One of the first questions we often hear from people is: “Is my roof good for solar?”
Obviously, there’s no one good answer to this question. Everyone’s roof is a little bit different, from the material used to the orientation and pitch. Roof age and condition can also play into the feasibility of installing solar panels, and obstructions like chimneys can limit the number of panels that can fit up there.
In this blog, we’ll discuss what makes a roof good for solar.
Roofs can be made from a variety of materials. There’s the traditional asphalt shingle that we see all the time around here, as well as metal roofs. Businesses often have flat roofs that can be made from synthetic rubber or other materials.
Solar installers have no shortage of options for mounting hardware to match the roof type. Manufacturers have developed products to mount solar panels on seemingly any roof.
So no matter what your roof is made out of, chances are, someone makes the right part to install panels for you.
Orientation and pitch
As we’ve covered before, solar panels work best when they’re pointed directly at the sun. That means the angle the panels are tilted is going to affect their production.
The “optimum angle” for a solar panel is going to depend on the time of year. In the summer, the sun is higher in the sky. In the winter, it’s lower.
If we had to pick an optimum angle for Duluth, we could pick 32 degrees. That’s 15 degrees subtracted from our latitude of 47 degrees, as SolarReviews explains.
As for the azimuth, or compass direction, solar panels ideally face south in the northern hemisphere.
But obviously not every roof in the Northland faces directly south with a pitch of 32 degrees. That doesn’t mean solar is a dealbreaker. Even if your roof isn’t facing the “ideal” direction, it can still provide enough space for your solar panels to soak up the sun’s rays.
Another way to think about the original question — “is my roof good for solar?” — is that the best roof for solar is the one you have. It’s not like you can easily change the roof’s pitch or the direction it faces.
There are some things you can control, however.
Age and condition
Ensuring that your roof is in good condition and won’t need to be replaced anytime soon will save you a major headache down the line. If you have to replace your roof after installing a solar system, you’ll have to remove the panels and reattach them after the roof is replaced.
The type of roof will determine how long it will last. Traditional asphalt shingles can last 15 to 30 years, while some types of metal roofs can last 50 years or more, according to Forbes. A typical reroofing job costs between $5,600 and $12,000, according to HomeAdvisor.
If you know you’re going to need a roof replacement in the next few years, maybe it’s worth combining that project with a solar installation. That way, you’re avoiding the cost of taking down and reinstalling the panels.
One of the most important factors when considering a rooftop solar array has nothing to do with your roof: trees.
Nearby trees can create a lot of shade on your roof, which in turn will hamper your system’s production. It probably goes without saying, but as far as solar goes, living in a field is better than in the woods.
We can analyze how much energy you’d lose due to tree shade thanks to the software we use to craft proposals. We can also recommend any tree cutting or trimming you’d need to do to improve your production and get the most out of your investment.
This map from the University of Minnesota can also help you determine your roof’s solar suitability.
The size of your solar array is limited by several factors. That includes your roof’s square footage, local building codes and any obstructions getting in the way.
In Minnesota, solar installers have to leave three feet clear on both sides of the array for walkways. And depending on how many solar panels are on the roof, there must be at least 18 inches between the panels and the roof ridge.
Roofs often have vents that keep moisture and heat from building up in your attic. They may also have chimneys, satellite dishes and other protrusions that reduce the usable square footage of the roof.
In some cases, the homeowner may be able to rearrange or remove these obstructions. But something like a brick chimney isn’t going anywhere.
When you wonder, “is my roof good for solar?” remember that there’s no one good answer to that question. Not every roof is “ideal” for solar installations, and there are a litany of considerations for determining your home’s solar potential.
Meanwhile, we can always look at alternate options for installing solar at your home, whether that’s installing on a nearby garage or on the ground.
A qualified solar professional will be able to help you determine how many solar panels will fit on your roof and how much energy you’ll be able to produce. From there, it’s a matter of determining whether it’s a worthy investment for you.