The first question homeowners ask when going solar is “How many solar panels do I need to power my home?”
The goal of any solar project should be 100% electricity offset and maximum savings – not necessarily cramming as many panels on the roof as possible. Therefore, the number of panels required to power a house depends on three main factors:
energy used
Sun exposure
Solar panel power rating
Solar panels come in a variety of sizes, and knowing which size you should buy is crucial to efficiently powering your home during a power outage. In this guide curated just for you, we dive into everything you need to know about choosing the right solar panel size for your home.
We’ll show you how to manually calculate the number of panels you need to power your home. Once you estimate the number of solar panels, you’re one step closer to figuring out how much solar power will cost for your home and how much you can save on your energy bill.
What are house solar panels
A house solar panel is a device that converts solar radiation into electrical energy by absorbing sunlight. It uses solar panels to capture solar energy and store it in a solar generator. Solar panels on the roof absorb the sun’s energy and convert it into electricity. Using solar panels on your roof to absorb the sun’s energy and convert it into electrical current, a solar generator converts the energy from the sun into direct current (DC) that is stored in a battery, which is then used to charge or operate appliances. However, this DC power cannot directly power devices in your home.
To solve this problem, another important component in a solar generator, called a solar inverter, converts DC power into alternating current (AC). The alternating current can then be used to power necessary equipment.
For homes, solar energy can serve as a backup solution to keep buildings powered during power outages. Power outages are becoming more frequent and show no signs of slowing down. In the United States alone, the average number of weather-related power outages per year is expected to increase by 78% between 2011 and 2021.
With the alarming increase in frequency of power outages due to weather-related events, it is imperative to find a sustainable solution to obtain power during outages. While there are several other options, such as fuel-fired generators, none are as sustainable and environmentally friendly for the home as a solar generator.
| Appliance | Power Consumption (Watts) |
| Air Conditioner (Room) | 1000 |
| Air Conditioner (Central) | 2000-5000 |
| Ceiling Fan | 65-175 |
| Clothes Dryer (Electric) | 3000 |
| Clothes Dryer (Gas) | 1800 |
| Clothes Washer | 350-500 |
| Coffee Maker | 900-1200 |
| Deep Freezer | 500 |
| Desktop Computer | 100-450 |
| Dishwasher | 1200-2400 |
| Electric Blanket | 60-200 |
| Electric Kettle | 1200 |
| Electric Oven | 2150 |
| Electric Stove (8″ Element) | 2100 |
| Flat Screen Television | 120 |
| Furnace Fans | 750 |
| Hair Dryer | 1200-1875 |
| Heater (Portable) | 750-1500 |
| Iron | 1000-1800 |
| Laptop | 50 |
| Microwave Oven | 750-1100 |
| Refrigerator / Freezer | 700 |
| Toaster | 850 |
How many solar panels do you need to power your house?
While each household’s situation is different, U.S. households typically require 10 to 20 solar panels to fully offset their average annual electricity usage.
The goal of most solar projects is to offset 100% of your electricity bill, so your solar system is sized for your average electricity usage. You can use the following basic equation to estimate the number of solar panels needed to power your home:
Solar panel wattage x peak sunshine hours x number of panels = daily electricity usage
Obviously, everyone’s electricity usage, peak sunlight hours, and panel wattage will vary. Since you’re not here to do algebra, we’ll cover how to calculate each variable and run a sample scenario based on national averages.
First, find out how many kilowatt hours your home uses
According to the US Energy Information Administration (EIA), households in 2021 was 10,632 kilowatt hours (kWh). This is equal to:
886 kWh per month
Approximately 30 kWh per day
It’s worth noting that this usage varies from state to state. For example, the average daily electricity usage in Hawaii is about 18 kWh, and the average daily usage in Louisiana is 40 kWh, which is quite a difference. But we will use the national average of 30 kWh per day as an example figure.
The easiest way to find your daily electricity usage is to look up some recent utility bills. Your bill should show your usage for 30 days (or whatever your payment term is), which you can use to get an idea of your daily electricity usage. Just take the total usage for the period and divide it by the number of days.
Choose the power rating of your solar panel
The final variable is how much power each solar panel can produce during each peak sunlight hour. This is called the power rating and is measured in watts.
Solar panels are available in power ratings ranging from 250W to 450W. According to sales data from sungoldsolar.com, 400W is by far the most popular power rating and offers a good balance between output and price per watt (PPW).
If you have limited roof space, you may consider a higher rating to use fewer panels. If you want to spend less per panel, you might consider a lower wattage. Everyone has different goals, and you should feel free to choose the panel that best suits your needs.
For the purpose of the example scenario, we will use 400W solar panels.
Calculate how many solar panels a house needs
Now that we have three variables, we can calculate how many solar panels we need to power our house.
