If you’re a homeowner who is considering making the jump to residential solar panels for your home, you probably have plenty of questions about home solar and how it works. “How many solar panels do I need?” is one of the most common questions homeowners ask, and for good reason. Installing solar panels is a big investment, and you want to make sure you’re getting the most bang for your buck. However, you also want to make sure that when you do go solar, you won’t be stuck with decades’ worth of debt because your panels produce way more energy than you need.
The right number of solar panels for your home will vary depending on a few key factors, including the size of your home, your energy usage, the number of hours of sunlight your home gets on average, and the climate you live in. In this article, we’ll break down all the factors you need to consider to determine how many solar panels you need to power your home.
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How to Calculate How Much Solar Power You Need
The first step in calculating how many solar panels you need is to determine your home’s power usage. The average home uses about 910 kilowatt-hours (kWh) of electricity per month. If you have a home with an average number of square feet, you’ll need to invest in a solar power system that is able to produce about this much power. However, the amount of power that you need for your home might vary depending on factors like the size and location of the home, the number of occupants, and energy efficiency of your solar panels.
You can check your last few electricity bills to get an idea of your home’s energy usage and electricity consumption, or you can use an online calculator. From there, you need to figure out the wattage and production ratio of solar panels needed. These details will tell your production ratio, which shows you how powerful the solar energy system you install on your property needs to be in order to see a sizable reduction in your monthly electric bill.
For example, let’s say you have a 10 kW system, and it produces 16 kWh every year. This translates to a production ratio of 1.6. Now that you know your home’s energy usage and the solar panel wattage and production ratio you need, you can calculate how many panels you need to power your home.
Solar Power Calculation Formula and Steps for Homes
To ensure you choose the right number of panels for your home needs, use the following steps.
- Choose your solar panels: Before you can start calculating the number of solar panels that you want to buy, you need to choose which panels you want to use for your calculations. One panel from one brand might produce one amount of electricity, but not every panel produces electricity at the same rate. Check out a few of the best residential solar panel options here and shop around before you decide how many panels you’ll need.
- Determine your home’s power usage: The average home’s energy bill comes out to about 910 kWh per month, but electricity usage will vary from home to home based on factors like square footage and the number of people living in the house. Check your power bill to see how much energy you use each month on average.
- Determine the solar panel wattage you need: This is the panel’s power rating. A wattage output of 340 is the average, but each solar panel has its own energy production rating. Check the wattage rating on the panel that you’re considering adding to your home’s renewable energy infrastructure or compare a few panels.
- Figure out the solar panel production ratio: This is an estimate of the energy output over time in kilowatt-hours (kWh) to watts (W). Production ratios are rarely, if ever, 1:1, which means that if you want your solar panels to cover all of your electric utility bills, you’ll need more than one panel. If you’re only looking for a partial offset, you won’t need to purchase as many solar panels to achieve your goal.
- Calculate how many panels you need to power your home: In order to generate 100% of your home’s energy needs with solar power, most homes will need about 28 solar panels. However, most homes only generate a portion of their energy needs with solar power.
- Finalize your calculation in light of your goals: Calculate the final number of solar panels you need based on the panels you’ve chosen and your home Once you’ve considered all of the above factors, you can calculate the final number of solar panels you need to power your home completely or cut a large percentage of your power bill.
After taking all these factors into consideration, you should have a good idea of how many solar panels you need to power your home. If you’re still not sure, you can always consult with a solar professional to get a more accurate estimate.
Factors that Determine Solar Panel Output
Calculating the number of solar panels that you will need isn’t an exact science. There are a few factors that will affect the output of your solar panels and how many you need to power your home, and these considerations go beyond what you can calculate on paper. Be sure to consider factors like the following when determining how many solar panels you’ll need for your system.
- Climate: Solar panels work best in sunny climates, as they need direct sunlight to generate power. If you live in an area with very little sun, you may need more panels to generate the same amount of power as someone who lives in a geographic location that receives regular, direct sun. If you live in a state that doesn’t get as much sunlight, you might want to consider adding a solar battery to your system, which helps store excess power during periods of overcast.
- Orientation: The orientation of your solar panels also affects their output. Solar panels should be facing south if you live in the northern hemisphere, and north if you live in the southern hemisphere, in order to maximize their exposure to the sun. Even if your solar system size forces you to utilize multiple sides of your roof, try to keep the majority of your panels facing the sun in order to maximize their output.
- Angle: The angle of your solar panels also affects their output. Solar panels should be installed at an angle that is perpendicular to the sun’s rays. This allows them to absorb the most sunlight and generate the most power.
- Shade: Shade from trees, buildings, or other objects can reduce the amount of sunlight your solar panels are exposed to, which will reduce their output. If you have a lot of shade on your property, you may need more panels to generate the same amount of power as someone with no shade.
- Time of Year: The seasons that the sun is out the most tend to be the best time of year to have solar panels.
Now that you know all the factors that affect solar panel output, you can calculate how many solar panels you need to power your home. Make sure to consider your state’s solar tax credits if available, which can help you supplement your system’s needs if you live in a state that isn’t known for constant sunshine.
How Many Solar Panels Are Needed to Run a House?
So, how many solar panels do you really need if you want to eliminate your power bill completely? While the specifics of your panel number calculation will vary depending on the factors we’ve discussed above, here are the average number of solar panels that you’re likely to need in order to power your home based on national power consumption averages.
|Home Size||Average Energy Consumption per Month (kWh)||Panels Required|
|500 sq ft||633 kWh||14-17|
|1,500 sq ft||919 kWh||18-21|
|2,000 sq ft||1,141 kWh||22-25|
|2,500 sq ft||1,440 kWh||26-28|
|3,000 sq ft||1,844 kWh||29-32|
Average Solar Panel Cost
The average solar panel cost in the United States is $2.60 per watt. This means that for a typical residential solar system of six kilowatts, the total cost before tax credits would be $15,600. However, if you’re looking to offset a higher percentage of your solar costs with a ten-kilowatt system, you can expect to pay around $26,000. Of course, the final price you pay will depend on many factors, including the following.
