If you’re looking to go solar at home, chances are you’re going to put those panels up on your roof. Ground-mounted solar is a great option, but it’s uncommon to have enough space to put up a decent-sized system in your yard. So that begs the question, what is the best roof design for solar panels?

Let’s get this out of the way first: Almost no one has the perfect roof for solar. Although some roof shapes and angles are better for solar production than others, solar panels are extremely versatile and can provide energy cost savings and carbon footprint reduction in a wide range of configurations.

In other words: Don’t let perfect be the enemy of good.

In this article, we’ll explore that makes a good roof for solar panels and some frequently asked questions.

Connect with an Energy Advisor to see how much sun your roof gets.

6 roof design traits that effect your solar production

There are several roof characteristics that effect how much your solar panels will produce. Here is the top six:

Orientation

Also known as azimuth, orientation is the direction your roof faces. For North American solar systems, the best roof design for solar panels is one with a large, unshaded south face (an azimuth of 180 degrees).

Not having a south-facing roof is not a deal-breaker. However, many roofs are multi-faceted, and if your roof is mostly west- and east-facing, you’re likely to only see a 10-20 percent reduction in the amount of energy you’re generating.

There’s been an ongoing debate about south-facing vs. west-facing panels over the last couple of years. While south-facing panels will generate the most energy, west-facing panels generate the most energy when demand is highest. That’s why some big proponents, including the California Energy Commission, encourage builders to include some west-facing solar panels in their developments.

In the end, south is best, but west and east are also good; having panels facing south and west will help you generate energy throughout the day.

Size

Along with orientation, the size of your roof will determine how many solar panels you can install. The average US home solar system size is 5 kilowatts or 12-13 panels with a rating of 400 Watts. With solar panels requiring about 15 square feet each, you need about 200 square feet of (south- or west-facing) roof space to fit 13 panels on your roof.

Shade

Big surprise: Solar panels only work when the sun is shining directly on them. If you’re surrounded by tall trees and your roof and yard are shaded most of the day, your choices are limited to either:

• Taking down trees
• Buying clean energy from a community solar system instead
• Opting for a clean energy mix from your utility (if available)

It’s important to note that shading doesn’t always come from trees and outside objects — sometimes roofs can shade themselves. The best roof design for solar panels is one with minimal tiers and overhangs that could cause shading.

Material

What is your roof made of? The most common type of roofing material is asphalt shingles, but solar installers can put panels on just about any of the most common types of roofing materials, including tile, metal, slate and even wood shingle.

Some roof types are more difficult to install on than others, and if your roof is made of trickier materials it may add to the cost of your solar installation.

Age

More important than the roof type you have is how old your roof is. According to a study by the National Home Builders Association, an asphalt shingle roof should last for around 20 years, while slate, copper, tile, and metal roofs can last 50 years or more. Meanwhile, most home solar systems are guaranteed to last for 25 years, and will likely last much longer.

So if your roof will need to be replaced in the next 10 years or less, consider doing so before your solar panels are installed. You can always replace the roof after your panels are in place, but it involves removing the panels and racks, replacing the roof, and then re-installing the panels, which adds more cost to the project.

Pitch

The slope of your roof isn’t as important as the orientation, but it can affect your solar energy output. The ideal roof angle for power generation is about 30 degrees, but roofs that are too steep make installation difficult, while flat roofs mean that you can set the panels at just the right angle, but you’ll be paying extra for the required racking.

As a rule of thumb, your panels should be tilted at about the degrees as your latitude. So if you live in Los Angeles at 34 degrees north, then your panels should face south and be tilted about 34 degrees.

Related Reading: How To Choose Solar Panels for Your Home

What if I don’t have the best roof design for solar panels?

Not everybody has a large, unshaded, south-facing roof. So what happens if your roof design is less than perfect for solar panels?

In these scenarios, there are two ways to increase your solar output:

Use panels with a higher power rating – Solar panels are rated from 250 to 450 based on how many Watts of DC electricity they can produce per hour. So, if you don’t have enough space for 16 250W panels, then you can achieve the same output with 10 400W panels.

Increase the number of panels – If you have limited sun exposure due to shading, pitch, orientation, or location you can simply add more panels. For example, Los Angeles averages around 6 peak sun hours per day while New York City averages around 4.5. That means it would require 15 panels to achieve 27,000 kWh per day in New York City, and around 11 panels to achieve 27,000 kWh per day in Los Angeles.

In both cases, you can expect your project to cost a little more than if you had a perfect roof for solar. However, the solar panels themselves make up a small fraction of your project cost, and adding or upgrading will have little effect on your energy cost savings over 25+ years.

Bottom line: There is no perfect roof

Although it’s tempting to want the best roof design for solar panels, solar panels are extremely versatile and can provide energy cost savings and clean energy in many applications.

Between the falling costs of solar equipment and the 30% federal solar tax credit, there’s never been a better time to go solar. Get started by comparing multiple quotes from vetted local installers.

Best roof design for solar panels FAQs

What type of roof is best for solar panels?

A south-facing composite asphalt shingle roof with plenty of space is typically considered the best roof design for solar panels. However, solar systems can be very versatile and provide clean energy and cost savings in a wide variety of applications.

What is the best roof design for solar?

It may sound simple, but a large square roof with a standard pitch between 20-30 degrees is ideal for a simple solar system. Roofs with lots of tiers with little extended space can create challenges for designers and installers.

What type of roof is not good for solar panels?

We hate to be the bearer of bad news, but if you have a slate or wood roof, your options are limited. Many solar companies will refuse to install on these materials, which can limit your options.

Some work-arounds include re-roofing with a new material or installing the system on the ground.

What if my roof is old?

