TOPIC: Energy Efficiency
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I am about to replace my Decra roof. It currently has a lighter grey color and my wife and I both like the black shingle color but living in DFW, Texas, we are concerned it will increase the heat in our attic during the sunlight hours. I can't seem to locate the answer on the impact of color choice for the stone coated metal roof. Being a larger 2 story home, my roof stays in direct sunlight most of the day.
We have been told there is minimal impact and I understand that ventilation also plays a large role, but when comparing the same ventilation structure, does the darker colors increase heat within the attic and if so, is there a an estimate of what the impact difference may be?
I would suggest checking with Decra but chances are the current roof has solar reflectivity in the 20% range and the new roof will be more around 5%. Just my guess based on some assumptions. You will steel benefit from whatever attic ventilation you have (perhaps see if it can be increased) as well as by the thermal break created by the airspace between the metal shingles and your roof deck. I really would not expect a huge drop in energy efficiency. There will be some drop but I have no way to quantify it. I am sorry.
We are trying to decide between Dark Bronze and the Dark Charcoal Grey. The emissivity and reflectivity is approximately the same for both. In regards to fading, which one fades more or least between these two colors? Thanks in advance.
The lighter color would, in theory, be less prone to fading.
I'm confused. Does an unpainted metal roof reflect or absorb heat/sunlight? Would painting it a white, elastomeric (?) "cool" paint" make my house cooler?
I have a corrugated metal roof, unpainted. The top floor of the house can really heat up in the summer, but I did not think it was because of the roof. I thought the roof, reflecting so much sunlight, already keeps my house cooler than not. No? Before I put on solar panels, someone said I should paint the roof with "cool metal roof paint" first, and so avoid installing air conditioning. Is that right?
--anticipating heat waves in Los Angeles, re. global warming. I would like to make a decision about Paint or Not.
Thanks for any help.
What is the construction of the home/roof assembly?
Warm air is less dense that cooler air so every house is going to be warmer upstairs in the summer. Just depends on where the heat is coming from is all.
Thanks for giving the source about reflective substance.
I am in the process on replacing a 20+ year old asphalt shingle roof on my home. Will any metal roof regardless of the color be more energy efficient that what I currently have, just because its metal vs. asphalt? I am selecting between the Sierra Tan (R35, E.91, SRI 39.1) and Sandstone (R51, E.9, SRI 59.8). The Sierra Tan will look much nicer with my light moss green siding and tan gutters and trim. I would like to understand just how much of a energy efficiency difference there is between the SRI 39.1 and 59.8? I want to make the most "green" option I can but I'm not crazy about the lighter color. Can someone help me understand just how big of a difference there is between what I have (old cheep asphalt) and my two metal color choices? Does it really make that bit of a difference between the lighter tan vs. the darker?
Your current shingles probably have an SRI of under 10. The Energy Star requirement is 25. Personally, I'd choose the color you like best. Thanks so much for considering metal!
I am installing new solar panels with a 30% gain from roof reflectivity. Over time...galvalume or white most reflective?
Gerald, The Galvalume will eventually weather, which will dull the "shine". This will reduce the reflectivity. The reflectivity of a high quality paint, can be affected by dust but that can be washed off, to return the luster to the painted surface.
The white painted should preform better, longer.
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