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Question DetailsAsked on 6/21/2016

Question: Does the black CertainTeed Landmark Designer shingles conduct more heat than the Grey?

Hi guys, I'm getting a home built brand new and I'm wondering if I should get the black or the Grey CertainTeed Landmark Designer shingles. I have to stick to that brand, but I can pick any color. I'm in the greater Tampa area so it does get rather not, especially in the summer. So as of now I chose the Grey shingles, but I really love the contrast of the black with our (Grey and white) house.

So, what I'd like to know is did I make the right decision? Should I change it? How much of a difference is there between the two? Thanks!

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5 Answers

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Edit: I should mention that what I'm talking about here is in home temperature, not attic.

Answered 2 years ago by Badonk

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Here is a link to their fact sheet -


http://www.certainteed.com/resources/...


Note that "Designer" is a series, not a specific shingle - so be sure when talking to the contractor/writing upo the scoipe of work, that the particular "model" you want is specified.


Typically, gray will have greater reflection of the solar heating, and will have a lower solar energy uptake in the daytime - though will also cool off a bit slower in the nighttime than a "blackbody" black shingle - but check out the table in the link for the different colors.


Realistically, if the shingles are solar reflective granule design, there will not be a great difference in black and a darkish gray - you have to get to a light gray, sometimes near off-white, for there to be a dramatic difference in solar heating.


However, in your area - I definitely would not go with black unless you happen to have a thermally isolated "double roof" - a rarity, as it costs quite a bit more to put on the extra spacers and air gapping and typically double sheathing of a "double roof", which has a continuous airflow under the shingled surface and the sheathing forming the "ceiling" in the attic. In any normal roof situation, black shingles are an invitation to added air conditioning cost in the cooling season, and to roof icing in snowy areas in the winter (though they can be useful along eaves to reduce ice damming).


BTW - if near/under trees, the gray will show tree staining a lot more. Conversely, black will show bird droppings a lot more, and generally shows dirt more than anything but a quite light gray or white.

Answered 2 years ago by LCD

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In rereading my answer after it posted, I saw I did not exactly answer your question as asked.


Simplistically but for all practical purposes for you there are several factors affecting heat - the albedo or reflectivity or reflectance of the roof material (how much of the solar energy it reflects back), the emissivity (how much of its heat it re-radiates to the sky as infrared energy), and the heat capacity and conductivity - how much heat it can hold and how fast it dissipates that to the in-contact underlying material - in this case the attic roof sheathing.


You asked about conductivity - basically, all shingles of a given type of material will conduct heat to the house at about the same rate because they are made of the same materials - just a different surface color. To reduce conductivity, you generally go with an underlying insulation layer if that is a major factor - normally only done with flat roofs because shingles over significant insulation require god-awful long nails, so excess roof heat issues are normally (with a ventilated attic) handled with ridge vents (on significantly sloping roofs) or ventilators (on flat roofs) to remove much of the heat buildup in the attic, then insulation on the attic floor to limit heat transfer into the house (and out in the winter).


IF you have an unfinished attic, ventilating it (ridge vents most effective if enough slope to keep them from taking in rain water - typically 3:12 or steeper roofs) is by far a better way to handle attic heat than worring about difference in shingle types (unless going with a double-layer or insulated sheathing roof, which is normally only done at new construction time). The most effective and cheapest means of limiting heat transfer between house and attic or vice-versa is insulation on the attic floor, provided moisture control and removal is properly considered in doing so.


Heat capacity - how much heat or energy it will hold in the shingle - is going to be very similar amongst different roof materials - so not something that is considered in normal design and most manufacturers don't even report it because there is little you can do about it - a roof absorbs heat, and because of the heat capacity stays hot after the sunlight starts dropping off, resulting in continued heating of the house from the roof into the evening - typically for a few hours to a noticeable extent. That is commonly why (along with poorly ventilated attics) a house can feel unduly warm in the late afternoon/ evening even though it cools off rapidly outside - the time of day many people turn off the A/C and open the windows to remove the heat being conducted in from the roof and siding,


