What Is the Best Roof for Solar Panels?
September 14, 2021
If you’re looking to acquire solar panels, your first step is to determine whether your roof is suitable for a solar panel system. And if you plan to use solar panels on a home you’re building, roof design should be on your mind as well.
Either way, roofing styles and materials come in many different types. Understanding how these factors influence solar panel installations can be challenging.
At Freedom Solar, we’ll give you insights about which roofs work best for solar panels. When you know the best roof for solar panels at your home, you’ll make sure your system stays stable and secure for optimal performance.
What Type of Roof Is Best for Solar Panels?
Many types of roofs work great for solar panels, but here are the top types to choose from.
Mounting Solar Panels on Shingle Roofs
Image by JamesDeMers from Pixabay
Shingle roofs are the most common type of roofing on homes and comprise either composite or asphalt shingles. Composite shingles are made of a combination of materials, such as laminate, wood and slate. Asphalt shingles are made of either a cellulose mat or fiberglass, with asphalt added at the end of the manufacturing process.
While both options are flexible, composite shingles are a bit more durable than their asphalt counterpart.
Overall, installing solar panels on shingle roofs is quite simple, requiring standard penetrating mounts that easily attach.
For installation, technicians drill studs into the roof for the solar panels to attach to. Then, they close off the spaces between the panels and studs. Finally, they seal the system with flashings to prevent water from leaking between the roof and panels — and potentially into your home.
Many homeowners (or homebuilders) use shingle roofing because it’s inexpensive and durable. In fact, shingle roofing lasts between 12 and 20 years, which makes it great for attaching solar panels that you’ll likely keep on your roof for decades.
Mounting Solar Panels on Metal Roofs
Image by sam_higgins_rulz from Pixabay
Metal roofs work great for solar panel installations. If your home has a metal roof with standing seams, technicians can easily attach solar panels because they don’t require any drilling for attachment. And because there’s no need for drilling, there’s no need to hire contractors or crews, which saves you labor costs during the home solar panel installation process.
Additionally, metal roofs are beneficial on homes and businesses in sunny, warm areas — such as Texas, Colorado and Florida. That’s because metal roofs reflect any light that doesn’t hit solar panels, which keeps houses and buildings cooler.
One of the main reasons that people choose metal roofing for their homes is because of its impressive life cycle. A metal roof can last anywhere from 40 to 125-plus years.
On the downside, metal roofs are about two to three times more expensive than other roofing materials and can be noisy during inclement weather. Luckily, if you have solar panels on your home, the panel system blocks some of the noise.
Mounting Solar Panels on Tile Roofs
If you have a tile roof, technicians can install solar panels using a standard penetrating mount that raises them slightly above the roof. Because tiles don’t always have uniform shapes, cutting or removing some tiles might be necessary to make way for mounts. In turn, this effort can result in extra labor costs.
Tile shingles can be made of slate, concrete and clay. Installing solar panels on clay tile presents some hurdles that aren’t present with standard shingle roofs.
For one, how you move across the roof itself is radically different. Clay tile is highly resilient to the elements, but it’s not so resilient to installation teams’ footsteps. However, Freedom Solar is meticulous when servicing this market — we’re well trained on moving across clay roofs without breaking tiles.
Although tiled roofs are visually pleasing because they have more range in appearance, they’re typically heavier and more expensive than other roofing materials. (Granted, they’re not as expensive as metal roofs.) Nonetheless, they’re long-lasting and generally more waterproof than other roofing types.
Tile roofing is widespread in California and Arizona, and it’s growing in popularity nationwide. For example, in areas like Central Texas, preferences are changing alongside spiking population rates.
Mounting Solar Panels on Tar and Gravel Roofs
Although most tar and gravel rooftops are flat (some sloped roofs use tar and gravel), you can still install solar panels on them. However, you’ll need to ensure technicians mount and angle your solar panel system at 30 degrees with tilt brackets. This guarantees your panels receive optimal sunlight for energy generation.
And even though working on flat roofs is easy, you should still consider hiring a labor crew or contractor to mount and orient your solar panel system. This is doubly true if you’re inexperienced with the installation process.
Many homeowners like tar and gravel rooftops because they’re budget-friendly and have about a 20- to 25-year life span. Plus, they have tight seals to prevent cracks and leaks and provide a strong, flat support surface for your solar panel system.
[Related: Here’s What You Need To Know Before Installing Solar Panels on Your Home]
What Is the Best Roof Angle for Solar Panels?
Ultimately, the best roof angle for solar panels is about 30 degrees to maximize energy output. However, that doesn’t mean solar panels won’t work for roofs with steeper or flatter slopes.
For optimal solar panel performance, you’ll want to add 15 degrees to your latitude in the winter, then tilt the solar panel system to whatever that number is. For the summer, subtract 15 degrees from your latitude and angle the solar panel system accordingly.
Can a Roof Be Too Steep for Solar Panels?
