If you live under a flat roof, you might wonder if you can add solar panels to it. In most cases, a flat roof is just one of many factors to consider when thinking about home solar panels. In fact, a flat roof allows you to pick the angle of installation for your panels, maximizing your investment and getting optimal energy efficiency.
In this article about solar panels and flat roofs, we’ll outline how the specifics of your roof are important to getting the most from your solar investment and how you can make the best decision for your home.
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Flat Roofs and Solar Panels
The majority of residential roofs in the US are pitched. However, many Americans live in a home with a flat roof – in modern condos, adobe-style homes, dense urban areas, and more. And, the sun shines on a flat roof the same as an angled roof, right?
In fact, flat roofs and solar panels can work very well together, especially at larger scales – which is why solar panels are frequently on the flat roofs of commercial buildings like retail centers, offices, and manufacturing facilities.
However, a flat roof does require a bit more equipment and may have some limiting factors. For instance, does your roof have the space needed for solar panels? On the other hand, a flat roof installation may be more productive than some on pitched roofs.
Pros and Cons of Solar Panels on a Flat Roof
Having a flat roof may increase the cost of your solar energy system compared to a house with a pitched roofline.
While solar panels can lay flat against a slanted roof, a system installed on a flat roof must be raised and tilted to receive direct sunlight, which can increase your project's material costs. That said, this may actually result in better peak performance and long-term benefits as systems on a flat roof can be oriented to the best angle for solar panel efficiency on your specific property.
Pros with panels on a flat roof
- Perfect angle: On a flat roof, solar panels can be installed onto racking systems at the perfect angle for sunlight absorption and energy generation.
- Roof space: Flat roofs may have more usable space and less shade.
- Easier maintenance: Flat roofs can be easier and safer to work on.
- Cost: Depending on other factors, installation could be simpler and less expensive.
Cons with panels on a flat roof
- Cost: If extra mounting materials, structural reinforcements, or other components are needed, the cost could be more on a flat roof.
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Considerations for Solar Panels on Flat Roofs
Having a flat roof does not necessarily limit your ability to use solar power and save money. You may have extra installation considerations, though.
A flat roof may present interesting opportunities that pitched roofs can’t accommodate. For example, with the right home design, you may be able to install a solar canopy on a flat roof that creates a shaded outdoor area below its raised panels.
Any solar project, on any roof, has safety considerations and that’s part of why it’s best left to pros. Particularly with a flat roof, existing drainage problems, cracks, or damage should be checked and resolved before installing a system on it.
Solar panel installations on a flat roof can have extra needs and expenses. More of the panel weight is a strain on a flat roof than an angled roof, so additional reinforcements or components may be needed. The tilting needed for a solar array on a flat roof may be more expensive.
In designing your flat roof solar panel system, you must abide by local building ordinances expressly set for flat roofs. These ordinances may limit the overall availability of your installation space if your panels must have a solar setback from the roof edges, vents, or skylights.
Should You Install Solar Panels Horizontally?
Even if your home has a flat roof, and the sun shines brightly on the roof, it’s typically not a good idea to install solar panels flat across the flat roof.
Unless they’re very close to the equator, solar panels should be angled to maximize the time of the day when the sunlight is hitting the panels at or close to a 90-degree angle. In the lower 48 of the US, the northern latitude spans from 24.5 degrees in Key West, Florida to 49.2 degrees in Angle Inlet, Minnesota.
This will give you the most efficient energy generation, predictable production, and better long-term financial results — such as the shortest possible solar payback period — from your system.
Panels could be at more risk of damage, need more cleaning, or have periods of less generation due to debris or pooling water.
Designing the Optimal Solar System for Your Home
Whether your roof is flat, pitched, or yet to be built, Palmetto can help you discover your home’s solar potential. Going solar with an experienced, professional team to help each step of the way and answer your questions should lead to a long-term relationship. After all, solar panels should last and give you clean, independent energy for 25 or more years.
To learn more about saving money and clean energy for your home, use our free solar savings calculator or contact us.
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Frequently Asked Questions
Can you put solar panels on a flat roof?
Yes. A flat roof can be ideal for a very effective solar panel system. If solar panels will make good energy and financial sense on a flat roof depends on the roof and a number of other factors.
Are solar panels too heavy on a flat roof?
If a roof, flat or any other shape, is damaged, leaking, very old, or having draining problems, it’s recommended to fix those problems prior to installing solar panels. Solar panels and a system’s other components are not too heavy for a roof in good condition.
Will solar panels on a flat roof leak?
Solar panels on a flat roof are more susceptible to causing leaking. Water is more likely to pool on a flat roof in general. If a roof is older or damaged, solar panel installation without the proper inspection, components, or weatherproofing could cause a bigger problem. This is why you should always get solar panels installed by a company that can advise you on the health of your roof and install the panels so they won’t leak.
What is the best angle for solar panels?
In the US aside from Alaska and Hawaii, the best angle for solar panels ranges from 25-49 degrees. This angle is calculated to maximize the time panels are perpendicular to the most-direct sunlight time in a year.
Andrew GiermakWriter and EditorAndrew joined Palmetto in Charlotte in August 2024. He’s been a writer in journalism, then in business, going back to almost the 20th century. He’s lived in Indiana, Virginia, Pennsylvania, Virginia again, and now North Carolina for the last 12 years. He likes golf. Is he good at it? Not so much.
