As more homes throughout the country consider installing solar panels, one question commonly asked is, “how many solar panels do I need?”. Well, it depends – there are a few factors that go into determining how many solar panels you would need to power your home or business; home energy usage, roof or property surface area, orientation of your roof and geographic location. In this piece, we’ll break it down for you.
How much solar energy do I need?
When determining how much solar energy you need; your home’s average energy usage is the first thing to look at. According to theU.S. Energy Information Administration, in 2019, the average electricity consumption for a U.S. residential utility customer was 10,649 kWh. That’s an average of about 877 kWh per month. To understand your own usage, a good rule of thumb is to look back at your total energy consumption from the last twelve months on your utility bills. Most utility bills provide this information. Divide that number by 12 and you have a great estimate of what you’ll need your solar panels to generate each month.
Where you live also plays an important role in how many solar panels you’ll need. For example, states in the northeast endure longer winters accompanied by shorter days during cooler months. Residents in these regions will most likely need more solar panels to generate the same amount of power as residents from sunnier and warmer climates would. It’s important to understand how many peak hours of sunlight your geographic location receiveson average.
Factors That Affect Solar Panel Output Efficiency
All things being equal, the design of the solar panel determines how efficient it is. This, in turn, specifies how well each square foot can convert sunlight into energy.
For example, gridlines on most panels reduce the active surface area. Therefore, they are not as efficient as those without them. In addition, grid panels are susceptible to peeling, further reducing efficiency.
Quality plays a role, too. For example, if the construction is subpar and introduces corrosion and cracking, it can also impact the ability of the panel to absorb sunlight.
But as a rule of thumb, expect residential solar panels to give you between 150 – 370 watts. This translates to an average solar panel’s wattage per square foot of 15 watts.
How Much Do Solar Panels Cost on Average?
The average cost of a solar panel is around $0.65 to more than $2 per watt for high-end models. That means an average 6 kW system will set you back up to $12,000, depending on the location. This is exclusive of installation costs, which can bump the price up by another $5,000 – $10,000.
As a rule of thumb, PV systems in warmer locations are cheaper but require more panels, while the opposite is true with colder climates.
Fortunately, tax credits and incentives can cut solar panel installation costs and provide further savings throughout their lifespan.
How Many Solar Panels to Power a House?
When estimating how many kilowatts of solar do I need, it’s important to consider the size of your home. A home size of 1500 sqft would consume an avg. of 633 kWh/month, on the other hand, a 3000 sqft home would consume an avg. of 1185 kWh/month. An average homeowner would need about 28 to 34 solar panels to fully offset their electricity usage. The chart below is an estimate of the number of panels you could potentially need based on the size of your home.
*Data from theResidential Energy Consumption Survey.
How many solar panels do I need for a specifically sized solar system?
To determine the number of panels you need to achieve a given solar system size, divide it by the wattage of each panel (which averages around 320 watts).
For example, if you’re aiming for a 4 kW system, you’ll divide 4 kW (or 4,000 watts) by 320 watts to get 12.5. Round up the answer to 13, which is the number of panels you need.
How many solar panels do I need for common appliances?
You can also determine the number of panels you need on a per appliance basis. This approach is helpful if you want to add panels because of increased usage or when buying a new appliance.
To calculate this, divide the average annual wattage of the appliance by the panel wattage. For example, a 600 kWh refrigerator would need two solar panels (600 / 320)
Summary: Step-by-Step Guide to Determining Solar Panel Needs
Here are the steps to figure out the question, “what size solar system do I need?”
1. Measure your annual kWh usage or the yearly electricity consumption of your house. You can either consult a year’s worth of monthly electric bills or use the average American house consumption figure of 10,649 kWh / year as an estimate.
2. Figure out your panel wattage, which is how much electricity your panel produces under ideal conditions. For simplicity’s sake, you can use 320 watts as an estimate.
3. Estimate your production ratio, or how much electricity your panel produces based on the average sunlight. You can compute this by dividing your system wattage by its electricity output in a year. Or you can use the US estimate of between 1.3 and 1.6.
4. Plug the data into the formula: Panel number = kWh usage / production ratio / wattage
For example, let’s say your house has an estimated 12,800 kWh consumption. Assuming a production ratio of 1.6 and 320-watt panels, you would need:
12,800 kWh / 1.6 / 320
Or 25 panels total.
Some homeowners might also ask, “how many square feet of solar panels do I need?” To answer this question, you first need to know that an average residential solar panel is around 17.5 feet. Then multiply this figure by the number of panels you need based on the steps we just outlined.
