Do you plan to have solar panels mounted on your roof? If you do, one of the things you need to ensure is that your structure can support the additional weight. Your solar panels will pack at least a few extra pounds per square inch for each solar cell. You also need to add the weight of the equipment used to mount them. On a roof that is not sound, that additional weight is a recipe for disaster. In this regard, you need to ask yourself how much do solar panels weigh?
In our article, we will answer this question for you. We will also address every other concern you may have about the weight of solar panels on your roof.
You need to have this information before you mount solar panels on your roof. Because you will not get the go-ahead to install panels on your rooftop if it is a potential hazard.
Table of Contents
The Size Of Solar Panels
There is no exact size and weight for solar panels. That’s because they are designed for different purposes by different manufacturers. So, you will find their dimensions and weight varies to a slight degree. These are some of the things which determines how big or heavy a solar panel is.
Residential Solar Panel Size
The average dimensions for residential solar panels are 65 inches x 39 inches. That translates to 5.4 ft x 3.25 feet. Because solar panel designs differ by manufacturer, they might be smaller or larger. The difference is most times, no more than an inch in both length and width. Usually, this is due to the type of material used to frame the panels.
Commercial Solar Panel Size
Commercial solar panels are no different. On average, these solar panels are 78 inches in height by 39 inches in width. They are closer to six feet with slight variations based on the manufacturer.
Number of Cells In Residential Solar Panels
Part of solar panels is photovoltaic cells that trap sunlight to power your system. You will find a number of these cells in all solar panels. The more there are, the bigger the solar panel, and the heavier it will be.
All photovoltaic cells have a standard size of about 6 inches x 6 inches or 156mm x 156mm.
Your standard residential rooftop solar panels come with 60 of those cells. That’s why you will notice that these designs have 6-inch x 6-inch squares in a 6 by 10 grid. These are the more common residential solar panels.
Number Of Cells In Commercial Solar Panels
Standard commercial solar panels have about 72 to 98 cells or more. 72 cell count panels are the most common of these types. They have six cells laid across by 12 cells tall. They are the same width as a 60 cell panel but are about 13 inches taller.
Residential vs Commercial Solar Panel Roof Installation
The most frequently used cell count for commercial projects is 72. Whereas the most common cell count for residential projects is 60. But the name commercial is a bit misleading. It suggests that these cells are for commercial purposes only when that is not the case.
It is perfectly alright to install commercial-sized panels on residential rooftops. They are larger, have more cells, trap more sunlight, and so will produce more power. But, they will also be more expensive and weigh more.
Large homes need a sizeable system. The commercial-sized panels are especially suitable.
But larger panels mean more weight your roof has to be able to afford. Your structure may not be strong enough to support the heft of a commercial-sized system. A lesser residential-sized system can work just as well.
Solar Panel System Installation Size
The number of solar panels you need depends on a number of things. The four most important to consider are:
- The location of your property
- How much power does your house use each year
- How much electricity do you want to generate
- The price of power in your area
But none of these will matter if your roof is not in a condition to support your solar panel setup.
So let’s take a look at average sizes and what it means for the extra weight on your roof.
The system you choose must be worth your while. It has to save you money. Otherwise, going solar makes no sense. Most panels have a 230-275 watt rating. So you may need between 20 and 35 panels to generate enough electricity to power your home. Those numbers are a reflection of the national average.
Remember, an average residential-sized system measures 65×39 inches. Let’s say your system is 6 kilowatts with 20 of these panels. That’s an accumulated measurement with a width of 27 feet and 13 feet in length. In shorter figures, you are looking at an extra 352 square feet added to your structure.
And, of course, the number of panels you erect on your roof depends on if your structure can support them.
Whether your roof can sustain the size system you need is the relevant question.
How Much Do Solar Panels Weigh?
Solar panels are not very heavy but you are looking at an added 327 square feet on your roof. Since you have to install them outside, they have a sturdy build to survive the weather. And based on their dimensions and framing materials, they have different weights. That weight does not include all the hardware you need to use to mount them.
Solar panels range from 60 to 144 cells. Here we will look at the breakdown of the weight of your standard solar panels.
Photovoltaic Solar Panels With 60 Cells
On average, these cells weigh about 35-40 pounds each. Most of the weight centers in the middle at about 40 pounds.
Weight Distribution
When mounting solar panels, the weight does not sit in one place on the roof. It spreads evenly over the surface area each panel occupies. So a solar panel of this size and weight distributes about 2.4 pounds over each square foot it covers.
Photovoltaic Solar Panel With 72 Cells
The average weight of a 72-cell panel is about 50 pounds.