More to the point for your question is the reflectivity - how much of the incident solar energy is reflected back and not absorbed at all, and to a much lesser extent the emissivity. High reflectivity (high albedo) reduces the amount of energy that goes into the shingles in the first place, and is therefore available to heat the attic. Obviously, metallic silver (like on many trailer homes) or some state-of-the-art glass or multi-layer reflective coating reflects the most, followed by white, then gray, then lighter colors, then the dark colors, with dark browns and black absorbing the most solar energy - almost all of it. A polished silver or aluminum foil, for instance (when clean) may reflect into the high 90% range - up to 98% when perfectly clean, a specially coated silver-colored solar reflective granule design maybe in the high 80's, a solar coated white typically in the low 30's to high 20%'s, a normal light gray or white maybe in the mid to low 20%'s, and very dark shingles and black may reflect only 3-8% of the incident energy. So clearly going with a light colored shingle gets rid of much of the possible solar energy available to heat your roof. However - because of re-radiation from the roof (emissivity) and convective cooling (the shingles heating the air touching them and the hot air rising away the roof) the net result is that the most reflective shingles generally only run about 10-20 degrees surface temperature cooler than the dark ones - so perhaps 130-140 or so versus 150-160 on a hot sunny day (though up to 200 degrees on pure black roofs like built-up tar). Your inside temp say is 70 degrees, so you are looking at perhaps a temperature differential (which is what drives heat through materials) of maybe 70 versus 80 or 85 degrees between a very reflective roof and a dark one - or about 10% to maximum 20% difference in the heat being conducted into the house from the attic. Considering the other heat sources (walls, windows etc) you might therefore see a few percent to maybe as much as 5% difference in interior A/C energy use with a dark roof over a light one. So, while the hotter attic and roofing materials will likely result in somewhat faster aging of them (though not dramatic), the difference in your energy use and the amount of heat coming from the atticbetween dark and light shingles is not likely to be highly noticeable, if at all. With a poorly ventilated attic, or one without ventilation at all however, that factor can make a much larger difference - again, the reason most trailer homes (where the roof is also the inside ceiling) have bare metal roofs - highly reflective, so less solar heating (and incidentally less winter heat loss too because of usually significantly lower emissivity).


One other factor on the color - even with high-reflectivity or solar saving shingles, they fairly quickly approach ordinary shingle conditions as they accumulate dust, so no matter what color you go with you will eventually end up with something that is quite non-reflective - so I would say go with the color you want.


Emissivity measures the re-radiation of heat from the shingle back to the sky and is related to the differential of tempearatures between the emitting material and the surface or area it is emitting towards - in this case, from the shingle to the sky. Because this happen continuously during the day it rapidly achieves a steady-state condition during daylight and makes little or no difference in practical terms - higher emissivity does result in more rapid roof cooling in the evening/night as the solar heating drops off so dark roofs actually tend to cool faster than light colored ones, but for practical purposes with normal roofing materials because lighter roofs run cooler and because differences in emissivity are not likely to be substantial between products or colors unless bare metal coated - usually on the order of about 80-91% that of a true "black body", you are not likely to notice the difference UNLESS you have attic rooms - in which case the ligther the shingle the better in hot climates, because every bit of added heat is generally noticed in hot areas.


One caveat on the color choice - IF your air conditioner or A/C ducts which are not well insulated are in the attic, then a darker shingle will result in a hotter attic by maybe 10-30 degrees or so, so your A/C efficiency will be lower and the opearating cost higher, so in that case I would recommend a light color. Of course, A/C systems and ducting should not be in the attic anyway because ti really cuts into the operating efficiency, but there are a lot of builders out there trying to squeeze every inch out of a house, and some homeowner's associations do not allow outdoor A/C units, so you get what you pay for.

Answered 2 years ago by LCD

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Thank you sir, really appreciate the quick response! The builder is pioneer homes and I've seen the a/c units out back so I think that's a non-issue. I think I'll call them back up and switch to black. Thank you so much, I'm a graphic designer so the roof not matching was going to annoy me so much lol

Answered 2 years ago by Badonk

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Yeah - I can see how that would disturb and nag on a designer type like you or an architect or interior designer or such - I would say go for the color scheme you like, then if you find the attic is putting too much heat into the house you can lataer consider (fairly cheaply, especially if a DIY'er) adding insulation on the attic floor to reduce the heat conduction to the house.


Definitely, if a normal slope peaked roof 3:12 or more say - meaning 3" rise in 12 inches of horizontal run, or a 25% slope) or steeper - definitely make sure ridge venting with matching adequate eave/soffit ventilation intake area (insect screened) is included in the deal - most likely required by code in your area. If flatter roof then you would need opther type of ventilation, but also shouldnot be using shingles on less than a 3:12 or 4:12 roof.


In your area - I would also strongly recommend insect screening under the ridge vent slot unless the ridge vents being used incorporate bug screening in them - very few do. You do not want palmetto bugs and termites and such getting into your attic through the ridge vent, which unfortunately a lot of brands do. I insect screening is put in at the ridge vent slot in the sheathing, it should be inspected periodically for blockage with tree seeds or the like which might blow in through the ridge vent - maybe every year or two at first to see if an issue in your area, then as needed after that. usually a bigger problem in birch and oak and cottonwood country where masses of seeds blow around and plug up intakes - don't know about Florida sources for stuff like that other than maybe blowing sand. IF the screening does start blocking up, usually pretty easy (unless masses of seeds) to blow it back out with a leaf blower from inside the attic.


One other thing on the shingles - make sure the model they are proposing meets your local hurricane code for blowoff resistance - mandatory by code in most of Florida so they should, but one of many ways unscrupulous builders cut costs behind a buyer's back.

Answered 2 years ago by LCD




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