Thus, in our above example, a 12,800 kWh consumption will need 437.5 square feet of solar panels (or 25 panels x 17.5 feet)
Example Calculations
Before we get into the examples, it’s helpful to note that a home’s power usage isn’t entirely dependent on its square footage. Instead, the number of residents and their energy habits play a much bigger role.
But for the sake of people asking, “how much solar power do I need?” in terms of square footage, we’ve illustrated the examples in these terms.
Example 1: how many solar panels do I need for a 1000 Sq Ft Home?
Let’s assume the consumption of a 1,000 sq ft home with four residents and average usage to be 690 kWh per month or 8,280 kWh per year.
With a panel wattage of 320 and a production ratio of 1.4, the number of solar panels you’ll need is:
Solar Panels = 8,280 / 1.4 / 320 = 18.48
Or 19 solar panels.
Example 2: how many solar panels for 2500 Sq Ft Home?
Let’s assume that our 2,500 sq ft home houses five people with regular energy usage habits. The estimated consumption would then be 1,131 kWh per month or 13,572 kWh per year.
Again, considering a 320W panel and a 1.4 production ratio, plugging the numbers in the equation gives us:
Solar Panels = 13,572 / 1.4 / 320 = 30.29
Or 31 solar panels.
Calculators
Solar Panels kWh Calculator
You can use the calculator below to quickly determine your solar panel needs based on your average monthly kWh usage and the nearest city from your house. The latter helps better gauge the amount of sunlight you receive based on your location.
Solar Panel Square Footage Calculator
Alternatively, you can also figure out the number of solar panels you need based on the square footage. This is useful if you plan to install solar panels on a new house and haven’t tracked your monthly electricity consumption yet.
However, no calculator will do this for you directly since there’s no correlation between square footage and consumption.
But there’s a workaround. You can use the calculator below to get the predicted monthly kWh usage based on the number of people living in the house and their energy consumption habits:
Once you get the estimated monthly kWh usage, simply plug it into the solar panel kWh calculator above.
Not all roofs are suitable for solar panels
Apart from estimating how many solar panels you need, you should also consider the weight of the panels themselves.
On average, a single panel weighs around 40 pounds, adding around 2.8 pounds per square foot for a typical pitched roof and 5 pounds for flat roofs. Therefore, you need to make sure that your roof can support this added weight. You also need to consider the material, age, and structure of your roof.
According to the National Renewable Energy Laboratory of the U.S. Department of Energy, approximately 50% of homes can’t support rooftop solar panels. Community solar programs are a common way for many homeowners, businesses and renters to go solar without actually installing anything on their roof. Participants can subscribe to a nearby solar farm and pay a lower price for the electricity sourced from it. Through Community Solar with Nexamp, the process is similar to determine the size of a subscribers’ share of a solar farm is similar to determining the number of rooftop solar panels. We simply analyze a subscriber’s last 12-13 months of energy usage and recommend a suitable allocation of our farm for them to subscribe to at a discounted rate. The end goal is to offset as much of a subscriber’s annual electricity costs as possible.
At the end of the day, the number of solar panels you’ll need to see potential savings is unique to your home’s energy usage. Interesting in seeing how much you could save by joining our community solar program? Reach out to us by visiting ourcommunity solar pageor call us at(800)-945-5124.
FAQs
How Many Solar Panels Do I Need? ›
You can calculate how many solar panels you need by multiplying your household's hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel's wattage. Use a low-wattage (150 W) and high-wattage (370 W) example to establish a range (ex: 17-42 panels to generate 11,000 kWh/year).
How can I calculate how many solar panels I need? ›You can calculate how many solar panels you need by multiplying your household's hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel's wattage. Use a low-wattage (150 W) and high-wattage (370 W) example to establish a range (ex: 17-42 panels to generate 11,000 kWh/year).
What is the average number of solar panels needed? ›An average homeowner would need about 28 to 34 solar panels to fully offset their electricity usage. The chart below is an estimate of the number of panels you could potentially need based on the size of your home. *Data from the Residential Energy Consumption Survey.
How many solar panels do I need for a 1500 sq ft home? ›A 1500-square-foot home, on average, will need between 14 and 17 solar panels to power the home. This is based on an average energy consumption of 967 Kilowatt hours per month.
How many solar panels do I need for a 2000 square foot house? ›Thankfully, we've got the answer for you! A 2000 square foot house will need 28- 34 solar panels, which comes out to an average cost of \$3.50 per watt. Not only will installing solar panels save homeowners money on their electric bill, but they can also increase the value of their home.
