How Many Solar Panels Would Be Ideal For My House?

If you want to power your entire house with solar energy, you’ll need between seventeen and twenty-one panels, according to our calculations. To figure out how many solar panels you need, you’ll need to know:

By first dividing the system size by the production ratio, and then by the panel wattage, you may get the required number of solar panels.

Several criteria, including your location, panel efficiency, the panel rated power, and energy usage habits, will determine the precise number of panels you will need to install. The cost of going solar is strongly influenced by the number of solar panels required to power your home.

The answer isn’t always black and white, but we’ve put together some hypothetical scenarios to help you get a sense of the range of possibilities when trying to determine how many solar panels you’ll need for a practical residential installation.

Note: How many solar panels are needed to power a home?

Figuring Out How Many Solar Panels You Need

There are a few things to keep in mind when you begin to figure out how many solar panels you’ll need:

In What Ways May The Number Of Solar Panels Be Determined?

How many solar panels you need can be estimated by first dividing your annual electricity consumption by the production ratio in your location, and then by the power output of your solar panels. Let’s dissect that a little:

There are numerous variables to consider when determining the optimal number of solar panels for your home. Using our Solar Calculator is the simplest way to determine how many panels are required. We’ll perform the math for you based on your zip code and projected monthly energy costs so you can make a well-informed choice. If you’d prefer to perform these calculations on your own, our formula is detailed below for your convenience.

Our estimate of how many solar panels are needed to provide electricity for your home is based on a model that takes these variables into account. Our working assumptions and calculations are as follows:

Estimated Yearly Electrical Consumption

The quantity of electricity you consume in your home for an entire year is known as your annual electricity usage. This quantity, expressed in kilowatt-hours (kWh), is affected by the electricity-consuming devices in your home and the frequency with which they are used. Electricity is used for a wide variety of products, including refrigerators, air conditioners, minor kitchen appliances, lights, chargers, and more.

The average American home uses 10,632 kWh of electricity per year (or 886 kWh per month), according to the U.S. Energy Information Administration (EIA). We’ll use this number as the ideal solar panel system or solar array size, which would mean you could offset 100 percent of your electricity usage and utility bill with solar panels (in practice, it’s not this neat, but bear with us here). Check your power bills from the previous year to obtain an idea of your typical electricity use if you want a more precise amount based on how much energy you consume. When you have that figure, you can use it in the subsequent calculations.

Power Output Of The Panels You're Looking At Installing

Panel wattage, sometimes called a solar panel’s power rating, is the amount of energy produced by that panel under ideal conditions. Most solar panels have a wattage output of between 300 and 400+, with W standing for “watts.” A recent report found that the most commonly cited capacity range was between 390 and 400 W, thus we’ll be using 400 W panels for our calculations.

The Proportion Of Solar Energy Your System Is Expected To Produce

The production ratio of a solar panel system is the expected energy output over time (in kWh) divided by the size of the system (in W). You can expect a different production ratio from your system depending on the amount of sunlight it receives each day (which is largely determined by your location).

It is not at all unrealistic to observe a production ratio of 1.4 (14 kWh/year generated by a 10 kW system; 14.0 kW/year) in the real world. We’ll use the high and low estimations of these two numbers—1.3 and 1.6—to get the average production ratio in the United States.

Let’s do the math and figure this out.

What does the anticipated number of solar panels for your home look like in light of our three primary assumptions (energy use, solar panel wattage, and production ratios)? This is how the formula breaks down:

System size/production ratio/panel wattage = the number of panels.

When we use the formula we just developed, we get:

Panels x Energy Output (in Watts) = 10,632 kWh (1,3 or 1,6) x 400

This means that the number of solar panels in an array can range from 17 to 21, depending on the output ratio chosen (17 for a 1.6 ratio, and 21 for a 1.3 ratio). Thus, with 17 panels at 400 W apiece, the system output is around 6.8 kW in total!

