizes and their prices, available for purchase from Edison Solar. Each home solar kit is comprised entirely of name brand, top-quality products such as Sharp 250W solar panels, Enphase M215 micro inverters, and UniRac mounting equipment. These systems are designed for longevity and ease of installation. While we always recommend using a certified solar installer for your solar array, these kits are as easy as they come for a DIY solar kit.

Edison Solar offers many name brand products in addition to Trina, including Canadian Solar, QCell, Suniva, SMA, Outback, Fronius, and others. If you would like to substitute these components for those of another brand, email us at contact@edisonsolar.net for alternate pricing that could save up to 20%.

Solar Kit SizePTC OutputPriceGovernment Tax RebateCost
3.025 kW2.7 kW$5500.00$1650.00$3850.00
5.5 kW4.9 kW$10,121.86$3,036.56$7,085.30
8 kW7.1 kW$15,078.94$4,523.68$10,555.26

Browse our full line of solar kits.