Calculating Your Solar Panel Needs – How Many Panels Do You Need?

Switching to solar energy is a big decision and requires careful assessment of your electricity usage, location, and home size. Understanding how to calculate your solar panel will help ensure you have an array appropriately sized for your energy goals and climate.

First, gather your utility bills and determine your yearly average electricity usage. From there, you can estimate your hourly power generation needs.

Solar Panels

If you’re considering solar, it’s essential to determine how many solar panels do I need before moving forward. Doing so will help you make a more informed decision and reduce the risk of buying too few or too many meetings, which can impact how much energy your system generates.

Calculating the number of solar panels you need requires some essential information. The three most important are your household energy usage, your roof’s surface area, and the peak sun hours for your location. The energy consumption figure is the easiest to get from your utility bills. You’ll also need to know the wattage and production ratio of the solar panel types you’re considering.

The average daily kWh energy usage is then multiplied by the number of peak sun hours for your location to calculate how much power your panels need to generate hourly. This figure is then divided by your panel wattage to find the number of meetings required for the project.

Once you have this information, the best way to make an informed choice is to work with a local solar professional. These experts are familiar with the local climate and have the experience to maximize panel placement while considering add-ons such as electric vehicle charging or a backyard greenhouse. Plus, they can provide detailed quotes based on your home’s size and power needs.

Roof Space

The first step in determining the right solar system size for your home is understanding how much energy your household uses. This is typically shown on your electric bill in kilowatt-hours (kWh). While this number may fluctuate monthly, it’s best to use a yearly average to give you the most accurate picture of your power consumption.

You must also consider what kind of roof you have, as the orientation is essential in determining how many panels your house can support. Generally, rooftop solar systems should be oriented with the sun facing south. This helps maximize energy production, and while you can install it on a roof that meets other directions, the performance will be lower than if your roof faced south.

If you’re unsure about the size of your roof or its ability to support a solar array, the team at Palmetto can help. We can perform a free solar evaluation of your home and offer suggestions on optimizing your roof space. We’ll also ensure that your roof can support the weight of a solar panel installation, which is about 40 pounds per panel. *Note that the weight of a panel will vary by brand, being among the lightest panels on the market.

Electricity Usage

A solar panel’s wattage – its power rating – is the amount of electricity it can produce on a sunny day. This metric determines how much energy you can get off the grid by replacing traditional sources with solar power.

The best way to figure out how many solar panels you need for your home is to look at past utility bills and then multiply your average monthly energy usage by the number of peak sunlight hours in your area. Then, use the resulting number of solar panels to calculate how many kilowatt-hours (kWh) you’ll need each day.

Remember, however, that you’ll need a buffer when your electricity usage goes up, such as when there’s a three-day bout of rain or a significant snowfall in the winter. For this reason, it’s often recommended that homeowners install 25% more solar panels than their average daily usage.

Other variables can impact the number of solar panels you need, such as your geographic location and the type of solar panel you choose. Homes in southwestern states, for example, receive more sunlight than those in the northeast, and panel wattages vary from manufacturer to manufacturer. If you decide to work with a solar installation company, they’ll consider these factors during your consultation and evaluation of your roof space.


Solar panels require little maintenance but are not impervious to damage and deterioration. If a meeting is hit by debris like dead birds, falling branches, or a three-day bout of hail that leaves a coating of ice on your boards, it can cause power loss and need to be cleaned.

Monitoring energy output is the best way to determine if your solar system needs maintenance. Many companies offer apps or physical trackers that allow you to see your solar electricity production daily or weekly. Over time, you will get a good sense of your average performance. It may be time for a maintenance check if it is starting to reduce – even if it is just a tiny amount each week or month.

As a rule, you should clean your panels once or twice yearly. You can wash them with a garden hose or a sponge to remove dust, pollutants, and any bird droppings that have built up on the surface. During wildfire season, you should also inspect your solar panels for ash or soot build-up, as they are particularly susceptible to damage from fires near your home or business. A simple cleaning will usually restore your solar system to peak performance.