How many solar panels do I need for my home?

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Determining the size of your solar energy system starts with a simple question: how many solar panels do I need for my home? As most people want to produce enough energy to completely eliminate their electricity bill, the first step is determining what size solar system will produce enough power to meet your household consumption levels. Ultimately, you will be calculating how many kilowatt hours of power you will need and finding the correct system size and number of panels to power your house. 


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How many solar panels do I need?

If the average household consumes 11,000 kWh per year and we assume 250 watt solar panels, we can use the high and low panel production ratios to calculate an average. Thus, the typical homeowner will need 28 – 34 solar panels to cover 100% of energy usage (dependent on location and roof size).

For those wondering how we estimated those numbers for energy consumption and required number of solar panels, here’s the breakdown. When you want to understand how much power you’ll need, start by looking at how many kilowatt hours (kWh) of electricity you use in a year. Most utilities provide you with your total power consumption for the last twelve months on your monthly bill. To offer some perspective, one kWh is 1,000 watts of power being used in an hour. So, if you have 20 lights in your home and they all use 50-watt bulbs, having every light on in your house for one hour would use up one kWh of electricity. According to the latest data from the U.S Energy Information Administration, in 2013 the average American household used 909 kWh per month. Said differently, the average American household consumes just under 11,000 kWh per year.




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In order to find a range for number of solar panels, we compared Arizona and Maine’s solar panel production ratios, 1.31 and 1.61, the highest and lowest in the U.S.. We then took 11,000 kWh and divided it by the respective ratios and then divided that number by 250 (the typical panel wattage). That calculation gave us high and lows for the average number of panels a homeowner will need.

How many kWh can your solar panels produce?

The amount of power (kWh) your solar energy system can produce depends on how much sunlight exposure your roof receives. The amount of sunlight you get in a year depends on both where you are in the country, and what time of year it is. California has more sunny days annually than New England. But in either location, you’ll be able to produce enough power to cover your energy needs! If you live in an area that gets less sun, you’ll just need to have a larger system installed at your home.

Two comparably sized households in California and Massachusetts consume the average amount of electricity for an American household, about 11,000 kWh annually. The California household needs a 7.0 kWh system to cover 100% of their energy needs. By comparison, the comparable household in Massachusetts needs a 8.8 kWh systems to cover their energy needs. Solar panel systems in California are smaller than the solar panel systems in Massachusetts, but are able to produce the same amount of power because they’re exposed to more sunlight each year. Homeowners in less sunny areas, like Massachusetts, can make up for this disparity by simply using more efficient panels or increasing the size of their solar energy system, resulting in slightly more solar panels on their rooftop!

In order to offer comparison data on how many panels and how much power you will need, we’ve compiled a table that compares average annual energy need to estimate the number of panels required to offset typical energy demand. We looked at data for the 6 most common system sizes that we see active in the EnergySage Solar Marketplace. In order to calculate the below data, we averaged annual kWh production in the top 12 solar states and assumed standard 250 watt panels in order to calculate how many panels you would need. The average system size in the U.S. is 5kW (5000 watts) so you can use that as a benchmark if you’re unclear on what your power needs will be.

How many solar panels will I need? System size comparison table

System Size Average Annual KWH production Estimate number of solar panels
3.5kW 4,954 14
5kW 7,161 20
7kW 9,909 28
10kW 14,165 40
12kW 16,987 48
15kW 21,234 60

The table above assumes that you’re using standard-efficiency panel. However, the number of panels you need to power your home, and the amount of space that your system will take up on your roof, will change if you’re using lower-efficiency economy panels or high-efficiency premium panels. Below is a table that will give you a sense of how much space your system will take up on your roof, whether you choose economy, standard, or premium panels.

How many solar panels can I fit on my roof? System size compared to square footage table

System Size Economy Panels (sq ft) Standard Panels (sq ft) Premium Panels (sq ft)
5 kW 306 254 224
10 kW 612 508 448
15 kW 918 763 672
solar panel system size infographic

The average size of 5, 10, and 15 kW solar panel systems using standard panels.

Perhaps one of the most difficult aspects of sizing a solar panel system is estimating annual energy usage for your household. A number of larger consumer products or add-ons can significantly change your annual kilowatt hour requirements and thus can greatly impact how many panels you will need. For example, if you’ll be running central air conditioning or powering a heated swimming pool in your backyard, the size of your solar panel array could be drastically altered. To get a feel for the energy impact of various products you may have or may be considering for your home, check out this table comparison.

How many solar panels will I need for common household products?

