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

The short answer is the typical homeowner needs 28 – 34 solar panels to cover 100% of his or her electricity usage.

The range is fairly broad because solar panel need depends on many factors, including geographic location, the type of panels, and the household’s energy consumption pattern.

The 28-34 solar panel estimate is determined by using high- and low panel production ratios to calculate the average solar panel need. It also assumes that the average household consumes 10,400 kWh per year, and that the panels are 250-watt solar panels.

How to calculate your own solar panel estimate

Estimating needed energy consumption and the required number of solar panels starts with calculating how much power your household needs.

Start by researching how many kilowatt hours (kWh) of electricity your household uses in a year. Most utilities show your aggregate power consumption over the last twelve months on your monthly bill. 

To gain some perspective, one kWh is 1,000 watts of power being used per hour. So, if you have 20 lights in your home that use 50-watt bulbs, having every light on in your house for one hour would use up one kWh of electricity (50*20).

The most recent data from the U.S Energy Information Administration shows that the average American household used 897 kWh, which works out to just under 11,000 kWh per year.

Once you know your kWh per year, you can estimate how many solar panels will be needed. Since climates have differing amounts of sunlight, we compared Arizona’s and Maine’s solar panel production ratios, which are 1.31 and 1.61, because they are the highest and lowest in the U.S.

Then, we took 11,000 kWh and divided it by the respective ratios and then divided that number by 250 (the typical panel wattage). This calculation gives the highs and lows for the average number of panels a homeowner will need.

How many kWh can your solar panels produce?

This depends on the amount of sunlight exposure your rooftop receives. The amount of sunlight you get in a year depends on both your geography and the season. For example, California has more sunny days annually than New England.

Despite the sunlight difference, you can produce enough power to cover all of your household energy needs! If you live in an area that gets less sun, such as Maine, Seattle, or Portland, Oregon, you simply need to install a larger system.

For example, two comparably sized households in California and Massachusetts consume the average amount of electricity for an American household, about 10,400 kWh annually.

Yet the California household needs a 7.0 kW system to cover all energy needs, while the comparable Massachusetts household needs an 8.8 kWh system to cover all energy needs. 

Solar power systems in California are simply smaller than the solar panel systems in Massachusetts but produce the same amount of power because California households are exposed to more sunlight each year.

Homeowners in less sunny areas, like Massachusetts, make up for this disparity by employing more efficient panels or increasing the size of their solar energy system. Though the sunlight difference for the regions is large, those in cloudy areas only need slightly more solar panels on their rooftops!

How many solar panels power a house key takeaways

  • An average house needs 28 to 34 solar panels to fully offset electricity bills with solar
  • The number of solar panels you need for your house depends on factors like location and panel performance
  • Compare solar quotes to get the best customized solution for your property’s needs

How many solar panels do I need for my house? System size comparison

SYSTEM SIZE (KW)AVERAGE ANNUAL PRODUCTION (KWH)ESTIMATED NUMBER OF SOLAR PANELS
3.5 kW4,95414
5 kW7,16120
7 kW9,90928
10 kW14,16540
12 kW16,98748
15 kW21,23469
SIZE (KW)LOW EFFICIENCY PANELS (SQ. FEET)MEDIUM EFFICIENCY PANELS (SQ. FEET)HIGH EFFICIENCY PANELS (SQ. FEET)
5 kW306254224
10 kW612508448
15 kW918763672
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

Tips for reducing solar energy costs

Solar panels are a big ticket household item. As such, making an informed purchasing decision takes research and thorough consideration. A thorough review of the companies in your area is a great place to start.

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 they can. This is the best way to avoid overpaying. Often, large installers charge inflated prices, so comparison shopping is key.

Smaller contractors typically charge lower prices. To find a reputable one, you’ll need to use an installer network like the one below:

The biggest installers typically don’t offer the best price

The bigger isn’t better mantra applies to the solar industry. Large brands can afford expensive advertising, but that does not make their services a superior value. A recent report by the U.S. government found that large installers are $2,000 to $5,000 more expensive than small solar companies.

It’s important to compare those big installer prices with smaller installers. By checking with multiple local installers, you can ensure you pay a fair installation price.

Comparing all your equipment options is just as important

National-scale installers have higher prices, and they tend to have fewer solar equipment options. This lack of selection can negatively impact the ultimate productivity of your solar system.

When comparison shopping, be sure to collect a diverse array of solar bids that compares not just cost but also solar systems. Picking the optimal equipment package can make all the difference.

Many variables must be considered when choosing a solar panel system. While certain panels have  higher efficiency ratings than others, investing in the most expensive solar equipment does not always result in increased savings. To find the “sweet spot” for your property, evaluate quotes with different equipment and financing offers.

Choosing the right number of solar panels for your RV, home, or cabin is a matter of calculating your average kWh usage on an annual basis and comparing it to the number of panels needed to generate that level of power in your climate.

Sunny climates need slightly fewer solar panels to run a given number of annual kWh. If you live in a cloudy place, you’ll only need slightly more panels to handle your electricity needs.

Once you have determined the number of panels needed, it is time to shop around. Checking with multiple vendors is very important. Large installers have the budgets needed for costly advertising, but they may not offer you the best value. To get the lowest cost, check with multiple installers, both big and small.

In addition to lower pricing, small, local installers may provide more options. A bigger installer often has cookie-cutter solar systems, which may not be the ideal choice for your situation. Check with a variety of installers with different equipment options to find the one that best suits your home.

The sun is an incredible resource. Why not use it to power your home? Though the initial solar panel installation may be costly, tax benefits and the energy bill savings over time allow solar panels to pay for themselves. To get started, contact several solar power contractors to start the bidding process today.

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