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How many solar panels do I need

How Many Solar Panels Do I Need? Calculator with 5 Factors

If you’re thinking about buying solar panels for your house, a big factor to consider is how many solar panels do I need? The number of panels primarily accounts for the solar installation cost, both when calculating the materials and the labor to install them.

The last thing you want to do is have too few solar panels, so you aren’t getting sufficient payback for your investment. Nor do you want too many solar panels; an over-engineered system is an unnecessary expense for less ROI. As Goldilocks might say, you don’t want a solar panel system that is too big or too small, you want the number of solar panels that are just right.

So how do you calculate how many solar panels do I need?

Determining the number of solar panels you need depends mostly on these five factors, including your energy consumption now and in the future, the location of your house, the efficiency of the solar panels, the size of your roof, and the amount of sunlight your home receives.

Here’s a general guideline to help you estimate how many solar panels your house needs. If you prefer to have a solar power calculator do the thinking and math for you, try ours for an instant estimate.

Ultimately, speaking to a professional will provide you with the most accurate answer. So if you live in Illinois, Wisconsin, or Michigan there’s no better than us, TruHome Pros!


5 Factors To Consider When Calculating How Many Solar Panels Do I Need

1. Determine Your Energy Consumption

Look at your electricity bills to determine your average yearly kilowatt-hours (kWh) energy consumption. Because electricity consumption varies according to the seasons, annual energy usage better estimates how many solar panels you need. The more appliances you run, the bigger your family, the higher your annual kilowatt consumption.

A refrigerator requires one solar panel, central air conditioning needs at least two, and an electric car needs at least five.

Another way of calculating your energy consumption is by home square footage. Generally speaking, a 2,000-square-foot home has an estimated annual electricity consumption of about 9,400 kWh, which requires 16-18 solar panels. A 3,000-square-foot home uses more than 14,000 kWh, requiring 24-27 solar panels.

For comparison purposes, consider that according to the U.S. Energy Information Administration, the average American household electricity consumption is 10,632 kWh of electricity per year or an average of 886 kWh per month. That works to anywhere between 15 to 19 solar panels needed to generate reliable electricity.

2. How Much Sunlight Do You Get?

Homes located where there is more sunlight need fewer solar panels to generate the same amount of energy as homes in areas with less sunlight. In the Midwest, you can expect about four peak hours of sunlight daily.

However, other factors play into how much direct and indirect sunlight your home receives, including which direction the house roof faces and the presence of large trees that shade the roof.

3. How Big is Your Roof?

High-efficiency panels generate more electricity in the same amount of space. If your home is small or has an unusual roof, you’ll probably want to consider smaller but high-efficiency solar panels to gain optimal output. In this case, the available roof square footage restricts the number of solar panels.

Those with larger roofs can sacrifice some efficiency with larger solar panels to achieve the same output. Also, chimneys and skylights limit how many solar panels you can place on even large roofs.

4. What is the Wattage of the Solar Panels?

Solar panel wattage measures how much electricity the panel can produce. Residential solar panels produce anywhere from 300 to 450 watts. The higher the wattage, the fewer solar panels you will need.

We, at TruHome Pros, only use the best tier one solar panels in the industry.

5. How Much Energy Does The Solar Panel Produce?

The average energy produced by a single solar panel is about 2 kWh daily or 60 kWh monthly. If you are looking to power your entire energy bill and you use an average of about 900 kWh monthly, for example, then you will need a minimum of 15 solar panels for your home.


Solar Panel Calculations

There are formulas for calculating the number of solar panels need for your house. One commonly used calculation involves estimated energy output over time (in kWh) compared to solar panel wattage, which is called a production ratio. The production ratio shows you how powerful the solar energy system you install on your home must be in order to see a sizable reduction in your monthly electric bill.

Calculating a production ratio is fairly complicated and is best left to solar panel professionals. However, let’s use a simplified example to explain how many solar panels do I need: a 10-kilowatt system that produces 15 kWh a year has a production ratio of 15 divided by 10, or 1.5.

Now, let’s say you selected panels that produce 300 watts. You also need the solar system to generate 900 kWh to cover your average monthly energy consumption. Divide that number by the production ratio (1.5) and panel wattage (400). That means you’d need 16 or so solar panels

Again, this is a simplified illustration, and the other factors we’ve discussed are also considered to calculate how many solar panels do I need.


Consult Your Local TruHome Solar Professional

There’s a lot to consider here, and it’s not the kind of thing you can guess about and maybe adjust if things don’t turn out exactly as you thought. The best way to determine how many solar panels you need is to work with an experienced solar installer.

TruHome Pros can tell you exactly how many solar panels you need, show you the optimal layout, and which solar system will provide the best ROI and performance year round. We are located in Illinois, Michigan, and Wisconsin offering 5-star service with maximum savings.

Try Our Free Go Solar Calculator

to estimate your costs and savings!

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