How Many Solar Panels to Power a House?

By PropertyClub Team
May 17th 2024
Figuring out how many solar panels are needed to power a house depends on various factors like your energy usage, roof direction, and the amount of sunlight your location receives. In this article, we’ll explain the key considerations and provide a guide to help you estimate the number of panels you might need.

We will also look at how much power solar panels can produce, the number of panels required based on your home’s square footage, and the costs involved. By understanding these details, you can make an informed decision about switching to solar energy and possibly even go 100% off-grid.

hash-markTable of Contents

Number of Required Solar Panels Considerations
How Much Power Can a Solar Panel Produce?
Estimating Solar Panel Requirements by Home Size
Calculating Required Number of Solar Panels
How Large Does My Solar Array Need to Be?
How Many Solar Panels to Power a House? The Bottom Line
Number of Solar Panels to Power a House FAQs

hash-markNumber of Required Solar Panels Considerations

Several factors determine the number of panels required for a 100% solar-powered home, including but not limited to the following:

  1. Total Energy Usage: Analyze your monthly and yearly energy consumption to determine your overall needs
  2. Average Amount of Sunlight: Consider the typical sunlight hours your location receives daily and seasonally.
  3. Roof Direction and Tilt: South-facing roofs with an optimal tilt angle receive more sunlight.
  4. Shade and Obstructions: Evaluate any potential shading from trees, buildings, or other structures.
  5. Energy Efficiency of Your Home: More efficient homes require less energy and therefore fewer panels.
  6. Type and Efficiency of Solar Panels: High-efficiency panels produce more energy per square foot.
  7. Roof Size and Shape: Ensure there is adequate space to install the required number of panels.
  8. Local Climate and Weather Patterns: Frequent cloudy or rainy days can reduce solar energy production.
  9. Battery Storage Capacity: Adequate storage ensures you have power during nighttime or cloudy periods.
  10. Local Regulations and Incentives: Be aware of building codes, zoning laws, and available financial incentives that can impact your solar installation.

To determine your overall energy needs, you can look at your energy bills and make a note of how many kWh you use each month. With respect to the roof, southern-facing roofs tend to get the most sunlight, and the Southwest receives more sunlight than other areas of the country, such as the Northeast.

According to the US government’s Environmental Impact Assessment, the average American household uses approximately 877 kWh of electricity per month, which comes out to about 10,600 kWh per year. This figure is an average and can vary depending on the size of the home and individual energy consumption. 

You can work with a solar professional to determine how many watts you need each panel to produce, and they can help you find options. 

hash-markHow Much Power Can a Solar Panel Produce?

A standard solar panel can produce approximately 250 watts per hour of sunlight. With advancements in solar technology, consumer-grade panels have become highly efficient. The exact amount of power your solar panels can produce depends largely on the amount of sunlight they receive, which is influenced by the panel’s orientation and your geographic location.

Assuming your panels receive at least 6 hours of sunlight a day, each panel can generate about 1.5 kWh of power per day (250 watts x 6 hours). This translates to roughly 45 kWh per month and about 540 kWh per year per panel. Given that the average American home uses around 900 kWh per month, you would need at least 20 solar panels to meet your energy needs.

However, it's important to note that you will likely need more than 20 panels since consistent 6-hour daily sunlight exposure is rare. Factors such as weather, shading, and seasonal variations can reduce the amount of sunlight your panels receive, necessitating additional panels to ensure you generate enough power year-round.

hash-markEstimating Solar Panel Requirements by Home Size

Determining the number of solar panels needed to power your home can depend significantly on the size of your house. Larger homes generally consume more energy, requiring more panels to meet their energy needs. Additionally, factors such as the home's energy efficiency, the average amount of sunlight the location receives, and individual energy consumption habits play a crucial role in this estimation.

Here are some average estimates for the number of solar panels needed to power homes of various sizes:

  • For a 1,000 sq. ft. home: 10-12 panels
  • For a 1,500 sq. ft. home: 16-18 panels
  • For a 2,000 sq. ft. home: 22-24 panels
  • For a 2,500 sq. ft. home: 28-32 panels
  • For a 3,000 sq. ft. home: 34-38 panels

These estimates provide a general idea but can vary based on specific conditions and needs.

hash-markCalculating Required Number of Solar Panels

While hiring a professional for a quote is the best option, you can estimate the number of solar panels you need with some basic math:

  1. Determine Average Monthly Electricity Usage: Refer to your last 12 electricity bills to find your average monthly energy consumption.
  2. Determine Daily kWh Usage: Divide your average monthly usage by 30. For example, 1,000 kWh per month / 30 days = 33.3 kWh per day.
  3. Estimate Daily Sunlight Hours: Determine the average hours of direct sunlight your panels will receive per day. Aim for at least 4-5 hours for a 250-watt panel.
  4. Determine Power Offset: Decide the percentage of your energy you want to replace with solar power (e.g., 100%, 75%, 50%, or 25%) and multiply this by your daily kWh usage.
  5. Calculate the Number of Panels Needed: Divide the number from step 4 by 250 (since 1 panel = 250 watts). This gives a rough estimate of how many panels you need.

Keep in mind that you may need more panels than calculated, as they may not receive consistent sunlight every day.

hash-markHow Large Does My Solar Array Need to Be?

All other things being equal, homes in sunnier areas require a smaller array than homes in areas that do not receive as much sunlight. For example, the average size of a solar array in California is smaller than one in Massachusetts because California gets more sun than the Northeast. 

A typical solar panel for residential use takes up about 15 sq. feet. For a standard 5 kWh system (~20 panels), you would need about 300 square feet of space. For a 10 kWh system, you would need about 600 sq. feet, and for a 15 kWh system, you would need around 900 sq. feet. 

These calculations were made assuming your panels have a 16% energy efficiency. Most residential panels hover between 16%-20% efficiency. If you have more efficient panels, then you would need less space. 

(Fun fact: the theoretical maximum efficiency for a single panel solar cell using today’s technology is 33.7%. This figure is called the Shockley-Queisser limit). 

hash-markHow Many Solar Panels to Power a House? The Bottom Line

Switching to solar power is a significant decision that involves various factors, from your home’s energy consumption to the amount of sunlight your location receives. By understanding your energy needs, the efficiency of solar panels, and local conditions, you can make an informed decision about the number of panels required to power your home. Consulting with a solar professional can provide a more precise estimate and help optimize your setup.

Embracing solar energy not only reduces your electricity bills but also contributes to a sustainable and eco-friendly future.

hash-markNumber of Solar Panels to Power a House FAQs

1. Can You Run a House Entirely on Solar Power?

Yes, it's certainly possible to run a house entirely on solar power with the proper setup. You'll need a sufficient amount of solar panels and solar batteries to be able to go 100% off-grid. 

2. How Many Solar Panels Do I Need For a 3 Bedroom House?

You'll need approximately 26 solar panels for an average 2,300 square foot 3-bedroom house. The exact number will depend on the size of your home, your energy use, and the average number of sunlight hours you receive. 

3. How Much Does a 20-panel Solar System Cost?

The national average for a 20-panel solar array that produces around 6 kW will cost is approximately $18,000. This means your costs will be around $3 per watt, although the exact cost will vary depending on the quality of panels you purchase and the labor and installation costs in your state. 

4. Can AC Run on Solar Panels?

You can run air conditioning on solar power, but for constant cooling, you'll need to have solar batteries installed, or switch to grid power during the night as solar panels only provide power while getting sunlight.