How many solar panels do I need for a family of 4? ›The answer depends on several factors, such as the size of your roof, the type of solar panel system you choose, and how much of your electricity usage you want to cover with solar energy. Generally speaking, a family of four will require anywhere from 3 to 8 solar panels, depending on these various factors.
How many solar panels do I need for a 3000 sq ft home? ›| 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 | 11,775 kWh | 19 |
| 3,000 sq. feet | 14,130 kWh | 23 |
Fact vs Myth: Can Solar Energy Really Power an Entire House? [2023 Update] One of the most frequently asked questions by homeowners in regard to solar power is, “can it really power my entire house?” The answer to that is actually quite simple – yes, solar can indeed power your entire home.
Is 20 solar panels a lot? ›While it varies from home to home, the US households typically need between 10 and 20 solar panels to entirely offset their average annual electricity consumption. Obviously, electricity use, peak sun hours, and panel wattage will be different for everyone.
How long do solar panels last? ›Solar panels, also known as photovoltaic or PV panels, are made to last more than 25 years. In fact, many solar panels installed as early as the 1980s are still working at expected capacity. Not only are solar panels remarkably reliable, solar panel longevity has increased dramatically over the last 20 years.
How long can a house run on solar power alone? ›
How long can a solar battery power a house? Without running AC or electric heat, a 10 kWh battery alone can power the basic operations of a house for at least 24 hours, and longer with careful budgeting.
How much power does a 2000 square foot house use? ›Average kWh usage for a 2,000 square foot home: 1,325 kWh. Average kWh usage for a 3,000 square foot home: 1,840 kWh. Average kWh usage for a 4,000 square foot home: 2.200 kWh.
How many solar panels do I need for a 2500 square foot house? ›A 2500-square-foot home will usually need between 24 and 30 solar panels to provide 1,023 kilowatt hours of power. This is based on the average consumption of power for a home this size.
Can AC run on solar panels? ›Yes, you can power an A/C system or supplement your power supply with solar panels. The size of the unit and other factors will determine the number of panels required to power the system.
Can I run my entire house on solar power? ›Can a House Run Completely on Solar Power? The short answer: Yes, you can use solar energy to power your entire house. In fact, some people have used expansive solar panel systems to go off the grid completely, turning their homes into self-sustaining ecosystems (at least as far as energy is concerned).
How much is a solar system for a 2000 sq ft house? ›Based on national averages, solar panels cost just over $20,000 for a house with 2,000 square feet of living space. The gross cost is closer to $29,000, but claiming the federal solar tax credit worth 30% of the project cost brings the net cost down to around $20,000.
How much battery does it take to go off the grid? ›In a typical off grid cottage application, you would have a 24 or 48-volt battery bank which is somewhere in the range of 600 to 800 amp hour. They can go as high as 6,000 amp hour or more in larger systems.
How many solar panels do I need for off grid living? ›Most data suggests that a typical American home (2,000 square feet home) consumes approximately 11,000 kilowatt-hours annually. So, when we divide our total consumption by the expected output of one solar panel, we see that roughly thirteen solar panels of this size would be enough to power a home of that size.
How many solar panels do you need to live off the grid? ›| Average Monthly Electric Bill | Solar System Size | Number of Panels (Based on 200W Panels) |
|---|---|---|
| $120 | 10 kW | 52 panels |
| $240 | 20 kW | 105 panels |
| $600 | 50 kW | 255 panels |
| $1,200 | 100 kW | 510 panels |
| Square Footage | Typical System Size | # of panels (375W) |
|---|---|---|
| 3,000 | 7.98 kW | 22 |
| 3,250 | 8.64 kW | 24 |
| 3,500 | 9.31 kW | 25 |
| 3,750 | 9.97 kW | 27 |
How many solar panels do I need for a 4 000 sq ft home? ›
That average 4,000 sqft home using 1,221 kWh per month would need between 31 and 48 budget solar panels to supply all of its electricity needs.
How many solar panels do I need for a 2300 sq ft 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.
What is the solar 120% rule? ›Basically, the NEC 120% rule allows solar PV equipment to be installed in electrical boxes up to 120% of the installed electrical equipment safety label rating.
What is the 120% rule for solar system? ›The NEC, 120% rule states that solar PV systems should be installed in electrical boxes up to 120% of the busbar's label rating. For example, if the home's electrical meter rating is 175 amps, the rule allows an additional 20%, an equivalent of 35 amps from the solar system.
