Can a House Run on Solar Power Alone from Roof Solar Panels?

Solar is on track to becoming a major energy source. In 2021, a solar system was installed every 60 seconds, and yet solar makes up less than 3% of U.S electricity generation.

A primary concern for homeowners about solar is how much energy it produces. Can solar panels power a house for instance? These two questions are the main subjects of this article.

You cannot in fact power a home with only solar panels. One needs batteries as well. But just how many solar panels does it take and what would the configuration look like?

If you have ever wondered how many batteries are needed in a solar system you are about to find out.

How Many Solar Panels Does It Take to Run a House?

You need between 15 to 20 solar panels to power the average American home. The precise number is a factor of your energy consumption, solar irradiance, and the solar panels themselves. Lower consumption, higher irradiance, and bigger solar panels will reduce the number of solar panels you would need.

The first thing you would need to do to work out how many solar panels you need is to work out your energy consumption. Then you would have to find out how much sunshine your home receives.

How Much Energy Do You Need?

You establish this by finding out how much energy you currently use. The simple way to do this is to look at your energy bills over 12 months. Once you have your monthly average you can then divide that by 30 days to get your daily average. In the U.S the average daily use is about 30 kWh. (Source)

Bear in mind this is an average number. Your actual consumption may be more or less depending on the size of your home in square feet and the size of your household in terms of how many people share the same roof. As a rule, the larger the home or household, the greater the consumption.

Once you have worked out how much energy you use the next step is to work out how much sunlight your home receives.

Factors Impacting How Much Energy Solar Panels Are Capturing from Sunlight

Solar irradiance

Solar irradiance is a measure of how much sunlight an area receives. The more sunlight a solar panel receives the more solar energy it can produce. Some states in the U.S have a higher solar irradiance than others. Arizona is much sunnier than Alaska, receiving 7 to 8 hours of peak sun hours compared to 2 to 3 in Alaska. (Source)

Solar panel type

Once you have worked out how much energy you need and how much available sunlight there is to produce energy from you need to pick the right solar panels.

Solar panels differ in how efficiently they convert sunlight into electrical current. Monocrystalline solar panels are the most efficient followed closely by polycrystalline. Thin-film solar panels are the least efficient which is why they have a smaller market share.

Solar panels also differ in size and watt rating. There are solar panels with 60 solar cells and there are panels with 72 solar cells. Watt rating ranges from 100 watts right up to 450 watts. Naturally, if you get solar panels with more solar cells and a higher watt rating, you will buy fewer solar panels.

Do Solar Panels Power Your House or The Grid?

Solar panels can be used to power both your house and the grid. A solar system can be configured to feed surplus electricity to the grid once your personal needs are covered. You can sell your excess electricity back to the grid. This is called net metering.

With net metering, any energy generated by your solar panels is fed into the grid. This energy is bought as credit by your power company. You do not receive money in exchange for it but credits on your energy bill instead.

Also, check out “Does Solar Increase Home /Property Value? (What You Need To Know! )“

Can You Use Solar and Electricity Together?

Solar can be used in conjunction with electricity in a grid-tied or hybrid solar system. There are several ways in which this can be configured. The main advantage of it is that it reduces your electric bill while not making you completely dependent on solar which can be erratic.

One of the most common ways to set this type of design up is to use electricity for your major appliances like washing machines and air conditioners and then use solar energy to power smaller loads like your television and lights.

Another simpler configuration is to have your home running on solar during the day and then switch to electricity at night.

On a side note, check out our post “Can Solar Panels Run an Air Conditioner? All You Need To Know!“

Can You Disconnect Your Solar from The Grid?

Solar does not have to be connected to the grid. You can run a solar system in an off-grid design. With this configuration, you are not connected to the grid and all your power is supplied by your solar panels.

An off-grid solar system is a very attractive system design for several reasons. For one you are completely independent of the grid which means you do not have to pay for electricity. You never have to worry about the grid going down and you are producing energy from a sustainable resource.

On the downside, off-grid systems are much more expensive than grid-tied systems. This is because they always include batteries in their design whereas batteries are optional in grid-tie systems. Batteries are easily the most expensive part of a solar system and it is this additional equipment that drives up the cost of an off-grid solar system.

How Many Solar Batteries Are Needed to Power a House?

One battery can power a house. The more batteries you have, the greater the capacity of your battery bank. The number of batteries you would use to power your house would depend on what type of battery you used and the purpose for which you need batteries.

Lithium batteries provide the most energy. The other option is lead-acid batteries but they do not provide as much energy. Depending on whether you were looking to use your batteries in a grid-tie or an off-grid system you would need 1-3 or 8-12 batteries.