How Many Solar Panels Do I Need to Power My House?

You may be asking yourself, “How many solar panels do I need to power my house?” At Golden Group Solar our team approaches each solar panel installation project with a roofer’s eye.

The integrity of your roof and the structure under it is our top concern.

We highly recommend that if you are considering installing a solar roofing system for your home, you seek the guidance of a professional solar installer. Golden Group Solar will visit your home to examine your location, roof line and dimensions. Let us take the guesswork out of determining how many solar panels you will need to power your house. 

Solar panels on a residential roof.

Several factors affect the quantity of solar panels you will need. This number depends on:

  • The wattage per panel
  • Panel efficiency
  • The energy the solar panels will produce
  • Household energy consumption
  • Size of the panel
  • The number of peak sunlight hours available
  • The condition and shading of your roof
  • Your personal energy goals and needs

There is a formula you can use to determine how many you might need:

Desired energy production (kW) / Solar panel wattage (kW)
= Number of solar panels needed

You can use this formula to calculate how many solar panels you’ll need.  But first, you’ll need to know:

  • Your home’s monthly energy consumption
  • The wattage of the panels you plan to install
  • The amount of peak sunlight hours your home receives per day

Here are the steps you’ll need to take to work this formula successfully:

Step 1. Review your monthly electric bill.

Determine how many kilowatt-hours of electricity you use each month. Let’s use 1,500 kWh every month as an example.

Step 2. Convert monthly energy use to daily use.

Divide the monthly kWhs by the average numbers of days in a month to determine the daily average of electricity used. We’ll use 30.42 days (365 days divided by 12 months= average days in a month). This equals 49.3 kWh daily in our example.

Step 3. Then determine peak sunlight hours.

This number will depend on your location and climate. The National Renewable Energy Laboratory (NREL) provides sunlight information by state and for major cities. Let’s use 5 peak sunlight hours for our example. Divide the daily energy consumption by the number of peak sunlight hours to determine the amount of energy your solar panels need to produce each day. Energy production required = 49.3 kWh per day / 5 hours, which equals 9.86 kW.

Step 4. Lastly calculate the number of panels.

For this step, you’ll need to know the wattage of the solar panels you are going to install. (The average solar panel efficiency in the US is rated between 250 and 400 watts.) Let’s use a rating of 350 watts for our example. Now convert watts to kilowatts (kW) by diving 350 by 1,000. Hence, 350 watts = 0.35 kW.

Step 5. Finally, determine the required number of solar panels.

Divide the hourly energy production needed (9.86 kWh) by the solar panel’s power output. Number of solar panels needed = 9.86 kW / 0.35 kW per panel = 28.17 panels.

The homeowner in our example will need approximately 29 solar panels to generate enough electricity to match their current usage from the electric company. 

Remember, shading, roof orientation, and seasonal variations in peak sunlight are factors that can affect the output of your solar panels. Also, as families grow in age and size, their required electricity needs increase.

Is it a complicated process?

Yes, it can be. However, Golden Group Roofing & Solar is with you every step of the way. They will check the climate history in your area and get information from you so they can calculate the number of solar panels you’ll need. They will also recommend the ideal placement of the solar panels and give you options for features you may want to add to your system.

Contact us today for a solar installation quote.

At Golden Group, our team approaches each installation project with a roofer’s eye. The integrity of your roof and the structure under it is our top concern. We want you to benefit from solar energy, and we also want to make sure your roof can integrate the Solar PV System.

If you are considering a solar system for your home, our award-winning Golden Group team of professionals is committed to expertly installing high-quality solar roof panels for you. Contact Golden Group to start your solar energy journey today, harnessing the power of the sun for a more energy-efficient future.