Solar Panel Weight Considerations for Roofs

Using solar panels is becoming increasingly common for people around the world, especially in the U.S. Our roofs aren't only useful for protecting us from atmospheric changes like rain, snow, or heat. In fact, we can use them to install solar panels that help us generate the necessary power for our buildings.

With that being said, the first thing asked when installing solar panels is, can my roof handle solar panels? Here are a few things to keep in mind if you are interested in installing a solar power system on your roof.

Approximate Size and Weight of Residential Solar Panels

Solar panels commonly weigh between 20 to 50 pounds, depending on the size and type, averaging around 40 pounds for residential solar panels. They are distributed evenly using a racking system to support them. Solar panels can add about 2.3 to 2.8 pounds per square foot, depending on the type chosen. However, this figure is greatly impacted by a number of factors, including the pitch of the roof. Flat roofs could see weights of 4 to 5 pounds per square foot.

How big can solar panels be? On average, the size of solar panels are approximately 65 inches long by 39 inches by width, for the types of panels used in residential applications. Solar panels can also be used in smaller applications like for roofs of RVs or campers. Here are a few examples:

What Makes A Solar Panel So Heavy?

To answer this question we have to take a look at the components of the solar panel.

• Aluminum frame;
• Tempered glass;
• Stringed solar cells;
• Junction box;
• Encapsulation foil 1;
• Encapsulation foil 2;
• Back sheet.

Solar cells only weigh a few hundred grams. Most of the weight of a solar panel comes from the aluminum frame and glass. The material of the solar panel is also a very crucial point in the weight of the solar panel.

What Are The Types of Solar Panels?

Monocrystalline Panels

This type is known to be a little on the heavy side, as it's mostly used for commercial buildings. These panels tend to weigh about 50 pounds, but generate a substantial amount of energy, thus its use in commercial settings. However, they can sometimes be seen on residential buildings too.

Polycrystalline Panels

Polycrystalline panels didn't gain much foothold in the market initially. However, many improvements through the years combined with a more affordable price made them a more common choice for households. These types of panels have an average weight of around 42 pounds, and although they are not as energy-efficient as the monocrystalline panels, they are more affordable and perform well.

How Many Panels Are Needed?

The number of solar panels used varies depending on one's use of energy and overall power needs. The first thing to do is to consider the daily electric needs like lights, fans, appliances, etc., before determining how many watts you need to power up your house.

Once you know your energy usage, you can figure out how any panels you'll need. Generally speaking, around 11,000 kWh of electricity is generated for home use annually in the U.S. That's equal to using 250 kW solar panels, which is roughly 28-34 panels per household.

Is Your Roof Suitable for Installing Solar Panels?

It's important to determine whether your roof can handle the weight of solar panels. To determine this, you'll need to calculate the number of solar panels you'll need, along with the weight of each panel.

For example, in the case of a 6kW solar installation, which consists of 20 solar panels, that's about 700 to 800 pounds, depending on the type of solar panel selected. This translates to 2.3 to 3 pounds per square foot.

Most modern homes can handle over 3 pounds per square foot of weight easily. However, it's always prudent to engage the services of a professional (such as an architect or structural engineer). They can examine your roof for suitability, or make recommendations if adjustments are required.

Will the weight of snow affect the solar panels on the roof?

People who live in snowy climates have to take into consideration the additional weight of snow, on top of the weight of the solar panels. Again, a structural engineer or a company that specializes in installing solar panels can help you determine whether your roof can handle the load.

Last thoughts

Should your roof be able to handle the weight of solar panels, integrating solar energy into your home can be an attractive option. With all the benefits solar energy provides, more people are moving in this direction. It has been proven that solar power systems help to save money by reducing power bills over time, and may even help to increase the value of a home. Solar power also contributes to the protection of the environment by using a cleaner energy source and reducing your carbon footprint.