One thing that might concern you is the weight of solar panels.
Solar panels are becoming bigger and heavier as manufacturers look to increase power capabilities.
Of course, the best place to mount a solar panel is on your roof where you have unused sunny space.
Before you decide to install a huge solar array, you should understand the weight of solar panels to ensure your building can support them.
It’s not going to be fun if your roof collapses, is it?
Happily, the increasing number of homes with solar panels shows that weight shouldn’t be a problem for most.
So let’s take a look at how much a solar panel weighs and if your roof is suitable.
How Much Do Solar Panels Weigh?
The average residential solar panel weighs between 40 and 60 pounds. That’s 20 to 30 kilograms.
The weight of a solar panel varies depending on the size and brand but you can stick to the rule of 2.5 pounds (1.1kg) per square foot.
Difference in weight is largely down to the size of your panels. On a home roof, you will either have 60 cell or 72 cell panels.
- 60 cell solar panel weighs about 40 pounds, produces 280 watts and is about 17 square feet in size.
- 72 cell solar panel weighs about 50 – 55 pounds and produces 350 watts and is 21 square feet in size.
Is Your Roof Strong Enough for Solar Panels?
Now you know how heavy solar panels systems can be, you will be able to understand if your roof is strong enough.
Let’s look at an example of the total weight of a residential system. This will give you a clearer understanding of what needs to be supported.
The most common system is eighteen 60 cell solar panels which weigh around 700 pounds and cover 306 square feet of your roof.
Adding to this, you will need to account for the mounting equipment such as brackets, junction boxes, and wiring. This adds extra weight to give a true figure of 3 pounds per square foot.
Knowing that the system is 306 square feet we can multiply this by 3 pounds for a true answer. 306 x 3 = 918 lbs.
Ask a Structural Engineer or Surveyor
To be sure your roof is in good working order and strong enough to support your chosen equipment you should consult a structural engineer. They will be able to give you a detailed report and spot any potential issues.
Remember, solar panels are designed to work for decades, at least 25 years! So you need to ensure your roof will last just as long. Many people decide to reroof their property before installing solar panels to ensure the best long term investment.
Solar Panel Weight Comparison
For your reference, here’s a handy comparison table of different solar panels and their weight.
So far we’ve discussed 60 cell and 72 cell residential solar panels.
But there’s a number of other different size and power options for off-grid solutions on vans, RVs, boats, and cabins. Let’s look at how heavy other size solar panels are:
What weight is a 100 watt solar panel?
A 100 watt solar panel weighs an average of 14 lbs. For example, the Renogy 100W is 14.3 lbs, while the Newpowa 100W is lighter at exactly 14lbs.
You can also get portable solar panels in this size which weigh 7 – 10 lbs. Plus flexible 100W solar panels weigh less than 4 lbs!
How heavy is a 200 watt solar panel?
A 200 watt solar panel weighs an average of 25 – 30 lbs. For example, the Newpowa 200W is 27.5 lbs, while the Rich Solar 200W is lighter at 26.5 lbs.
You can also get portable solar panels in this size, such as the BLUETTI SP200, which is 14.3 lbs. It is rare to find a flexible solar panel in this size, so you would need to use two 100 watt solar panels which would total less than 8 lbs.
Will Snow on Solar Panels Be Too Heavy for a Roof?
If you live in a region which experiences heavy snowfall during the winter then you need to think about this added weight.
Rooftop snow build up can be a danger even without solar panels. This is for two reasons. Firstly, can your rooftop support the weight? Secondly, large chunks of snow falling off rooftops can be dangerous.
The weight of snow varies depending on its moisture content. As a rule of thumb, it weighs 20 lbs per cubic foot. Or 1.25 lbs per inch of depth
That means you could have a lot of extra mass sitting on your roof during winter! While your solar panels will be fine, you might need to clear the snow to protect your building.
In addition, buildings are often winterized with snow guards to stop large chunks falling off. Your solar panels won’t always have these guards built in so could lead to melting snow slipping off onto the ground below. This could be dangerous in a high traffic area. If this could be a problem then speak to an installer about adding snow spikes.
Why Are Solar Panels So Heavy?
So why are traditional solar panels so heavy? After all, if flexible solar panels are 70% lighter, why don’t residential ones weigh less?
Well, it’s all to do with quality and durability. Rooftop solar panels need to deliver high performance for decades. This means they are built using stronger materials that are heavier.
Rigid solar panels have hard wearing aluminum frames and tempered glass to protect the solar cells. This makes them incredibly durable and resistant to adverse weather including rain, wind, and snow.
Can Solar Panels Collapse a Roof?
Generally, your roof should be able to support solar panels. However, they are heavy pieces of equipment and can lead to a collapsed roof. This would be very dangerous to people inside the building and be very expensive to repair. You should always consult experts when installing a large solar array. For example, the stadium roof of Dutch football team AZ Alkmaar collapsed due to extra weight of solar panels.
Final Words on Solar Panel Weight
As you can see, knowing how heavy your solar panels are is important when carrying out an installation.
If you apply too much pressure to your roof it could collapse which is expensive and dangerous.
Even if you don’t require extra permits, you should have a professional carry out surveys and calculations to ensure your roof can support the weight.
As a general rule, you can work to the figure of 4 lbs per square foot to be safe in your calculations of total weight including mounting brackets and cables.
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.