A Step-by-Step Guide to Calculate Your Solar Energy

At SunWatts, we make solar simple, and calculating how much solar you need has never been easier. On our Calculate How Much Solar page, you will learn how much solar power in kilo-watts or kW is needed to generate the kilo-watt hours or kWh of energy used at your property.

To find the calculator, go to “Get Started” from the main menu along the top of the screen for a computer or tablet, Or tap the menu icon at the top left on a mobile device. Hover over “Get Started,” then click “Calculate How Much Solar” to see the Solar Calculator. To estimate your solar system size, you will need three pieces of information to calculate the solar kilo-watts.

1. Your utility power bill for the last 12 months
2. The solar hours per day for your location
3. The percentage amount of the power bill you want to be covered

Now, let’s look at each item in more detail.

Your power bill. Having a year’s worth of monthly power bills would be best. On each power bill, locate each month’s kilo-watt hours or kWh. That is how much energy you consume. Some power bills have a summary chart; you might find your kWh there. The summary chart may show the average daily kWh used for the past 12 months. If so, you can enter the total kWh for the year. If no total is provided, add the kilo-wat hours for each month and enter the total into #1 on our Solar Power Calculator. Do NOT include commas or decimal points. For example, the average home in the USA uses 30 kWh daily. Multiply that by 365 days, and the average home in the USA uses 11,000 kWh of electricity per year. (30 x 365 = 11,000) So let’s enter 11000 into field #1.

The next information to look at is the solar hours per day for your location. The average solar hours per day in the USA is between 4-6 hours. The AVERAGE solar hours per day. It’s longer in the summer and shorter in winter. Now, scroll down the page to find your state and nearest city for the solar hours. For our example, let’s use the first location on the list. Birmingham, Alabama, has 5.26 solar hours per day.

Enter this number into #2, Solar Hours per Day.

The final piece of information is the amount of your electricity bill you want to cover. 50%, 80%, 100%, 120%. It’s up to you. But let’s start with 100%. Enter the whole number into #3, Do NOT include the percent symbol (%).

For our example, you should enter:

1. 11000
2. 5.26
3. 100

You’re ready to click calculate! The example answer should be 7.64.

Let’s take a closer look at the final result after you clicked calculate:

This means that 7.64 kW or 7,640 watts of solar should generate 11,000 kilo-watt hours per year in Birmingham, Alabama. You now know how to calculate the kW size you need for a solar kit that will generate the kWh you need. To find the price and more details for a solar kit, view Solar Kit Sizes, or use the menu by choosing Solar Kit, then Solar Kit Sizes. You will see that we have many different size solar kits, from 1,000 to 1 million watts.

Watch our full tutorial video to Calculate How Much Solar Your Need. 

SunWatts. Solar Made Simple.