Cost Of Solar Panels

Cost is not taken into account when deciding how many solar panels to purchase. The average price of a solar panel is $2.95/watt. A 10 kW system typically costs around $20,650 to install (after accounting for the 30 percent federal solar tax credit). Location, installation cost, and incentives all have a role, with warmer climates requiring fewer panels but higher costs.

Principal Factors To Determine How Much Solar Energy You Need

While the aforementioned three variables can be used as a starting point for a solar panel calculation, many other considerations should be taken into account when designing your solar panel system. While planning the optimal solar panel arrangement for your home, it can be helpful to have a firm grasp of production ratios, the correlation between system size and the number of panels, and the influence of dwelling size.

How Much Energy Can Your Solar Panels Generate?

How much sun hits your roof every day determines how much electricity (in kilowatt-hours) your solar panels can generate. The average annual solar exposure varies widely from one location to another and from season to season. In comparison to New England, California enjoys a higher percentage of sunny days each year. Yet regardless of where you reside, you can generate enough electricity to eliminate your utility expenses; if you happen to be in a region with fewer peak sunlight hours, all you have to do is have a more powerful solar array system installed at your home. Hence, the production ratio varies from place to place; in areas with less sunlight, for example, more solar panels will be required to generate the same quantity of electricity.

Consider two similar-sized families in California and Massachusetts; each uses the national average of 10,632 kWh per year in energy consumption. The average California home requires a 6.8 kW system to meet all of its electrical demands. The average Massachusetts home requires an 8.4 kW system to meet its electrical needs. The greater annual exposure to peak sunlight in California allows for smaller solar panel installations to provide the same amount of power as their larger Massachusetts counterparts. Homeowners in less sunny regions, such as Massachusetts, can make up for this discrepancy by installing somewhat more solar panels or utilizing more efficient panels.

How Many Solar Panels Do Different-Sized Systems Need?

If you reside in a region with a production ratio of 1.6, which may be feasible for homes in most parts of California, our lengthy example at the beginning of this essay indicates that a 6.6 kW system would likely cover the average energy usage for an American household.

Let’s go a step further and have a look at some more illustrations. We’re utilizing a production ratio of 1.6. This may be reasonable for consumers in the state of California, but it may be too optimistic for those living in the Northeast or other regions with less sunlight.

Number of solar panels needed for specific system sizes
System size Number of panels needed Estimated annual production
4 kW 10 6,400 kWh
6 kW 15 9,600 kWh
8 kW 20 12,800 kWh
10 kW 25 16,000 kWh
12 kW 30 19,200 kWh
14 kW 35 22,400 kWh

However, the number of panels you need to power your home and the amount of space your system will take up on your roof will change if you use lower-efficiency panels or high-efficiency panels, as shown in the table, which assumes that you are using 400 W solar panels and your production ratio is 1.6 (which generally correlates to low and high power ratings, respectively).

Estimating your annual energy use is one of the trickiest parts of sizing a solar panel setup. The quantity of panels you’ll need to install depends heavily on your annual kWh needs, which can be drastically altered by a few larger consumer products or additions. The size of your solar panel array, for instance, would need to be adjusted significantly if you utilize central air conditioning or power a heated swimming pool in your backyard. Evaluate the energy effect of the things you currently own or are considering purchasing to get a sense of the size you’ll require.

How Much Space Do You Have On Your Roof?

In the end, the number of panels you can install is limited by the available space on your roof. The table below will give you an idea of how much space on your roof your system will need based on the amount of power generated by the solar panels you choose.

Square footage of different size solar panel systems
System size 300 W panels
(sq. feet)
340 W panels
(sq. feet)
360 W panels
(sq. feet)
400 W panels
(sq. feet)
4 kW 234 207 195 176
6 kW 351 310 293 264
8 kW 468 413 390 351
10 kW 585 517 489 439
12 kW 702 620 585 527
14 kW 819 723 683 615

The size of solar panels is an essential factor to think about if your property is small or has an irregularly shaped roof. Homeowners with smaller roofs need to be able to use fewer small high-efficiency panels, such as those from SunPower, LG, or REC, to attain optimal output, while those with larger roofs may be able to sacrifice some efficiency and buy larger panels to achieve the desired energy output.