- Size of the system: This is the first factor that will affect the average cost of a solar panel installation. Homeowners with larger homes or higher energy usage will need more solar panels to produce enough electricity, and will therefore have a higher total price.
- Solar panel efficiency: The efficiency of a solar array is the percentage of sunlight that is converted into electricity. For example, if a solar panel has a rating of 22, it means that the panel is able to convert 22% of the natural sunlight that hits it into usable electricity for your home. High-efficiency panels will cost more but will produce more power and take up less roof space. They will also pay themselves back in a shorter period of time when compared to less efficient, cheaper solar panels. There is a balance to getting the best value solar panels.
- Location: Solar panels installed in sunny locations will produce more electricity than those in shady areas. A homeowner who lives in a sunnier state may therefore have higher total costs for their system installation but will also see greater savings on their electric bill.
- Type of panels: The two main solar panel types are polycrystalline and monocrystalline. Monocrystalline panels have better efficiency but cost more, so consider this when deciding which type is right for your home.
Some states and utility companies offer solar incentives, which can lower the cost of a solar panel installation. Be sure to research these programs and your state’s laws before you decide on a solar panel system for your home. The specific benefits that you’ll have access to will vary depending on where you live, but these discounts are usually provided as a tax credit toward next year’s state tax filing. This means that, while you’ll usually need to pay full price for your system, you can deduct your credit from your taxable income next year. There are also federal tax credits in place to help you pay for your solar system, but they may not be available after 2023.
System size is one of the biggest factors in determining the cost of solar panels. Homeowners with larger homes and higher electricity bills will need to purchase more expensive systems to offset their energy usage. Conversely, homeowners with smaller homes and lower electricity bills can get by with less expensive systems. The table below summarizes the average cost of solar panel systems of varying sizes.
|System Size (kW)||Average Cost per Watt||Average System Cost|
The average payback period for solar panel systems is in decline. In 2020, the average payback period was between five and eight years, which means that it took at least five years for the most efficient panels to pay themselves back in electricity production. In some states, the payback period is now as low as four years and is continuing to decline as efficiency increases.
If you’re considering going solar, it’s important to compare prices from multiple companies. The price of solar panels varies widely from company to company, and the only way to get the best deal is to compare quotes. Use a solar calculator to get personalized quotes from top solar companies in your area.
The price of solar panels will continue to drop as technology improves and more companies enter the market. In fact, a report released by the International Renewable Energy Agency (IRENA) found that the price of solar panel systems may fall by up to 59% by the year 2025. If you can’t currently fit a residential solar system in your budget, you might want to focus on using other, more affordable methods to improve the value of your home as panel price decreases.
View Other Solar Panels Resources
- How Many Solar Panels Do I Need For My home?
- How Much Power Do I Need To Power My Shed?
- Do Solar Panels Work In The Winter?
- Can You Walk On Solar Panels?
Solar panels are a great way to save money on your electricity bill and reduce the environmental impact of your home’s energy use. If you’re considering going solar, be sure to compare different options from various companies. This will ensure you get the best deal on your solar panel system.
Solar Panels FAQ
How many solar panels does it take to run an average house?
To completely run your home, the average homeowner will need to install 20 to 28 solar panels. However, most homeowners who install solar panel systems on their property do not get 100% of their energy from their panels, as a system this size would be a major upfront investment.
Can solar power run an air conditioner?
Yes, solar power can run an air conditioner so long as your solar panel system is up and running, your inverter makes your panel system compatible with your home energy system, and your air conditioner is plugged into the home system. Your solar panel system must also produce a large enough amount of electricity to cover the power the air conditioner uses.
How much does a 10kW solar system cost?
The average cost of a 10kW solar panel system is around $23,620. However, the price you’ll pay for your system will vary depending on panel efficiency, the number of panels that you need, and your location.
Today's Homeowner’s Solar Companies Rating Methodology
At Today's Homeowner, transparency and trust are our most important values for the reader. That’s why we took the time to create an objective rating system and score each solar energy company/service according to our methodology.
Our research team dug deep into the fine print of contracts, combed through more than one hundred customer reviews, and thoroughly investigated all of each solar energy company’s services, costs, and products. We’ve done the homework for you by researching nearly all of the solar energy companies on the market so you can have the information you need to make the best choice for your home.
We developed a formula to objectively determine the best solar energy companies and give each a score out of 100 based on the following criteria:
Plan Options (30): Do they provide a variety of plan options? We looked at the number of plans each solar energy company offered and the flexibility of adjusting the plan.
Services offered (20): How many services are offered in each plan? We looked at whether the company manufactures its own solar panels, whether it contracts out installation, and what additional products each company offers.
Trust (10): What do customers say after their solar panels are installed? Does this company offer a guarantee? We considered how satisfied customers are post-service if the company does what it says it will, BBB accreditation, and service guarantees.
Prices (10): How reasonable are the costs of the plan or service in comparison to the industry average? We compared the costs of each company to competitors that offer the same solar energy services.
Unique perks (10): Does the company offer discounts or special services such as financial incentives, rebates, or a useful mobile app? We looked for extras each company offers that set them apart from the competition.
Customer Service (10): How is the customer experience when contacting the company? We considered the speed of response, weekend/holiday availability, and ease of communication through phone calls, email, and online chat functions.
Nationwide availability (10): How many states does the company offer its services? Companies that operate nationally and in all zip codes are favored over those with limited availability.