One of the most overlooked decisions when buying a solar program for your home, is what roofing program is the best fit. With the expense of solar being high enough, most homeowners do not have the budget to be concerned with what roof they put those solar panels over top of. But, what if you are going to change your roof at the same time you add solar, or the idea is to eventually install solar later, down the road?
Here are the three majorthings to consider when making that decision.
Solar electricity is expensive to generate. What I mean by that is, the solar systems total cost must be amortized over time, to justify the value of the electricity it generates. The more energy inefficient your home is, the more of the electricity you generated is wasted. So conversely, the more energy efficient your home is, the further your generated electricity goes. Steps like more or improved insulation, and low E glass for windows make sense, if you also have solar.
Asphalt roofs are comprised primarily of asphalt petroleum, rock granules and a fiberglass mat base. These are all heat retaining materials because they have a high thermal mass. Metal roofs, on the other hand, handle heat much better. They are highly emissive, meaning the heat they gain is easily dissipated through a light breeze or some form of shade and the sun setting. The right metal roof will be painted in a reflective ceramic based paint. These paints called PVDF’s, more often referred to by their brand name Kynar, are formulated to reflect the infrared portion of light energy that hits the roof. This is the portion of light that carries heat of the sun’s energy. Even a dark colored metal roof, that is Kynar painted, is energy efficient and Energy Star rated.
The right metal roof has 67% less heat gain than the average asphalt roof. That equates to 25% less energy consumption, during warm months (the biggest sun days), just by swapping an asphalt roof for the right metal roof. So, if you reduce your energy costs by 25%, you just made your solar generated electricity go that much further, that's a huge PLUS!
I find that homeowners rarely think about how long their solar panels will last, when compared to the life expectancy of the roof they are installed over. Currently, most solar panels being manufactured are designed to generate at a stable level of output for 25-30 years or more. In fact, most of the panel output ratings are based on their performance during that 25-year window. (This is why many homeowners see their systems outperform the manufacturers output rating, right after install.)
It is great that they last so long, but, there can be a hidden issue. According to the National Asphalt Shingle Manufacturers Association, the average life of an asphalt roof is 17 years. In Texas, it is even less than that. This means that at some point during the usable years of your solar array, you will be forced to change your roof. That means pulling all the panels down, removing all the mounts, electrical wire masthead, and conduit. Then, reapply it all over again, after the replacement roof is finished. That is, both a huge hassle and expense, that can be avoided, not to mention all the lost captured electricity.
How the solar system is mounted is also a common overlooked step. Typically, stanchions or mounts arescrewed through the asphalt shingles that the panels are mounted on top of. They need to have an air gap between the panel and the roof, so, that thepanels do not overheat and operate correctly. These stanchions are potentialleak points, and when they do leak, who do you call? The contractor who put themounts on, or the roofer who installed the roof?
One of our Mechanically Fastened Standing Seam Roofs, with a 1.5” seam height, makes for the perfect mount of your solar array. All solar panels are designed to mount on a device called an S-5 Clamp. It is a metal block with a slot that sits over the metal roofing panel seam, and a screw that tightens into the wall of the seam. Then, the solar panel screws directly into the top of the mounting clip. This means two especially important things. One, the set screw DOES NOT make a hole in your roof, so you eliminate potential leaks. And two, the panels can be removedor reset on those same clips for servicing, panel upgrades or any other reasonto move them.
Optimal panel temperature almost never gets discussed regarding roofing choice. Solar panels are manufactured to operate within a temperature window, having a minimum low, as well as an elevated temperature. It is quite common for asphalt roof heat levels of Texas roofscapes to be above the optimal temperature for a solar panel. Remember all the things that were discussed about energy efficiency earlier in the article? They apply here, as well. Even a dark color of a Kynar painted roof, can keep your solar panel in its best window to generate maximum electricity.
I know this may be a lot to take in, but, combining your solar with the right roof choice is a HUGE deal, when it comes to your home. We must get it right the first time. Thanks for the read, and if you have any questions, please do not hesitate to ask. And, if you would like a free consultation about adding a metal roof to your solar powered home, fill out our contact form right here on the website.
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