Weight Distribution
The weight distribution of 72-cell, 50-pound commercial panels is close to the 60-cell. That’s surprising, but here’s the simple reason why.
The surface area the weight of these panels spread over is wider. So, although there is more to them, their weight distributes at only 2.4 pounds for each square foot they cover.
Note, these numbers do not include the mounting equipment as yet. They are lightweight implements. But their weight accumulates when you add up 20 or more of them. They can bring the weight of your panels up to about 4 pounds for each square foot.
Will Your Roof Support The Weight Of Solar Panels?
Most new homes have roofs designed to take the weight of a solar panel set up. For most older homes, this may not be the case.
To learn if your roof can support the weight of solar panels, you will need to have your structure inspected. The inspector has to be a certified structural engineer.
In many regions, the inspection may fall under some building code. Those laws may change from place to place. But in most areas, as long as you plan to install a system larger than 200mm, you must have a roof inspection.
Is Your Roof Solar Panel Install Ready?
The equipment used to mount solar panels is lightweight. But since you will need more than a single one, the weight adds up. The inspector/engineer will consider how much weight they will add to your setup.
They also need to take into account the solar panel installation process. Different types of roofs require different methods.
The city or the local government will most times oversee the entire process.
In the end, they will either approve your roof for solar panels or not. If you get the go-ahead, you can continue with your plans at your convenience. And if not, the inspector will make recommendations of how to get your roof solar panel ready.
These are some of the usual recommendations.
- roof repair
- partial roof replacement
- whole roof replacement
- adding support to beams
- adding support to rafters
Ground-mounted Solar Panel Setup
If your roof is not solar panel ready, there is another route you can take. You can use a ground-mounted solar panel setup. With this layout, weight does not matter. But that option is more expensive than a roof-mounted system.
Does a ground-mounted system cost more than getting your roof repaired or replaced? Consider the prices of getting the roof repaired or replaced and the roof fitted with solar panels. If it is still less expensive, then you should go ahead with a roof mount. The roof is the most ideal location for solar panels.
Is the ground-mounted system cheaper than a roof renovation? Will this setup provide the type of energy you need? If the answer to both these questions is yes, I would stick with that option.
Will Snow Increase The Weight Of Roof-Mounted Solar Panels
If you live in a wintery zone, you’re probably wondering if the snow will increase the weight of your panels. There is very little chance of that happening.
First, solar panels absorb sunlight even on a cold, snowy day. That means they will be warm. With their slick surface, the snow should not accumulate. It should slide right off.
Secondly, when mounting your panels, the engineers will take into account the snowfall in your area.
And most importantly, solar panels are pressure rated. The pressure rating measures how much-added weight a panel can handle before that extra weight causes damage.
With a 5,000 pascal rating, and sometimes more, your panels can handle about four feet of extra snow.
Will Solar Panels Damage The Roof?
Once a professional signs off on your solar panels, you should not need to worry about it hurting your roof.
Panels might hurt your roof if the installation crew did not install them the correct way. If they followed proper installation practices, there should not be any issues.
The Best Way To Arrange Solar Panels
Each type of roofing material, roof shape, and pitch will affect how the solar panels are mounted.
Knowing the type of roof you have is necessary to determine which solar product is best for you. It is one of the deciding factors in the type of set up you need.
You want to consider the following.
- Roofing material
There are different mounting methods for each type of roofing material. - Roof shape
An engineer has to consider the architecture of your roof. If your roof has a unique or complex design, your installer has to design a setup that gets the most from your panels. That set up must also not compromise the structure of your roof.
We can also discuss how steep your roof is and if there are any obstructions on the surface. Obstructions include chimneys, vents, and the like. Your installation crew has to work around these things and keep the output of your panels in mind.
You might think that you need as many panels possible. But most times, less is more. Less panels means that your small roof won’t be overladen. They just need to be positioned in a way that makes the most out of their purpose. - Roof Size
On a small and simple roof, less is more. A homeowner with a small roof should consider smaller and fewer panels. Larger commercial-sized panels can compromise your roof.
What your design needs to concentrate on is the efficacy of the panels that you have and not the volume. You only need a system that generates the amount of electricity your home uses.
Solar Panel Weight Can Affect Installation
Solar panels have come a long way. They are easier to set up and they work better. There is no doubt that they save money. But installing them takes more than simply mounting them on a roof. There has to be method and precision. Otherwise, you may end up spending more money than you planned to.
Installing solar panels the correct way begins with the right installer. Find an expert who is willing to walk you through the entire process.
It is never a wise idea to take shortcuts. Together, you can sit down and decide on a system that is the right and fit for you.
Do not go out and buy panels unless you’ve consulted an expert.
