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How Many Solar Panels Do I Need

How Many Solar Panels Do I Need

When it comes to powering your home the natural way, solar power is the winning choice.

Having solar panels installed on your rooftop or using some other form of solar is so common these days that most streets will have at least one neighbor using the sun’s natural energy in their home.

If you’re yet to join the trend, you’re probably wondering where to even get started and much you’d need to power up your humble home.

How many solar panels do you need for your house then?

There are many factors to be considered when installing solar including your average energy expenditure, size of your dwelling, how much sunlight your house gets, and the type of solar panels and cells you use.

By determining all of these, a professional solar installer can determine how many you need to reach your goals.

Solar power is nothing new, but in the United States, it’s a trend that’s rapidly growing. An estimated 2 million solar setups have been installed, with that number predicted to reach 3 million in 2021.

With that in mind, there’s no better time to get on board with this natural energy source and find out exactly what your home needs to harness the power of solar.


What Are the Best States in the US For Using Solar Power?

What Are The Best States In The US For Using Solar Power?

With the number of homes using solar power growing in the US, it appears that some states have been more welcoming to the green energy source than others.

Although there are now millions of homes across the country using it, some states are using it more, and this can be due to several factors including state tax incentives, cost, availability, and interest in renewable energy.

California is the current leading state in terms of solar energy production with systems capable of creating more than 21,000 megawatts of electricity which is enough to power up over 5 million homes.

In second place is North Carolina, with a figure that’s a lot less, as this state produces enough energy to power just 486,339 homes.

The difference in solar power generated likely has to do with the local interest in using solar power and green technology, as well as the naturally sunny conditions.

Their interest is something that will hopefully spread throughout the country in the years to come.

If more homes and businesses were able to make the switch to solar, we’d see a dramatic decrease in our carbon emissions, but the first step is establishing how to make it work on your very own rooftop.

How Many Solar Panels Does the Average House Need?

How Many Solar Panels Does The Average House Need?

Calculating solar use based on the average American household is hard to do, with so many different climates, family sizes, energy consumption, and types of dwelling found in this country.

For this reason, we’ll look at the average small, three-bedroom home from a temperate climate and compare it with a larger home in the south that uses a lot of cooling energy due to higher temperatures.

The small home uses around 200kWh per month and the large home around 2,000 kWh per month, so you can see there’s quite a difference.

In between that, we find the average American home using around 900kWh a month, which equates to around 30kWh a day or 1.25kWh an hour.

An average homeowner would need between 25 to 35 solar panels to offset their entire energy use. This is assuming 250-watt solar panels were used, and they had an average amount of sun exposure.

However, most people will only want to offset some of their energy bills, so this full amount might not be required. Again, it depends on your circumstances and what you hope to gain from going solar to get an accurate figure.

How Many Solar Panels will I Need?

Every household is unique and there’s a good chance you’ll require something a little different compared to the average American home.

To determine how many solar panels you need specifically, you need to have some clear goals in place and have a good idea of what your current situation looks like.

When thinking about your goal for solar, ask yourself what exactly it is you’re trying to achieve. Do you want to put solar in to increase the value of your home?

Do you want to save as much money as possible from your energy bills? Do you want to do your part for the environment and reduce your carbon footprint? Do you want to totally go off the grid and only rely on solar power to run your home?

The answer to these questions will give you a good indication of how many solar panels you need.

The average person’s goals are to do their part for the environment while saving themselves money, so with that in mind, we can then move onto the important questions to determine where to go next.

The Questions to Answer to Calculate Your Solar Needs

The Questions To Answer To Calculate Your Solar Needs

Before you call the professionals and have a solar installer out to your house, you can get an idea of what you’re going to require to use this type of energy.

Consider these questions to see how many you’ll need based on your current usage, home setup, and future goals, to get a rough estimation of the type of solar setup you require.

How Many Watts of Power Do You Use?

To determine how many solar panels you need, you need to know how much energy you use. If you’re looking at replacing a large portion of your electricity use with solar, you have to get an idea of your average electricity bill.

Assess your electricity bill by finding the kilowatt-hours used for that period, or a meter reading that lets you calculate the figure for yourself based on the bill from the previous period.

Take this number and divide it by 30 to get the average daily use, and then divide it again by 24 to establish the hourly amount. The answer will be how much power you use at any given time in your home and is known as the kilowatt-hours or kWh.

How Much Sunlight Do You Get?

Knowing how much sun hits your house, and more importantly, the roof is a crucial part of the solar installation process.

This is something a professional installer can help with but it’s good to get an understanding for yourself before calling them out.

Each house has what’s referred to as their ‘peak sunlight hours’ and this is the amount of time you have full exposure to the sun.

Some parts of the country like Phoenix will have more sunlight than others, like Seattle, so in this case, the Seattle homeowner would need to place more panels on their roof to get the same amount of solar energy.

If you don’t want to get a professional solar installer out to your property, you can still get a good estimate of your sunlight hours.

Websites like the Renewable Resource Data Center gives these kinds of details for major cities so you can find one that’s closest to you.

How Much Solar Power Do I Need?

The most accurate way to determine how much solar you’ll need is by looking at your energy use and getting an idea of your average everyday consumption.

Every household runs differently and some use a lot of power on things like air conditioning and heating, whereas others are more conservative and only use the basics.

