Does anyone have experience with the Dow Powerhouse Solar Shingle?
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Can the Dow Powerhouse Solar Shingle be safely installed on an unvented cathedral ceiling/roof which is insulated below the deck with impermeable closed cell insulation. will this Dow system trap moisture and condensation below it? What about the Certainteed Solar system which is installed directly on the roofing deck? For solar PV systems with modules raised off the roofing deck, what is the long term effect of shading, moisture and fungus on these shingles? Do these shingles below the raised solar PV module have to be replaced before the life expectancy of the solar PV system?
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Replies
Joseph,
First of all, some of your questions were already answered (the last time you posted this question). Here is the link if you didn't read the answer the last time you posted:
https://www.greenbuildingadvisor.com/community/forum/green-products-and-materials/27512/does-anyone-have-experience-or-opinion-dow-powerh
Joseph,
If you have any questions about whether a photovoltaic roofing product can be installed on an unvented roof, the questions should be directed to the manufacturer of the photovoltaic roofing product.
Q. "For solar PV systems with modules raised off the roofing deck, what is the long term effect of shading, moisture and fungus on these shingles?"
A. I don't know why you think there will be fungus on shingles under PV modules. I haven't heard of fungus being a major problem on asphalt shingles. However, algae are fairly common on shingles. Most studies show than algae are an aesthetic issue, but that algae don't shorten the life of shingles.
If there is an air gap between the roofing and the PV modules, the PV array will reduce the exposure of the asphalt shingles to rain and sun. By doing so, the PV array will lengthen, not shorten, the lifespan of the asphalt shingles that are shaded.
Q. "Do these shingles below the raised solar PV module have to be replaced before the life expectancy of the solar PV system?"
A. If you are talking about conventional crystalline PV modules with aluminum-and-glass frames, the answer is yes. The PV modules will last longer than the asphalt shingles.
Martin,
Thank You for your reply to my recent questions about solar PV systems. Please accept my apologies for needlessly repeating a question on the GPA, but I recently became a GPA PRO Member and was uncertain if recent questions were posted before my membership became effective.
Joe Poland
Joe,
Glad to help. And welcome to GBA Pro!