How to Calculate Your Energy Usage for Going Solar

How to Calculate Your Energy Usage for Going Solar

There are plenty of advantages for building your own DIY solar system. Maybe you want energy independence, or to reduce your electric bills, or maybe you want to protect yourself from rising energy costs, maybe you'd like to make extra money doing "net metering", or maybe you just like the environmentally friendly aspects of solar power. Want it for your home, RV, off-grid cabin, remote site, or commercial space / workshop? Wherever you need it and whatever your motivation is, others have made their own DIY solar systems and so can you!

It's important to make a solar system plan, do some research, figure a ballpark project budget, shop around for good deals on solar panels and components, and start buying and building. When starting your solar system plan, you'll notice that one of the first questions that comes up is: "How much solar energy do I need to harvest from the sun?" This is very important to know because this will determine which solar panels you need to get and how many. We see this type of questions often, so here's a helpful guide to help you figure it out how to calculate your energy usage for going solar.

To calculate your energy usage, follow these steps:

  • Calculate your total kilowatt-hours (kWh) used each month. You can find this amount by gathering your electricity bills from the past year, they will tell you how many total kilowatt-hours (kWh) you used each month.
  • Calculate your average daily usage. Do this by dividing your total kWh usage for the year by 365 (number of days in a year).
  • Determine your peak usage period. Look at your electricity bills to see which month or months you typically use the most energy.
  • Determine the amount of energy you want to offset with solar panels.
  • Determine the size of the solar panel system you need. Divide your daily usage by the average number of sun hours in your area to determine the size of the solar panel system you need. You can find information on average sun hours in your area from a local solar panel installer or on online resources such as the National Renewable Energy Laboratory.
  • Consider other factors. Other factors to consider when purchasing solar panels include the efficiency of the panels, the cost, the warranty, and the installation process.

Now that you know how much solar energy you need and the size of the solar panels you need, it's time to start looking for solar panel deals. Here are a few solar panels we've used before that have worked for our builds.

Some solar systems merely help offset peak usage from the grid, but why not setup your solar system for off-grid use and for emergency energy storage? Since you now know the total kilowatt-hours (kWh) you use each month, you can start looking at ideas for building your own DIY solar battery, also known as a DIY Powerwall, to store extra energy for "net metering" or for emergency backup. There's lots of DIY Powerwall batteries and components available on

There's more to learn about building your own DIY solar system, but the rest will be for a future article. Learn more about this subject in this great book, DIY Solar Power. Keep on building!

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