Now that you have your kilowatt-hours, you’ll be able to calculate your solar panel requirements. With the hourly figure you have, you’ll want to multiply this by the peak hours of sunlight your home gets.

In short, this can be determined by its exposure to the sun and also where you’ll be able to lay panels once they’re installed.

Finally, find the amounts of power that a conservative solar panel and a high powered one create to get an idea of what they can do. Low wattage panels are around 150W and high power 370W, so they can differ quite a lot.

With the figure you get from hourly energy use multiplied by peak sunlight hours, you can then divide it by the wattage of the panel to estimate how many panels you need.

Factors That Affect Solar Power Efficiency

Factors That Affect Solar Power Efficiency

The other important part of the equation when calculating how many solar panels a house needs is the efficiency of the panels themselves.

By understanding how powerful and effective a panel is, we get a better idea of its energy output, so consider these things when assessing how many panels you’ll need.

Inverter Efficiency

The inverter is the piece of equipment that turns the direct current (DC) into alternative current (AC). In simple terms, this is what turns the energy from the sun and solar panels into energy that can be used for your home’s electricity.

With current inverter technology, this is still not at 100 percent, so depending on the unit you use, you can expect to lose as much as 8 percent of what your solar panels produce.

Life of Panels

Over the years, the efficiency of solar panels tends to degrade so the longer you’ve had it the less power it will provide.

The general lifespan on quality solar panels is more than 25 years and most manufacturers will guarantee their panels to be working at optimum levels for this time.

Check the warranty of panels before you buy them to ensure they have this guarantee, and be prepared to replace them when they’re no longer efficient.


Where you live can play an important role in how your solar panels perform, and especially if you live in very hot climates.

Those living in hot regions like Phoenix or San Antonio may find their solar panels don’t emit as much energy because they get overheated which leads to poor airflow.

A professional installer will try to limit this as much as possible and will be able to show you where to place them to keep airflow at its best.

Choosing Solar Panel Materials and Sizes

Choosing Solar Panel Materials And Sizes

The type of solar panel is important in determining its output and provided all of the factors are right at home, this is the decision that will have the most impact on the energy source.

There are three main types of solar panels to choose from, each slightly different from the other, and you’ll need to consider them all before you make the switch to solar.


The most common type of solar panels and one you see on most rooftops, often with a blue or black color. These solar cells are made from larger silicon crystals and are known for their high efficiency.

The corners of the cells are curved which can be an issue when piecing them together to form a solar panel as it loses them some space.


These cells are made from pouring silicon into models so they’re not as pure as mono which has been cut direct from larger crystals.

As a result, they’re known as slightly less efficient. However, because they’re square-shaped, they waste less space when forming a panel. Poly solar panels are slightly cheaper but almost as efficient so a smart choice for homeowners.

Thin Film

The cheapest option of all, thin film is made by spraying silicone onto a surface and removing the thin film. When put together, the panels are quite heavy and not generally used for homes, but rather individual smaller products.

Because of their cheap price, it’s not surprising that they’re also less efficient, but still, a smart way to use the sun’s natural energy.

The size of the panels will also affect their efficiency but it depends on your usable roof area as to what will work best. With a larger area, you’ll be able to buy larger panels that are usually cheaper, to achieve your output.

For those with unusually shaped roofs or smaller spaces, you may need to use smaller panels but with higher efficiency to make up for it, which could be more expensive.

Smart Energy from the Sun

Smart Energy From The Sun

Solar energy is one of the most well-known forms of green energy around and something that has been used for decades.

As the manufacturers of these solar cells and panels come up with new ways to make them more efficient and affordable for the everyday homeowner, it’s something that more homes will hopefully be happy to embrace.

As you can see, there are so many factors to consider before investing in solar for the home, and it’s not just as simple as covering your entire roof with panels.

While a dedicated installer can walk you through the basics and show you what would suit your home, it’s easy enough to get an idea of this for yourself with measurements.

A solar setup can be as unique as your home, whether you want to go completely off the grid or just supplement a little bit of your electricity use with natural resources.

Whatever you do, you’ll be making a positive impact on the earth and relying on the heat of the sun to power up your home, which is the best source of energy there is.

Related Questions

Solar panels have many capabilities, and not just for powering the home. Some people use solar energy to run their RVs, charge up battery-operated devices, or work just their garden lighting.

If you’re new to solar energy, we’ve got the answers to some commonly asked questions that can give you more insight into how they operate.

How Long Does it Take to Charge a Solar Battery Bank?

A 25,000mAh solar power bank will take around 50 hours to charge fully. Provided it’s kept in direct sunlight and no obstructions are surrounding it, you should be able to leave it in the one spot until it’s charged and then use it as you need.

What Will a 300-Watt Solar Panel Run?

300-Watt solar panels are popular choices for RVs and camping because they’re able to power up several household appliances at a time.

With a full battery, this size solar panel will run a, LED light, music player, and television for a couple of hours, or single appliances for five or more hours.

Can a Solar Panel Be Repaired?

If your solar panel is damaged by strong weather or other causes, you may be able to have them repaired.

In most cases, it’s cheaper and more effective to replace the panel altogether, but this is something that the installer should decide to keep efficiency at its best. Faulty panels are covered by a warranty which extends for 25 years in most cases.

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