How Does The Size Of Your House Affect How Many Solar Panels You Need?

Solar panel sizes have stayed about the same over the past few years, but their power production has improved substantially. The panels are kept tight, efficient, and aesthetically beautiful by the use of an invisible frame and mounting hardware by companies like SunPower. To get a rough idea of how many solar panels your house would need based on its size, consult the table below (assuming 400 W solar panels and a production ratio of 1.6).

Home square footage compared to the number of solar panels needed
Home size Estimated annual electricity needed Number of solar panels needed
1,000 sq. feet 4,710 kWh 8
2,000 sq. feet 9,420 kWh 15
2,500 sq. feet 11,725 kWh 19
3,000 sq. feet 14,130 kWh 23
How Many Solar Panels Do Common Appliances Require?

If you look at the kilowatt-hour (kWh) needs of common home items, you’ll notice that some upgrades can have a major impact on your monthly energy use, which in turn can have a major impact on the size of the solar panel system you should install. Pairing your electric vehicle with solar panels is an excellent way to lessen your impact on the environment and boost your system’s efficiency, but you’ll need to conduct some careful calculations first.

Although it is possible to install a solar system and then have a solar installer add more panels later to accommodate increased energy needs, it is more practical to size your system as accurately as possible based on anticipated purchases, such as an electric vehicle, swimming pool, or central air system. Any new solar homeowner should get into the habit of wondering, “How many solar panels will I need for my refrigerator, my hot tub, etc.”

Solar panel requirements for individual appliances
Product Average annual electricity needed Number of solar panels needed
Refrigerator 600 kWh 1
Window Air Conditioning 215 kWh 1
Central Air Conditioning 1,000 kWh 2
Electric Vehicle 3,000 kWh 5
Heated Swimming Pool 2,500 kWh 4
Hot Tub (Outdoor) 3,300 kWh 6


The energy needs, location, roof size and orientation, and panel efficiency are just some of the variables that go into determining the optimal amount of solar panels for a home. A qualified solar installer can evaluate these aspects and advise you on the ideal configuration of solar panels to meet your energy needs.

Purchasing solar panels is a good long-term investment because it helps lower your carbon footprint and your electric bill. Choosing the right amount of solar panels for your home’s needs requires careful consideration of a variety of factors and the advice of professionals.

At Sun Services USA, we manage the entire process, including site survey, engineering, utility applications, and installation! Even if there are no significant updates, we’ll check in with you once per week to keep you informed. If you have any queries or require assistance, please get in touch with our team.

Frequently Asked Questions

Even after solar panels are installed, you will still have to pay for electricity regularly. But it ought to be less than zero or even negative! After installing solar panels, if you still have high utility bills, you may want to reevaluate the size of your system. Your solar energy system’s capacity may be inadequate now that additional electrical loads have been introduced (such as an electric vehicle).

Off-grid solar battery storage is the only way to avoid electricity costs, but most of the time it’s best to have your solar energy system connected to the grid, even if you install battery storage.

The high initial expenses and intermittent nature of solar power (it can’t be used at night) are two of the industry’s biggest drawbacks. Thankfully, this issue can be addressed to a certain extent via battery storage.

Solar panels are a good investment if you have enough space for them on your roof if you use a significant amount of electricity if you want to reduce your carbon footprint, and if you live in a sunny climate. Solar panels have a high upfront cost, but they pay for themselves over time through savings on electricity costs. Solar will likely become even more beneficial as solar deployment continues to grow (cutting cost) and inflation rates continue to climb.

By first dividing your annual electricity consumption by the production ratio in your area and then by the power output of your solar panels, you may determine how many panels you will need.