Can 6 solar panels power a whole house? ›How many solar panels your house needs. The number of solar panels that a home needs varies between 4 and 18 photovoltaic panel modules. To opt for more or fewer panels to make the investment of the installation profitable will depend on the annual electricity consumption for the house.
Can you get too many solar panels? ›No, there is no limit to the number of solar panels you can have. However, there may be a limit on how much power your system is allowed to generate. Some utility companies limit the amount of electricity that a grid-tied solar system can generate.
Can you use too many solar panels? ›Installing too few panels will underpower your home, while too many can result in an overpriced system. In this guide, we'll explain how many solar panels to install and provide a formula to calculate your home's panel needs.
How efficient will solar panels be in 20 years? ›While today's average panel efficiency rate hovers around 15 percent, analysts predict that by 2027, most premium solar panels will be at least 25 percent efficient. If that trend continues into the following decade, the average high-end panel in 2038 would be over 30 percent efficient.
Does hail damage solar panels? ›Usually, hail does very little damage to solar panels. However, it can chip, crack, or even break open in powerful storms. For this reason, you should take steps to protect the panels in climates where hailstorms are frequent.
Do solar panels need maintenance? ›Solar panels typically don't require much maintenance other than periodic cleaning and keeping them free from obstacles that can cast shadows over the panels. Solar panels need an unobstructed path to the sun to operate optimally.
Can you live off-grid with just solar panels? ›
Yes. Even large-sized homes can run completely off the power grid thanks to today's advanced solar technology. Large solar energy systems require many solar panels, which can be housed on a roof or even on a ground-level platform (assuming there's enough space).
How many solar panels does it take to run a clothes dryer? ›| Appliance | Capacity | Panels |
|---|---|---|
| Washing Machine | 2,500 - 3,000 W | 2 |
| Dryer | 2,500 - 3,000 W | 1 |
| Ceiling Fan | 31 W | 1 |
| Vacuum | 650 - 800 W | <1 |
It is possible to run a house on solar power alone. However, going completely off-grid requires a considerable financial and time investment. The higher your energy requirements, the more solar panels you'll need.
What uses the most electricity in a home? ›- Wet appliances. Washing machines, dishwashers and tumble dryers account for 14% of a typical energy bill, taking the top spot in our list. ...
- Cold appliances. ...
- Consumer electronics. ...
- Lighting. ...
- Cooking.
Typically, units of this size have three or even four bedrooms, plus a kitchen, living area, walk-in closets and multiple bathrooms.
How many kWh a day is normal? ›According to the United States Energy Information Administration, the average American household consumed 10,632-kilowatt hours (kWh) of electricity last year. The average kWh per month was 886, while the average kWh per day was 29.
How many kw to run a 2500 sq ft house? ›| Home Size (Sqft) | Estimated Monthly kWh Usage |
|---|---|
| 2,500 | 1,250 – 2,500 kWh |
| 3,000 | 1,500 – 3,000 kWh |
| 3,500 | 1,750 – 3,500 kWh |
| 4,000 | 2,000 – 4,000 kWh |
A 400 amp-hour 6 volt battery can provide around 2.4 kilowatt hours of power. A three-day battery bank planned to provide 90 kilowatt-hours of electricity to an average American household. The previous example battery can provide2,4 kilowatt hours, while 38 batteries would be needed.
How many kw solar do I need for 2000 sq ft house? ›| Square Footage | Electrical Usage (kWh) | PV Watts Needed to Cover 100% of kWh Usage |
|---|---|---|
| 1000 | 377 | 2200 |
| 1270 | 250 | 1500 |
| 1800 | 250 | 1500 |
| 2000 | 295 | 1700 |
| Air Conditioning Unit | Number of Solar Panels Required |
|---|---|
| Central air | 30 x 100W solar panels |
| Large window unit | 20 x 10W solar panels |
| Medium window unit | 10 x 10W solar panels |
| Small window units | 5 x 10W solar panels |
How many solar panels does it take to run a refrigerator? ›
Running an average refrigerator requires approximately three or four typical solar panels to run. Typical domestic solar panel systems are rated to produce power ranging from 1 KW to 4 KW. Different types and sizes of refrigerators require different amounts of solar power.
How much does a solar air conditioner cost? ›| Solar AC Panel | Power of the Panel | Selling Price |
|---|---|---|
| 1 Ton Solar Air Conditioner | 1500 Watt | Rs. 99,000 Approx. |
| 1.5 Ton Solar Air Conditioner | 2500 Watt | Rs. 1,39,000 Approx. |
Heating your home with an active solar energy system can significantly reduce your fuel bills in the winter. A solar heating system will also reduce the amount of air pollution and greenhouse gases that result from your use of fossil fuels for heating or generating the electricity.
