Not Sure How Many Solar Panels Your Home Needs? Here’s How to Find Out


When your solar energy system is the right size, you’ll ensure that it can effectively meet your needs. To find out if a system is the right size, you’ll need to calculate how much electricity you use and how much electricity the system is capable of delivering. But now the question is: How do you do this?

In this post, we’ll look at the calculation in more detail, so that you can determine how many solar panels your home will need.

Understanding Your Power Usage

The first step in calculating how many solar panels you need is knowing how much electricity you actually use. This will underpin the calculation and ensure that you choose a system that can meet your needs. Fortunately, it’s quite straightforward to calculate this value. You only need to look at your monthly electricity bill or smart metre readings for the past and then calculate an average for the number of months you look at.

Solar Panel Output Options

You’ll also need to take into account the output of the solar panels you plan on using. Generally, you’ll use panels with outputs of between 300 and 400w, as they are gaining popularity. Remember, though, that based on your requirements you might need panels with higher or lower outputs.

Installation Considerations

Before you choose and install a system, you should also consider the roof space you have available. Generally, a 5kW solar system needs about 25m² of roof space. Thus, higher capacity systems need more space, and you should consider if you have the space available for a system that can meet your needs.

Also, you should consider the orientation of the panels. Ideally, solar panels should face north to ensure maximum sun exposure. However, if this is not a possibility, you can also install them to face east, west, or south. In this instance, though, they’ll be less efficient, which means you might need to install more panels.

Calculating the Size of Your Solar Energy System

Let’s now look at the steps you’ll need to follow to calculate the size of your solar energy system:

  • Calculate your electricity needs. We’ve already dealt with how you should calculate your average electricity usage, which shows you the needs that the solar system needs to meet.
  • Consider how much sunshine is available. Next, you should know how much sunshine your area gets. This is measured as peak sun hours and, ultimately, shows you how much electricity a solar system can generate. For example, if your area has 150 peak sun hours per month, a 1kW solar system will be capable of generating 150kWh of electricity.
  • Calculate the size of your system. Finally, you can calculate the size of the system. Here, you’ll divide your monthly electricity needs by the monthly peak sun hours. This means that, if you need 900kWh of electricity per month and your area has 150 peak sun hours, you’ll need a 6kW system. In turn, for a 6kW, or 6,000-watt system, you’ll need 20 panels if they have outputs of 300w.

Hopefully, this post helped illustrate how you would calculate the size of your solar system and, by implication, how many solar panels you need. The only thing you should do now is get in touch with a licensed electrician for your solar panel installation.