Consumer ProductAverage Annual KWH RequiredEstimate number of solar panels needed 
Refrigerator6002
Air Conditioning Unit215<1
Central Air Conditioning1,0003
Electric Vehicle3,00010
Heated Swimming Pool2,5008
Hot Tub (outdoor)3,30011

From reviewing the various kWh requirements for everyday household appliances and products, one thing is clear: certain add ons will dynamically change monthly energy use and solar panel system size. For example, pairing your electric vehicle with solar panels is a great way to reduce carbon emissions and improve energy efficiency, however, it should be planned accordingly considering it could potentially double the size of your pv system. Though it is certainly possible to install a solar system and then add more panels later on to accommodate increased energy needs, the most pragmatic option is to size your system as accurately as possible based on your expected purchases such as an electric vehicle, swimming pool or central air system. Asking yourself “how many solar panels will I need for my refrigerator, my hot tub” and etc is a great habit for any new solar homeowner.

Three Tips for Solar Shoppers

  1. Homeowners who get multiple quotes save 10% or more

    As with any big ticket purchase, shopping for a solar panel installation takes a lot of research and consideration, including a thorough review of the companies in your area. A recent report by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) recommended that consumers compare as many solar options as possible to avoid paying inflated prices offered by the large installers in the solar industry.

    To find the smaller contractors that typically offer lower prices, you’ll need to use an installer network like EnergySage. You can receive free quotes from vetted installers local to you when you register your property on our Solar Marketplace – homeowners who get 3 or more quotes can expect to save $5,000 to $10,000 on their solar panel installation.

  2. The biggest installers typically don’t offer the best price

    The bigger isn’t always better mantra is one of the main reasons we strongly encourage homeowners to consider all of their solar options, not just the brands large enough to pay for the most advertising. A recent report by the U.S. government found that large installers are $2,000 to $5,000 more expensive than small solar companies. If you have offers from some of the big installers in solar, make sure you compare those bids with quotes from local installers to ensure you don’t overpay for solar.

  3. Comparing all your equipment options is just as important

    National-scale installers don’t just offer higher prices – they also tend to have fewer solar equipment options, which can have a significant impact on your system’s electricity production. By collecting a diverse array of solar bids, you can compare costs and savings based on the different equipment packages available to you.

    There are multiple variables to consider when seeking out the best solar panels on the market. While certain panels will have higher efficiency ratings than others, investing in top-of-the-line solar equipment doesn’t always result in higher savings. The only way to find the “sweet spot” for your property is to evaluate quotes with varying equipment and financing offers.

For any homeowner in the early stage of shopping for solar that would just like a ballpark estimate for an installation, try our Solar Calculator that offers up front cost and long term savings estimates based on your location and roof type. For those looking to get quotes from local contractors today, check out our quote comparison platform.





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 So, what do I read next?
How to Evaluate a Solar Panel
What Questions to Ask Your Installer
Should I Buy or Lease My System



12 thoughts on “How many solar panels do I need for my home?

  1. Jackie Oliver

    I really like what you said about looking into how many solar panels you need. I never would have known that you need anywhere from 28 to 34 solar panels. However, I love the idea of having panels cover 100% of my energy usage.

    Reply
  2. Johanson Ugalde

    Hi I love you web page.
    I will like to know how many panels do I need to run a refrigerator, portable ac and a tv.
    I live in usa but I will like send this panels to Costa Rica it has a pretty much California weather.
    Do I need batteries if is so how many?
    Thank you

    Reply
  3. william c hassell

    I live caribbean i am getting about 10 hours sun per day, i consume about 565 kwh per month, how many panels do i need and how much the cost is per panel ,my concrete roof size is about 2600 square foot, and what do you do during the night to continue to get power.

    Reply
  4. John Duffy

    What is sq footage for (1) panel? I’m building a 4700 sq ft log cabin in smokey mtns, TN. I’ll have approx. 1800 sq ft metal roof. Propane fireplace and stove, CH & air. How many panels do I need?

    What do panels cost? Would buying expensive panels reduce the number of panels needed?

    Reply
    1. Sara Matasci

      A standard 60-cell solar panels will measure approximately 3 ft x 5 ft (or 15 sq. ft.). Buying more expensive, higher-efficiency panels (like SunPower) can reduce the number of panels you need, but they aren’t always cost-effective. EnergySage’s Solar Calculator can give you a sense of how much you’ll pay for panels, as well as how much you’ll save.

      –Sara
      Content @ EnergySage

      Reply
  5. Pingback: Are Solar Panels Recyclable? - Earth911.com

  6. Michael

    Thank you for a very informative web site. I’m new to the solar world, being someone who has recently purchased a home,but I am eager and seeking more knowledge on becoming sustainable with my energy usage and needs.

    Reply
  7. Steve Stout

    I have a somewhat backward calculation. To charge a 6.5KWh battery in an hour using solar do I need 26 panels x 250w each = 6.5KW?

    Reply
    1. Phule

      No the conversion of D.C. To ac or vice versa will take 30 percent of your power so if you get 300 watt panels you actually only produce 210 hope this explains it. Just take 30 percent off what the panels say they produce. And of course sun exposure has a ton to do with it

      Reply

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