Most roofs aren’t extremely steep. Even if yours is, your solar panels will likely still function well enough to produce enough energy for your home. Although the ideal roof angle is about 30 degrees, if your roof tilt is at 40 degrees, this decreases energy generation by only about 1%.
Any roof that’s over 40 degrees is probably too steep. If full energy independence is your goal, then a solar panel system might not be a feasible addition to your home.
Solar Panels on Flat Roofs
You can find solar panels just as easily on flat rooftops as on sloped rooftops.
The solar panel installation process for flat roofs is usually much simpler than it is for sloped roofs because it’s easier to move around. And that means the installation process is quicker.
Solar installations on flat roofs don’t need the penetration mounts that sloped roofs need for the system to stay secure. Alternatively, technicians use weighted mounting systems (aka ballast systems) for flat roofs, which don’t require drilling into the roof. This type of system eliminates the need for holes and uses gravity to ensure your solar panel system is stable.
However, because flat roofs clearly don’t have an angle, technicians use tilt-up brackets to keep your system angled at 30 degrees.
What Is the Best Direction for Solar Panels on Roofs?
The best direction for solar panels is south. But if your roof doesn’t face south, you can angle solar panels southeast or southwest.
Depending on which hemisphere you live in, this answer could be the opposite. For people in the Northern Hemisphere, the sun travels along the southern part of the sky as the Earth orbits throughout the year, so your solar panels need to face south. Similarly, people in the Southern Hemisphere need to angle solar panels north (or northeast or northwest).
How Much Roof Space Is Needed for Solar Panels?
The roof space you need for solar panels fully depends on your solar panel type and manufacturer, your home’s size and how much electricity you generally use daily.
For example, 1 square foot of roof space can generate around 15 watts of solar energy with an average-sized solar panel. A smaller home might need only 200 square feet of roof space for panels. However, larger homes would need more solar panels — and thus more roof space (about 1,000 square feet) — to keep the lights on.
If you use a lot of electricity, you’ll likely need more roof space to accommodate more solar panels to meet your power requirements.
Generally speaking, average homes use from 19 to 23 solar panels, with each panel needing up to 18 square feet of space. Your roof should have about 400 to 600 square feet of available space. Plus, consider any skylights, dormers or chimneys that might decrease your total usable roof space.
[Related: How Many Solar Panels Do I Need?]
Roof Strength Requirements for Solar Panels
Solar panels and their required mounting equipment, whether penetration or weight mounts, typically weigh 3 to 4 pounds per square foot. Usually, this weight is acceptable for any roof type.
However, solar panels with weighted ballasts on flat roofs generally weigh a bit more because concrete blocks hold the system in place.
As long as your home has a fairly new roof that’s in decent condition, weighted ballasts are a fine solution. That’s especially true if you have SunPower solar panels. SunPower offers the lightest solar panels in the industry, at about 33 pounds per panel.
Are Solar Panels Bad for Your Roof?
Solar panels aren’t bad for your roof, but you should consider some factors, especially during the installation process. Because drilling is necessary to secure panels to the roof, the process leaves holes that could lead to water leaks over time.
Solar professionals can ensure installation avoids long-term damage to your roof — and ultimately to your home. Because solar panel systems have a 30- to 35-year life cycle, it’s important that technicians install your panels correctly the first time around!
And while drilled holes in your roof never seem appealing, numerous safety measures help ensure drilling won’t result in any damage. We’ll tell you a bit about the process.
First, technicians use drilled holes for lag bolts, which secure the solar panel system’s mounting rack. To avoid water leakage, technicians fill the holes with a sealant. Then, they surround the lag bolts with metal or plastic flashings — a sort of shield that fits under whatever roof tile type you have. Finally, they seal the flashings air-tight with either tar or another durable material to ensure your roof doesn’t suffer damage or seepage.
[Related: Uninstalling and Reinstalling Solar Panels]
Solar Panel Design Considerations: How To Get the Best-Looking Solar Panels
If you’re worried that solar panels might make your home look … not as appealing as you’d like, remember that you have options!
For example, black shingles typically look best with solar panels. Although black absorbs sunlight, which can make your home feel a bit warmer, darker roofs help blend the appearance of solar panels so that they don’t drastically stand out.
At Freedom Solar, we offer SunPower solar panels in varying options. That said, their signature black aesthetic features all-black solar cells and antireflective glass, which look chic and sleek on any roof type.
And the benefits go beyond aesthetics. Whatever type of roof or solar panels you have, they’re a good look because they represent your character, values and commitment to sustainability.
[Related: 10 Questions To Ask Before You Consider Installing Solar Panels]
Contact Freedom Solar for Your Solar Panel Needs
To learn more about solar panels or the installation process for your home or business, contact Freedom Solar today! Call us at (877) 795-0577, or submit an online inquiry. We’re ready to help you go solar anytime.
Featured image credit: Ulrike Leone from Pixabay