Going Solar: A Step-By-Step Guide To Calculate How Many Panels You Need

Team Solarblocks Energy
December 14, 2023
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Going Solar: A Step-By-Step Guide To Calculate How Many Panels You Need

Inflation, high energy prices, and electricity bills have made the idea of a solar-powered home popular among the masses. But as people start considering the benefits of installing residential solar panels, a common question remains — how many solar panels do I need? 

Well, to answer this, it depends on multiple factors. 

Knowing the accurate number of solar panels required for your home is subject to factors like the roof size, surface area, orientation, the location of the property, etc. In this blog, our experts will help you calculate the number of solar panels needed to power a home, besides saving on electricity bills

How Many Solar Panels Do You Need?

On average, a US household can operate with 15 to 19 solar panels based on 839-886 kilowatt-hours (kWh) of electricity usage/month. This will cover a $140 monthly electricity bill. After the federal credits, installing that number of panels will cost around $12,000 and $17,000. 

However, this is not the ultimate because the requirements vary from person to person. 

Here are a few questions you can ask yourself to answer — how many solar panels do I need? 

  • What is the cost of solar panel installation?
  • What is the average size of the panels and the average size of the roof?
  • What is my monthly electricity usage?
  • How much sunlight does my home get?
  • What is the condition of my roof? 
  • Can my home roof bear the weight of the solar panels?
  • How much will the solar panels cost me after the government tax credits?
  • How efficient is the solar system?

Going solar has one goal — a 100% offset of the electricity bills, so your system meets the required energy usage. Remember, it is a misconception to gauge your solar needs based on finances alone. Similarly, purchasing the system outright without following up on the solar panels calculator is also a bad decision. Needless to say, estimating the correct number of panels is vital for efficient energy adoption.

*Solar installation is a customized process. The solar company can better assess your needs and suggest the number of panels accordingly.

Calculate The Number of Solar Panels to Power a Home

While most companies provide a solar power calculator for their customers, you can get the estimate on your own by following these instructions step-by-step.

Step 1: Determine your energy use

An average American roughly uses 10,632 kilowatt-hours (kWh) of energy per year. Check your last month’s bill for this solar estimate. Factor in the daily energy consumption of all your household appliances. According to EcoWatch, the table below mentions the total estimated energy consumption by major household appliances:

Step 2: Check the availability of sunlight

Measure the amount of sunlight in your area during the peak sun hours. The United States of America receives 4.2 hours of peak sunlight on average, for roughly 128 months. More sunlight means fewer solar panels for power production.

Major companies offer a solar estimate to their customers with their advanced solar power calculator so they can easily understand how many panels are needed for installation at home. 

Step 3: Check the energy produced by the solar panels 

Evaluate the total peak sun hours to determine the total kilowatt-hours of energy production from the solar panels. Consider the solar panel size in watts and multiply it by the sunlight your area receives to check the monthly electricity production. Convert this from watt-hours to kilowatt-hours by dividing by 1000 to match the energy consumption from your bills. 

Take a look at the formula: 

Solar panel size (in watts) x Peak sun hours = Solar power generated monthly 

Remember, areas with more sunlight generate more electricity. Sunlight is a vital solar estimate. Read about the sun score of your house here. Also, solar panels with low wattage generate less electricity than the high-wattage ones. 

Step 4: Calculate the number of solar panels needed 

Now that you know how much energy the panels can produce, it is time to calculate how many solar panels do I need. 

Divide the energy consumed by the total energy generated by one solar panel. This is the kind of correct solar panel calculator that gives you the proper solar estimate of how many panels your home will need.

Here is the formula: 

Total number of solar panels = Total kilowatt-hour energy consumed/Total electricity generated  

Voila, you now have the answer to your question  — how many solar panels do I need? 

Another solar panel calculator offered by Energy Sage includes this formula which can be used by residential solar customers. 

Quantity of solar panels =  system production/panel wattage/system size

As mentioned above, according to the US Energy Information Administration (EIA), an average American household uses 10,632 kWh of electricity per year (or 886 kWh per month). Well-rated solar panels have 300-400 W power (Wattage is measured in watts). The production ratio for solar panels in the US is mostly between 1.3 and 1.6. 

You can also get help from the experts who use a solar panel calculator to ensure all solar energy needs are covered.

Cost of Solar Panels in the US

In 2023, the average cost of installing a 10 kW residential solar panel in the US is $20,650, after taking the 30% federal tax credits into account.

Number of Solar Panels For Specific System Sizes

*The information is taken from EnergySage and the numbers are based on the assumed solar panel wattage is 400 W with a production ratio of 1:6. The efficiency of the panels will also depend on the availability of sunlight in the region.

Number of Solar Panels and the Home Size

*This is a ballpark estimate given by EnergySage.

Number of Solar Panels and the Roof Size

*This information is taken from EnergySage.

Our Advice

Get started with our solar power calculator to plan and analyze your home solar panel requirements. At Solarblocks, our team of energy experts and professional installers will guide you through the process, to fit the right quality of solar panels to power your home. 

Drop us an email at info@solarblocks.us to get your queries resolved.


  1. How many solar panels do I need?

While there is no single answer to this, the need for solar panels varies according to an individual household's need, their overall energy consumption, the location of the property, monthly electricity usage, the size and type of the roof, its condition and orientation, etc. You can get an estimate by using the solar panel calculator offered by most reputable solar companies. 

  1. Can I power an entire home on solar?

Yes, you can run a whole house on solar power. However, the solar panel installation should meet the basic requirements for maximum energy generation — an abundance of sunlight, no shade, perfect roof orientation like a south-facing roof, etc. Use the solar power calculator for a better estimation. 

  1. Do you still receive an electricity bill after installing solar panels?

Yes, once you install the solar system, you will receive an electricity bill, however, the charges will be much less compared to using the grid electricity from a utility provider. Consider the size of your residential solar system to save money or get a proper solar estimate from reputable solar installers to control your energy use. You can also use a solar battery to offset your electricity bills and use stored solar energy during peak hours. 

  1. How many solar panels do you need to power a 1000-square-foot home?

The average electricity required to power a 100 sq. ft. home in the US is approximately 4710 kWh. 8 solar panels will be sufficient to cover this requirement. 

  1. What is the cost of solar panel installation in the US?

In 2023, the average cost of installing residential solar panels in the US is $20,650 for a 10 kW system. This is after accounting for the 30% solar tax credits. 

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