Daily electricity usage: 30 kwh solar system (30,000 watt hours)
Average peak sunshine hours: 4.5 hours per day
Average panel wattage: 400w solar module
To solve for the number of solar panels, we can rewrite the above equation as follows:
Daily electricity consumption/peak sunshine hours/panel wattage = number of solar panels
Now let’s insert an example plot:
30,000 watt hours/4.5 peak sun hours/400W = 16.66 panels
If we round up, it would take 17 solar panels to power the average American home and achieve the goal of 100% electricity offsetting.
Since we’re talking about national averages, the national average electricity price in the United States in May 2023 was 16.5 cents per kilowatt hour.
Frequently asked questions
How many solar panels does a house need to power?
Based on average electricity usage and peak sunlight hours, a home would require approximately 17,400 watts of solar panels to power its home. However, this number will vary between 13 and 19, depending on the amount of sunlight the panels receive and the household’s electricity usage.
Use the formula below to estimate the number of solar panels needed to power your home.
Daily electricity consumption/peak sunshine hours/panel wattage = number of solar panels
Can I run my house on solar energy only?
Absolutely. By pairing solar panels with a solar generator, it’s possible to run your home entirely on the sun’s energy. In many areas, this is cheaper than paying your electricity bill through your local utility company.
If you don’t have a solar generator, you can still eliminate your electricity bill by using solar panels to offset grid usage through net metering. When solar generation stops, you will still use grid power, but you will only pay for the solar equipment.
Is 10 kilowatts enough?
Yes, in many cases a 10 kW solar system is enough to power a house. The average U.S. household uses approximately 30 kWh of electricity per day, which would require a solar system ranging from 5 kW to 8.5 kW (depending on sunlight exposure) to 100% offset this.
How much does a house solar generator cost?
The cost of a solar generator varies based on size, manufacturer, model, capacity, type and even location.
How long can solar panels power a refrigerator?
This depends on the capacity of the solar panels and solar generator, the wattage of the refrigerator and the energy efficiency. For example, a solar generator with a 1000Wh battery capacity can power a 100W refrigerator for up to 10 hours.
Can I use portable solar panels for home?
Advantages and Disadvantages of Using Portable Solar Panels for Home
Whether portable solar panels are right for your home depends on your clean energy goals and your specific energy needs. While portable solar panels are a great way to supplement your electricity usage or provide power in remote areas, they may not be enough to power your entire home.
Can solar panels power a house?
Convert sunlight into direct current (DC) electricity through solar cells. These panels are composed of multiple solar cells made of semiconductor materials such as silicon, which absorb sunlight and generate an electric charge.
In order to use solar panels to power a house, the direct current generated by the panels needs to be converted into alternating current (AC), which is the standard form of electricity used in homes. This conversion is accomplished through an inverter, which converts DC power into AC power suitable for powering household appliances and electrical systems.
The size and number of solar panels needed to power a home depends on a variety of factors, including the home’s energy consumption, available sunlight, and local regulations or incentives. Generally speaking, larger solar panel systems will produce more electricity and have the potential to provide most or even all of a home’s energy needs.
It’s worth noting that solar panels generate electricity when exposed to sunlight. Therefore, their ability to power a home is affected by factors such as the location, orientation and tilt angle of the solar panels. Areas with sufficient sunshine, such as deserts or areas near the equator, are generally more conducive to solar power generation.
Additionally, a home’s available roof space and structural considerations also play an important role in determining the capacity of a solar panel system. The roof should have sufficient unobstructed space to accommodate the panels and should be oriented and sloped to optimize sunlight exposure throughout the day.
To ensure reliable power supply, solar panels can be combined with energy storage systems such as batteries. These batteries can store excess energy generated during the day and be used when there is insufficient sunlight or at night when the solar panels are not producing electricity. With storage systems, homeowners can further reduce their reliance on the grid and have access to power even during outages.
Advances in solar panel technology, including greater efficiency and increased durability, make solar an increasingly attractive option for homeowners. Additionally, many countries offer various government incentives and rebates to encourage the adoption of solar systems.
While solar panels have the potential to power a home, it’s important to consider the upfront cost of installation. Initial investment may vary depending on factors such as system size, material quality and installation complexity. However, it’s worth noting that over time, the savings on electricity bills and the potential to sell excess power back to the grid can offset the initial investment, making solar power a cost-effective option in the long run.
To sum up, solar panels have the ability to power a house by converting sunlight into electricity through photovoltaic technology. The size and capacity of a solar panel system depends on factors such as energy consumption, available sunlight, and structural considerations. When combined with energy storage systems, solar panels provide homeowners with a reliable source of renewable electricity while reducing reliance on the grid. As technology advances and costs fall, solar energy is becoming an increasingly attractive and sustainable option for households around the world.
