How to Calculate Solar Power for a Home

Calculating the energy required to power your place of residence is the first step to creating a solar-powered home.

Solar panels provide you with a sustainable and, in the longterm, inexpensive alternative to conventional energy solutions. Before you invest in solar panels, however, you must determine how many solar panels you will need to fulfill your home's energy needs. With a simple equation and a solar insolation map, you can not only determine the energy needs of your home, but you can also ensure that these needs are met even during the times of the year when your home receives the least amount of sunlight.

Things You'll Need

• Electric bills from the last 12 months
• Calculator
• Pencil
• Paper

Instructions

1. Add together the total number of kilowatt hours (kWh) your home has used each month for the last twelve months.

2. Divide the answer by twelve to determine the average monthly kWh usage.

3. Divide the average monthly kWh usage by 30 to determine the average daily kWh usage.

4. Refer to the solar insolation map in the "Resources" section of this article to determine the amount of solar energy hours received each day at your location.

5. Divide the average monthly kWh usage by the amount of solar energy hours you receive each day. Multiply this value by the constant 1.25 to account for energy lost through wiring, batteries, and power inverters. The new value is the amount of energy in kWh your solar panels will need to provide.

References

• DIY Solar Homes: 3 Steps to Calculate Home Solar Power Needs

Resources

• altE University: Solar Insolation Map