Most roofs must be replaced at some point, but you have a couple options when assessing your roofs current state before going solar. If your roof is too old, some solar installers will replace your roof as part of the same project, which can help you save by combining the projects.

If your roof is getting old but not quite at point of replacing, it may be worthwhile to install the solar panels knowing you’ll need a roof replacement at some point down the road. In this case, re-roofing requires the added cost of having your solar company un-install and re-install the panels.

Solar panels can help aid the longevity of your roof, because they help protect against a lot of nature’s elements.

Will my roof have issues with leaks?

Leaks after solar installation are extremely rare. Yet, if they do happen it’s important to be covered by a warranty. Good installers offer extended warranties on workmanship, which means you won’t have to worry about being on the hook for any issues that could arise during an install.

If your roof seems like a fit, use Solar.com to receive free, no-obligation bids on a solar installation for your home.

One of the first questions you’ll be asked in the process of going solar is, “What is your roof made of?”

Solar can be installed on just about any roof type. However, there are certain materials on which solar panels can’t — or shouldn’t — be installed. So that begs the question, what’s the best roof material for solar panels?

In this article, we’ll review five different materials to see which one makes the best roof for solar panels.

Best roof materials for solar

Composite shingles

This is the most common, and perhaps best, roof material on which to install solar panels. Because composite shingles are so common, this roof type offers the widest range of options for equipment and installers. This reduces the need for specialized solar equipment and labor, and reduce your overall project costs.

Pictured on the far left in the feature image above, composite shingles — aka asphalt shingles — are made from a fiberglass or cellulose mat. Asphalt and other minerals are then added to the shingle to produce the final product.

Composite shingles are often the most affordable roofing type and come in many colors. Most come with a standard 30-year warranty, although they should only be expected to last 15-25, depending on conditions and care.

If your composite roof is older than 15 years or starting to show major signs of wear, solar installers will likely recommend re-shingling before installing solar panels. Even so, composite shingles are often considered the best material on which to install solar panels.

Related Reading: How To Choose Solar Panels for Your Home

Tile

Tile roofing is another very common roof type in the Western US that can be found in almost any neighborhood. Tiles, themselves, can be made of different materials, and that is why it is important to accurately determine what materials your tiles are made out of before proceeding.

Roof tile materials include:

• Clay
• Ceramic
• Metal
• Synthetic cedar
• Slate
• Concrete

The material type can impact the cost of your solar project. For example, installing solar panels on clay tiles may be more expensive than installing on concrete tiles.

When a solar panel array is installed on a tile roof, they will need to be attached to brackets that will lift the panels above the roof. The distance that the panels must be raised will be dependent on the material itself, and the cost is also affected based on what material the tiles are.

Most installers, especially in warmer climates, are familiar with and comfortable working on tile roofs. However, it may be harder to find an installer to work on a tile roof in the northern parts of the US where they are less common.

Here’s how a solar system looks on a tile roof:

Metal Standing Seam

Metal roofing with standing seams is one of the best roof material for the installation of solar panels. The standing seams on these roofs make the attachment of the panel array incredibly easy, and with easier installation comes a cheaper cost.

You also do not have to drill any holes into your roof with this roof type. Some of the other benefits of metal roofing are that, by itself, it is already more eco-friendly. They are often made out of recycled materials and are durable enough to last for over 30 years.

Metal roofs with standing seams can allow you to install both thin film and standard PV panels. These roof types also reflect a significant amount of sunlight where it is not being absorbed by the solar panel, which leads to a cooling effect that can increase the efficiency of your system.

Tar and Gravel

For homes that have a flat roof, it is very likely that they will be of the tar and gravel roof type (second from the right in the feature image). Tar and gravel roofs are made out of layers of sheets that are attached with hot tar and roofing felt. There are some other mineral coatings added, as well. Because these are flat rooftops, they may require additional brackets that can be tilted at the 30-degree angle.

This is very simple to do, but it will be more expensive than installing on a tilted roof or with a different material. Nevertheless, tar and gravel is still a very viable roof material for the installation of solar panels.

Wood

The last roof type that you will see commonly throughout neighborhoods are wooden roofs. Wooden roof types can include shingles at an angle or may be completely flat, so the specifics will be dependent on the way the roof is structured.

In any case, a wooden roof is not viable for solar panels because of fire safety concerns. Therefore, wood is not the best material for solar panels.

The best materials for solar panels

Rooftop solar equipment and installers have come a long way in recent years and most roof materials are suitable for solar panels.

With that said, the best roof material is anything that will keep your solar panels secure for their 25-warrantied life or longer. While there may be minor advantages for one material over another, don’t let perfect be the enemy of good. The important thing is to get a system installed so you can start saving money and generating clean energy.

All Things Roof FAQ’s

What is an ideal roof for solar panels?

In most cases a composite asphalt shingle roof, facing south with enough space for placement of your entire system would be the best. Although, in most parts of the country as long as you have space on your roof and you get ample sunlight, solar is viable on most roof types except wood shake. 

What is the best roof design for solar?

The answer is pretty straightforward, a large square roof is ideal for a simple solar system install. Roofs with lots of tiers, chimneys, skylights, pipes, and very little extended spaces, create lots of challenges for system design and installation.

What type of roof is not good for solar panels?

We hate to be the bearer of bad news, but if you have a wood roof your options are limited. These roofs will disqualify you from installers, although you still have the option to reroof or look into ground mount solar installations.

What if my roof is old?

If your roof is too old or worn down, it’s best to replace it before installing solar panels. Some installers offer both services, which can bring down the cost by combining the projects.

If your roof is older, but not at the stage of replacement, you can still install the system. However, you’ll likely end up paying for the labor to un-install and re-install the system when you do end up replacing the roof. This cost isn’t typically welcome when you’re already paying for a new roof.