A: It all depends on the amount of electricity consumption that a particular house uses on a monthly basis.

Ok—that probably wasn’t the answer you were wanting to hear. We completely understand, but in all honesty, it truly is hard to say as there are so many variables to consider. However, we’ll do our best to expound on this with as much detail as possible.

So, for the sake of getting a rough idea of what it takes to run a home, let’s cover some of the basics. The typical American home will need anywhere from 15-35 solar panels—give or take a few, to power their home. Keep in mind that those panels must be mounted somewhere as well. So, the typical home will also need at least a little over 220 square feet of rooftop space to mount the panels.

Solar panels absorb and produce energy, the amount at which they do that is measured in kilowatts (kW). Similarly, the amount of electricity your home consumes over your monthly billing cycle is measured in kilowatt-hours (kWh).

It’s critical to know how many kWh your home consumes regularly. This is important so that you can equip your home with the right amount of solar-generated energy. Your array of solar panels needs to produce equal to your consumption or greater to negate electricity costs. Knowing your home’s consumption will also help you determine how many panels your array needs to contain.

So in answering the burning question of the day, we’re going to approach it from our installers’ perspective. We will be discussing the factors that they take into consideration when recommending the proper solar panel array for your home.

What Factors Affect The Number Of Solar Panels My Home Needs?

This would’ve been a much better question to ask because it gets to the heart of the matter. It doesn’t matter how big or small your home is. A smaller home can use just as much electricity as a large home. In actuality, electric consumption is a combination of your habits, needs, and external factors.

So, to determine how many solar panels needed to offset your energy consumption you need the following info:

  1. How Much Energy Your Home Uses: The monthly kWh used is usually listed towards the bottom of most electricity bills.
  2. The Direction Your Roof Faces: Here in the northern hemisphere roofs that face the southern sky get more sunlight exposure than those that face north.
  3. How Much Sunshine You Receive In Your Area: Here in Houston, we may not get quite as much sun as say, El Paso or Phoenix. However, if you’ve ever suffered through a Houston summer, you know we get a lot—between thunderstorms that is.
  4. Which Solar Panels You Are Considering: Solar panels come in all different types of configurations and efficiency ratings. Our technicians can help you choose, but it will play a part in how many panels you’ll need.

Now that you know the data you need let’s walk through how to calculate how many solar panels it’s going to take to power your home.

Putting It All Together

Do you know how many solar panels it takes to cancel out 1,000 kWh of electricity use in a month?

According to the U.S. Energy Information Administration, the average monthly consumption of electricity for the average home in 2019 was 877 kWh. That translates into roughly 29 kWh daily, and a little over 10,640 kWh annually.

Granted, all homes are unique as the homeowner’s consumption habits—a single woman is likely to use less than a family of four. A person that reads more than watches TV will likely use less than a gamer or home theater enthusiast. We could make comparisons all day long—you get the point we’re making.

So, to calculate how many panels you need to power your home follow the steps below:

Step 1: Determine your monthly electricity consumption.

Grab your most recent bill from Reliant or whoever your provider is. Towards the bottom, you should see the total amount of electricity you used during the billing period. If you go on your provider website, many also have tools to show your usage trends in detail.

Let’s work with some sample numbers to put it into perspective. Let’s say we have a home that used 877 kWh. So, multiply the KwH by the base rate— let’s say $.09/KwH plus various surcharges and you get your total monthly cost for electricity. We’ll ballpark it at let’s say, $115 after including various fees all providers charge in addition to the base.

Step 2: Determine the direction your roof faces.

Every home is different—one could consume more or less electricity than the average home. Some external factors will impact the effectiveness of the solar panels you install. Some of these factors include the direction of your roof, the amount of shade it gets, and your climate zone.

If you have a roof that faces the southern sky with no shade cover—you’re golden, move on to the next step. However, if your roof gets substantial shade from a tree or a large structure or it doesn’t face south, our installers can work around that. Therefore, it just comes down to a compromise that you are happy with but also gives maximum sun exposure.

Step 3: How much sunlight does your home get?

The size of the solar array your home requires depends on your consumption and the climate you live in. Houston homes on average use almost 14,000 kWh annually which translates to a solar system size of around 10kW. To generate that amount of electricity it will take roughly 36 solar panels—assuming they are 280-watt panels.  Now, whether those panels can be installed on your roof or not is another matter.

Now, it’s important to keep in mind that your energy usage may vary quite a bit from the Houston average. That is why it’s important to gather the most accurate data for your situation, to make a proper determination. Once you have all your factors lined up, you’ll need to choose the solar panels that are right for you.

Step 4: What wattage solar panel should I buy?

Earlier we mentioned using 280-watt solar panels. What we are talking about is the output those solar panels deliver. Usually, panels put out between 240 to over 400 watts per panel. Even if you know the number of solar panels you need, it won’t help if your roof can’t fit them. The higher the wattage the more efficient the solar panel because it can output more power—which means fewer panels are needed.

In the chart below, we layout the space needed for solar systems from 5 kW to 15 kW of total system power. Depending on your available roof space you may want to go with the highest efficiency panels if space is an issue. The higher the efficiency of the panels the fewer individual panels you will need to generate sufficient power. However, if your budget is an issue but roof space is not, you could opt for less efficient panels. They take up more room since you need more to output the required power, but they do cost less.

Approximate Space Needed For Residential Solar Array
System size Square footage needed for low efficiency (16%)Square footage needed for medium efficiency (18%)Square footage needed for high efficiency (22%)
5 kW315280230
10 kW627558457
15 kW940835684

Are Solar Panels Right For My Home?

Most homes will have ample space to accommodate enough solar panels to offset their electricity needs. The best way to make sure you’re going about it the right way is to speak with one of our consultants.

Let us help you get started on your solar journey with a no-obligation estimate. Just contact us today and we will schedule one for you.


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