Today we are catching up with Tad Carter, Sales Director and Technician for Solaroo Energy, a local Utah Solar Installer, to discuss how different roof types and exposure can affect solar energy production. After all, every roof is different, and there are some key factors regarding roof orientation, tilt, shingle type and age that can be the difference of saving tens of thousands on your system, or not saving at all. We asked Mr. Carter to describe some of these factors for us to consider.
The order of the best producing directions for your solar panels to face is as follows:
First Place – South. South is the highest producing because the sun shines in the southern sky for most of the year. And more sun equals more production.
Second Place – East. Really? East? There are a couple variables, but yes, East might be inferior to the West in the NBA, but not with solar in our climate. One common misconception is, “the west side of my house gets so hot, it has to produce more than the east.” But, heat does not equal production, sunshine does. In fact, most solar panels operate more efficiently in cooler temperatures than in hotter temps. West will also have more clouds on average than East, mainly for the fact that afternoon thundershowers in the summer are more prevalent. Therefore the East (morning) is generally more productive than the West (afternoon).
Third Place – West. OK, let me stick up for West a little. West is not much behind East as is, and it can move into second place if you consider snow melt, or if you live on the east bench next to the mountains. East is not very productive when the sun is stuck behind the Wasatch Mountains until 10:00am.
Last Place – North. We should almost say “No Place”, because north facing roofs won’t even qualify for the tax rebates.
Other factors can play into which sections of roof are the best to install panels, such as: trees, chimneys, roof vents, and other shading issues.
The tilt or pitch of your roof will determine how much summer sun (directly above you) you will get, and how much winter sun (low at an angle) you will get.
The most efficient angle in the dead of the summer for where the path of the sun is over Salt Lake City, is roughly 16 degrees, which is between 3/12 and 4/12 pitch. The most efficient angle for the dead of the winter is roughly 64 degrees, which is really steep (roughly 24/12 pitch). If you average each month of the year, and weight the summer heavier since we have more sunlight in the summer, a good angle would be between 28– 35 degrees (roughly a 6 or 7/12 pitch). If you are steeper or flatter than this, it does not mean solar won’t make sense, it just means you’ll be more efficient at different times of the year.
Shingle Type and Age
When talking about shingle type, the concern isn’t really about production, it’s about installation. Asphalt and aluminum shingles are relatively easy to install solar to. Tile shingles and corrugated metal roofing are more difficult. But production won’t be materially different based on your type of roofing.
Age brings up two concerns: First, if you need a new roof next year, you’ll probably want to do that roof first, then install solar. It is expensive to remove a system and reinstall. Second, If your home is older and doesn’t have trusses, there could be some structural braces that will need to be installed to your rafters to be able to support the weight of your system. Most of the time those structural modifications aren’t expensive, but they will need to be made. Keep in mind that your roof and structural upgrades can be eligible for the federal tax credit, which can further help your solar investment.
Mr. Carter comments, “Whatever your roof exposure is, we recommend having a SunEye test done to determine the available sun on your roof for each season. We will do that test at no cost for people who want to see what their roof will produce.”
For more information about solar, or to see how much energy your roof will produce, go to solarooenergy.com.