Do solar panels work on cloudy days? ›Photovoltaic panels can use direct or indirect sunlight to generate power, though they are most effective in direct sunlight. Solar panels will still work even when the light is reflected or partially blocked by clouds. Rain actually helps to keep your panels operating efficiently by washing away any dust or dirt.
Can solar panels replace generators? ›The answer is simple. Solar power will not serve as a backup generator. Solar energy will go out just like other forms of energy do during a severe storm. Keep in mind, however, that this does not make solar energy any less of a valuable investment for your home.
Will solar panels get cheaper in 2023? ›Solar costs are very likely to decrease in 2023, making rooftop renewables affordable for more homeowners. In November 2022, the National Renewable Energy Laboratory (NREL) published its analysis of the cost of solar and energy storage (battery) system installations for the first quarter of 2022.
How do I calculate how many solar panels I need? ›You can calculate how many solar panels you need by multiplying your household's hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel's wattage. Use a low-wattage (150 W) and high-wattage (370 W) example to establish a range (ex: 17-42 panels to generate 11,000 kWh/year).
How much does a grid tied solar system cost? ›How much does a grid-tied solar system cost? The average cost of a typical grid-tied solar system is between $12,600 and $14,000 net of the federal solar tax credit. Most systems cost between $2.75 and $3.35, with a national average price of around $3.00 per watt as of 2023.
How many solar panels do I need for a 1200 square foot house? ›On average, a home that is 1200 square feet will need somewhere between 12 and 15 solar panels to provide enough electricity for the home. Of course, this could fluctuate based on how much sunlight is in the area as well as the amount of energy consumption for the home.
How many solar panels do I need for 2000 kWh per month? ›To generate 2000 kWh per month you will require 37 numbers of 400-watt solar panels if your city has 4.5-5 hours of average sunshine per day over a year. Moreover, if your city has 3.5-4 hours of average sunshine per day over a year then you will require 60 numbers of 400-watt solar panels.
How many solar panels do I need for 1000 kWh per day? ›
It gives us 20.83, or 21 panels when rounded up. This estimate indicates that we need 21 panels rated at 400 watts to gather enough energy to supply a home with 1000 kWh. That said, you may want to size up a bit more to account for rainy months, power lost to inverters, and other factors.
How many kw do I need to run a 2000 square foot house? ›Average kWh usage for a 2,000 square foot home: 1,325 kWh. Average kWh usage for a 3,000 square foot home: 1,840 kWh. Average kWh usage for a 4,000 square foot home: 2.200 kWh.
How many kw does it take to run a house? ›How Many Kilowatts Does It Take to Power a House? With the average American home consuming 900 kWh a month or 30 kWh a day, that brings the total yearly usage to around 10,800 kWh. This means that most solar energy systems will need to be large enough to produce this many kWh's in a given year.
Can 10kW power a house? ›Is a 10kW solar system enough to power a house? Yes, depending on where you live, a 10kW solar system would be enough to power the average home of a family of four and enough to power the average 2,000-square-foot home in the United States.
What size solar system do I need for kWh per month? ›| System size | Estimated monthly energy production | Number of panels* |
|---|---|---|
| 8 kW | 960 - 1,200 kWh | 20 |
| 10 kW | 1,200 - 1,500 kWh | 25 |
| 12 kW | 1,440 - 1,800 kWh | 30 |
| 14 kW | 1,680 - 2,100 kWh | 35 |
If you have one 250-watt panel receiving four hours of sun, then you will get 1,000 watts or one kWh per day from that panel. If you have four panels, you will get 4 kWh per day. If you have 33 panels, assuming a 30-day month, you will get 1,000 kWh per month.
What is a good kWh per day for solar panels? ›Multiply 5 hours of sunlight x 290 watts from a solar panel = 1,450 watts or roughly 1.5 kilowatt hours per day. That's about 500-550 kilowatt hours of energy per year from each panel on your roof.
How many solar panels do I need for 1kwh? ›kWh stands for kilowatt-hour. 1 unit of electricity implies 1 kW generated/ utilized in an hour. You need to install at least 3-4 solar panels based on watt peak in an array for the 1 kW solar system.
Is 50 kWh a day a lot? ›This too varies depending on the size of the solar array you've installed on your home, where you live, the weather, and many other factors. But since most homes are comparable enough in size and we can't control the weather, 50 kWh per day is a good number to use, though maybe a bit on the high end for some homes.