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Installing Solar Panels On A Flat Roof? Here’s What You Need to Know.

what you need to know about installing solar panels on a flat roof

To cut to the chase, solar panels work best when they’re installed at an angle facing the sun. However, that doesn’t mean installing solar panels on a flat roof isn’t possible – because it absolutely is.

So, today, I’m going to clear up a lot of things for you so you can also save money on your power bills. Below is a list of the topics and questions I’m covering in this post. I recommend reading from the top but feel free to tap on any of the bullets to jump straight to their sections.

Can you install solar panels on flat roofs?

As I said, yes, you can install solar panels on a flat roof. In fact, flat roofs offer more versatile installations than sloped roofs.

With the right mounting system, your installer can orient your system in angles and orientations that are more optimal to your needs and power output. You also have the option to just have the solar panels installed flat (though I don’t recommend it).

That being said, each installation type also has its own set of pros and cons. Let’s talk about each of them so you know your options.

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The best solar panel orientations for flat roofs

Before anything, note that all of the orientations I’m about to highlight need racking systems, so mention this to your installer when you’re in conversation.

Also, we have an article dedicated to the directions solar panels should face in Australia if you want to learn more about that, too. So, without further ado…

Identify which is the best solar panel position for Flat Roofs

Purely east, west, or north-facing solar panels

Like Australian homes with roofs facing north, flat roofs with solar panels tilted north will enjoy a large amount of solar energy. That’s because our land down under is in the southern hemisphere, so the sun moves towards the north.

On the other hand, solar panels tilted to the east enjoy more power during the early morning while west-tilted panels have more energy in the afternoon.

North is the safest option but east or west can be better for you depending on the hours you use the most electricity.

That being said, these single orientations also have their drawbacks. You can’t install them too close because they can cast shadows on each other which limits their efficiency. This, in turn, limits the number of solar panels you can install on your roof.

Mixed (east-west) orientations

Out of all the possible ways to install solar panels on flat roofs, I like this best.

Here, you have one row of solar panels facing east, and right behind it is another row facing west. Repeat as many times as your roof and budget allow.

Shading isn’t so much of an issue here, allowing you to install the most solar panels because rows can be installed right next to each other. And when you have more solar panels, you’re also able to generate more energy.

The caveat is that it’s more expensive and not many installers accept this kind of project. Lucky for you, we can get you quotes from 3 of our pre-vetted installers – for FREE! The more installers you ask, the better your chances of finding someone who can take on this project.

What about solar panels that are installed flat or tilted south? Why not them?

I don’t recommend south-facing panels to Aussies because it faces away from the sun. Meaning, they generate the least amount of energy in total.

On the other hand, yes, you can install solar panels flat on your roof. This way gets you cheap installation costs and a decent amount of energy.

The problem with flat solar panels, however, is that they’re not self-cleaning and are therefore impractical for many.

Rainwater can pool above the panels, so dust and other debris don’t get washed away. Over time, this can decrease the efficiency and prematurely age your system. I can only recommend this in good conscience if you’re willing to regularly clean, dry, and maintain your solar panels.

Is it cheaper and easier to install solar panels for flat roofs?

Installing solar panels on a flat roof and a sloped roof tend to be around the same price, which is about 1000 AUD per kW. Although, this price still depends on your installer and the rack he/she will use.

That being said, flat roof solar panels are typically easier to mount because there’s more space to work around. It’s also safer.

Also, installing solar panels on flat roofs generally won’t require your installer to drill holes either because most of today’s racking systems have enough weight to keep the array stable.

On that note, do tell your installer to use a rack that can withstand heavy winds so your solar panels don’t get blown away.

Other things you should know about before getting solar panels for a flat roof:

  • Make sure to check with the manufacturer and installer if their warranty covers solar panels on a flat roof.
  • Make sure your roof is strong enough to carry the weight of your solar panel system. These weighted racks (i.e. ballast system) make this a necessity.
  • Your flat roof solar panels likely won’t be visible from the ground, so they won’t take anything away from the beauty of your home.
  • While installation might sometimes be more costly, you will still save more money over time because you won’t be as reliant on the grid.

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Key takeaways: Pros and cons of solar panels on flat roofs

Pros:

  • Flat roof systems offer more versatility when it comes to orientations (directions and angles).
  • Flat roof solar panels are cheaper to install; angled solar panels are more efficient and self-cleaning.
  • Installation costs for a flat solar panel system are about the same as sloped roofs. Sometimes higher.
  • Flat roofs are easier and safer for your installer.
  • Weighted racking systems mean no holes will be drilled on your roof.

Cons:

  • Installers who accept jobs on flat roofs are harder to find.
  • Flat roof solar panels will require more cleaning.
  • Flat roof solar panels will have water pooling on top of it, possibly leading to damage.
  • Wind damage is a possibility with panels that are installed on unfitting racks.

Conclusion

To recap, yes, you can install solar panels on your flat roof but it will be a slightly different process.

For one, you will have to figure out what orientation best fits your lifestyle and one that maximizes your roof space and budget. Your roof also has to be strong enough to handle the weight of the racking system as well as the entire array.

I hope this helped! And, remember, if you’re having trouble finding an installer for your flat roof, we have a network of installers that we trust. You can trust them, too.