House shown with solar panels during the day.

How Many Solar Panels Do You Need To Power A House?

Apr 6, 2022

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Installing solar panels on your home offers myriad benefits, including increased energy efficiency, cost savings and helping the environment. As you plan your solar installation, you may also be wondering how many solar panels it takes to power a house. In this article, we will take a look at how you can determine the best number of solar panels for your installation.

How Much Energy Does An Average Home Use?

According to the U.S. Energy Administration, the average home’s energy consumption in the United States is 10,715 kilowatt-hours (kWh), an average of about 893 kWh per month. Naturally, the actual energy use will vary quite a bit depending on where a homeowner lives. Where you live also has a big effect on how much energy you can get from a solar panel installation. The average cost that you pay for electricity also varies by location, which can affect how long it takes to pay back your solar installation.

What Are Solar Panels?

Solar panel systems are devices used to collect sunlight and turn it into usable electricity. Most solar panels use photovoltaic technology to collect solar energy from the sun. Solar power is typically collected as direct current (DC), so most homeowners will need an inverter to convert that solar energy into alternating current (AC) which powers most homes.

Can Solar Panels Power A Whole House?

Solar panels can power a whole house, but it is dependent on several factors. These include the average daily sunlight for your area, the climate and how often the appliances in your home are used.

  • Sunlight: Solar panels will likely need at least 5 hours of direct sunlight per day to run an entire house.
  • Climate: Solar panels don't produce electricity during the night or as much electricity on cloudy days; therefore, batteries help when the weather isn’t ideal.
  • Appliance size and usage: The size of each appliance in your home and how often they’re used will help determine whether solar panels can power your whole house.

How Many Solar Panels To Power A House: Important Factors

As mentioned above, the average home in the United States uses 10,715 kilowatt-hours (kWh) every year, based on the U.S. Energy Administration's data. Based on this number, homeowners should use between 20 and 40 solar panels to power their houses. And while that’s a large range, the size of your solar system is dependent on a number of individual factors:

Size Of The House

Larger homes typically consume more electricity and need more solar panels. This is primarily due to a larger home being more expensive to heat or cool since there is more square footage.

Direct Sunlight

Location of your home matters, as does the amount of sunshine your property receives. More sunshine for your solar panels means they will produce more electricity more efficiently for your home. Shading on your roof from trees and other obstructions can also impact panel energy production.

Electricity Usage

It's important that homeowners understand their annual electricity usage when determining the number of solar panels needed to power a house. This amount includes all sources of electricity, like small and large appliances, air conditioning units, lights, water heaters, etc. Electricity usage is typically measured in kilowatt-hours. Remember that your electricity consumption may increase over time, which can require adding solar panels to your existing system.

Number Of Household Occupants

Households with more members typically use a higher amount of electricity, since there are more electronic devices, more hot showers and more lights used. That means you may need more solar panels to increase energy production.

Solar Panel Wattage

Solar panel wattage is the amount of electricity emitted from the panel. The higher the wattage of a particular solar panel, the more energy it produces but also the more it usually costs. The average solar panel wattage ranges between 250 to 400 watts of power per panel.

How To Calculate How Many Solar Panels Are Needed To Power Your Home

To figure out how many solar panels are needed, you'll want to first look at your utility bills to determine the total amount of electricity (measured in kWh) you use in a year.

You'll also want to know the wattage and productivity of the solar panels you're looking to buy. Dividing those numbers should get you the number of panels you'll need for your solar installation.

As an example:

  • Say your home uses 10,000 kWh of electricity per year.
  • You are looking at 300-watt solar panels with a productivity number of 1.4.
  • Dividing 10,000 / 300 / 1.4 gives around 24 solar panels needed to power your home.

Types Of Solar Panel Systems To Power A House

There are a few different types of solar panel systems that can be used to power a house. These can be used with either a roof solar system or ground mounted solar panels:

Grid-Tied

A grid-tied system is a solar panel system that is directly tied into your local utility's electrical grid. This allows you to use power from the grid when your solar panels are not producing energy. It also can allow you to take advantage of net metering to sell any excess power you produce back to your utility.

Grid-Tied With Battery Backup

A grid-tied battery backup system is similar to a grid-tied system but also includes a battery backup. If the sun is shining and you are producing solar energy, you use that first and then charge your batteries. Then, when the sun is no longer shining, you can use the energy from your batteries first before pulling power from the electrical grid.

Off-Grid

An off-grid system is one that is completely disconnected from a larger electrical grid. This is common in very rural or remote areas where connecting to an electrical grid may be cost-prohibitive. In an off-grid system, you are solely responsible for your electrical needs. So if the sun is not shining and you don't have sufficient battery storage, you won't be able to use electricity.

Why Should You Use Solar Energy?

There are several benefits for homeowners to use solar energy in their green smart homes. Here are a few of the top reasons:

A Source Of Renewable Energy

Solar energy is a renewable energy source, because it comes from the sun and does not rely on fossil fuels. Any amount of energy that you produce from the sun is one less kilowatt that needs to be produced using nonrenewable sources like coal, oil or natural gas.

Saves Money

Solar energy can help significantly decrease a homeowner’s electric bill because of the power they’re generating and using. Each kilowatt-hour that you produce from your own solar energy installation is one that you don't need to buy from your local electric provider.

Low Maintenance

Solar panels have very few moving parts, and as such, require little maintenance. Different solar panels have different lengths of warranty or shelf-life, so you'll want to check the specifications of your particular panels. It is common for solar panels to last for up to 20 – 30 years as long as you take good care of them.

Efficiently Generates Energy

Solar panels are more efficient at generating energy; therefore, less energy is wasted than with other methods. As you compare different solar panels, make sure to check the efficiency of the panel so you can accurately calculate the energy usage that each panel will provide.

Increases Property Value

A home with solar panels could increase see an increase in property value, especially if the solar installation is completely paid for. When buyers are looking at your home, knowing that they may be able to save hundreds of dollars per month on their electrical expenses might make them willing to pay more than they would for a comparable house without solar panels.

The Bottom Line

There are many compelling reasons to install solar panels on your home. Converting more of your electricity generation to renewable sources will help the climate and save you money. Before installing solar panels, make sure you know how much electricity you use and how much direct sunlight your area gets. That will help you calculate how many solar panels you'll need to power your house.

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