Size Your PV System

What Size Solar Panel System Do I Need?

Size a solar panel array for your home with our easy solar system calculator. Just fill out the form and click "Size My Solar System"!

1. How many KiloWatt-Hours (kWh) do you use per month? (Look at your electric bill) kWh
2. What percentage of this power do you want to offset with solar? %  
3. Which state do you live in? (Determines hours of daily sun you receive)
Minimum PV System Size
Recommended PV System Size





More Information on Sizing Your Solar PV System

“How much will it cost to power my XX,XXX square foot house?”
“How many solar panels do I need to eliminate my electric bill?”

We get questions like this every day from homeowners in the beginning stages of going solar.

It’s all going to depend on the load. 

To begin, calculate your average energy usage in kWh. Collect your electric bills for the past 12 months or more.

kWh Electric Bill

Get an average of kWh used on a monthly basis. Let’s say that this number is 1100 kWh per month.

Now divide your average monthly usage by 30 to get your average daily kWh usage. In this case, it would be about 37kWh per day.

To keep things simple for this rough estimate, we’ll assume that a 250W solar panel will produce about 1kWh a day. **Keep in mind that this is a rough estimate, based on a site location getting 4 hours of sunlight per day**

Assuming that you use about 37 kWh per day, you would need about 37 solar panels to meet 100% of your average energy needs.

Based on your current usage, how much of this do you want to offset with a solar power system?

100% …75%…. 50% ? Multiply accordingly.

Let’s say you wanted your solar system to account for 80% of your energy consumption.

37 kWh per day x 0.80 = 29.6 kWh

Since one solar panel produces about 1 kWh per day, you would use 30 solar panels to account for 80% of your average consumption.

The purpose of this is to give a rough idea of how many solar panels you will need. This sizing tool provides a quick number to go off of as you’re shopping around- it’s not a replacement for having an electrical contractor design a system for you.

Once you’ve calculated your average kWh use and determined the percentage that you plan to offset with solar, get a free solar quote from We’ll help you design a complete system that’s specific to your roof and geographical location.


DIY Micro Inverter Solar Kit

Our easy DIY Micro Inverter Solar Power Kits range from 2kW - 7kW, and come complete with solar panels, micro inverters, racking, and attachments. Learn more here »


DIY String Inverter Solar Kit

Our cost-effective DIY String Inverter Solar Power Kits range from 3kW - 8kW, and come complete with solar panels, string inverter, racking, and attachments. Learn more here »

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Solar is one of the best investments you can make - act now before the 30% tax credit expires in 2016!

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