How to Determine if Your Roof is Solar-Ready

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  • May 15, 2015
**This blog post was featured on KSL. In recent years, use of solar energy has become more and more prevalent in our society. The growing popularity of solar may have caused you to wonder whether or not your home receives the sunlight necessary to produce solar energy and if so, where on your roof would be the best place to position solar panels to produce maximum energy? We recently caught up with Solaroo Energy and Kelly Curtis, Director of Operations, to discuss how one’s roof can impact the decision to go solar. 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.

Roof Orientation

The order of the best producing directions for your solar panels to face is as follows: First choice – south South is the highest producing because the sun shines in the southern sky for the majority of the year. More sun equals more production. 25486729 Second choice – east Really? East? There are a couple variables, but yes, the East region 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 choice – west OK, it’s time to stick up for west a little as it is not far behind East after all and can very easily move into second place 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 10:00 a.m. Last choice – 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.

Roof tilts and angles

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). 25486730 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 work well with solar panel installation. Tile shingles and corrugated metal roofing are more difficult. But production won’t be materially different based on your type of roofing. 25444310 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.