Does dark siding make for a hot house?
paula_builds
| Posted in General Questions on
Will a black/dark grey paint make my house hotter? The other big factor is that I’m planning a continuous layer of R5 insulation on top of the sheathing (and R23 between studs). Also I am planning on a rain screen (probably at least 1/4 inch). It seems like these two factors could make a difference in the dark paint NOT making my house hot?
The charcoal/black paint trend is tugging at me! Anyone have regrets after choosing dark paint? For this OR other reasons?
Thank you!
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Same question here ... 100 year old cladding with nail head rust showing through has us looking at darker paint colors.
Dark siding would absorb rather than reflect more sunlight, making the siding hotter. Dark would also make it more likely to radiate heat away from its surface. You might want to note where and when (and what season) that sunlight hits your home.
In order for sunlight to reach your siding, the sun must shine on it. Cloud cover, tree cover, shading from other buildings etc. would reduce sunlight heating your siding. On the north side of your home, almost no sunlight would strike the vertical siding, on any season of the year. However, on an unprotected west-facing side, you could have lots of sunlight striking your home in the afternoon. Same for the East side in the morning, but cooler AM temps would reduce the effects of heating. The south side would get little sunlight striking it directly during May through July, but more starting in August, when it possibly could become a problem outdoors near the exterior of that wall.
If you were outside the home near the home, you would notice the hotter temperature. However, note that for heat to reach the interior, it would migrate through a rain screen (about R-1 air gap), R-5 exterior insulation, R-23 wall insulation or R-7 studs, and drywall and interior air film. So most of the heat would dissipate into the exterior air rather than end up inside your home. The air film on the exterior of the home is a tiny fraction compared to the R-value between the siding and your home interior. The heat would radiate or air current convection could remove heat from the surface, much more than the tiny fraction of heat that would migrate through the well-insulated (and I assume airtight) wall. (Windows however would be a MUCH bigger problem with heating the interior.)
So you might not want an uncovered patio located right next to the westerly facing side of your home, especially if your home is located in a heat-dominated climate. You could use a porch roof, trellis, tree cover or other methods to reduce the sunlight striking your siding to make the exterior more comfortable in hot sunny weather.
With all the insulation and gaps you mentioned I don't think it will be an issue. I am installing black metal siding and I was wondering the same thing.
When the sun is most powerful, in the summer, its also very high in the sky. So a southern wall is less affected than one might imagine. While the roof might be baking, the siding is less so due to the less direct angle to the sun's rays.
But like Robert said, as the sun moves lower in the sky and toward the west the angle becomes more perpendicular to the vertical siding, heating it more.
If it was not highly insulated, this would be a big issue. With all of your insulation and air movement, not so much.
On the black siding trend, I will say it shows dirt and pollen very easily. I went with black window frames and some(not all) black siding. While I do not regret the choice I am seeing that to keep it looking crisp might require a bit more cleaning than if a lighter shade was chosen.
I find that since darker colors cause more heat/cool cycling, they tend to be harder on finishes, requiring more frequent repainting. Also, the darker colors tend to fade faster, or at least the fading is more noticeable. Of course these comments refer primarily to painted surfaces. Naturally dark (like the various charred finishes, etc.) materials may not be as affected.
Foil faced rigid insulation should alleviate any concerns. The foil facing, in conjunction with a rain screen gap, will retard heat radiating off the back side of the dark cladding.
Foil facing also acts as an excellent water/vapor barrier consequently, imo. it would be better to make the foil facing your WRB as well (flash windows to the foam rather than a WRB sandwiched between the foam and sheathing.
A lot of old historical homes were black or dark colors. So did they know something we don't....???
IMO..Darker colors were cheaper to make, paints weren't as free of impurities as they are today consequently maintenance was constant.
Wouldn't you say that today painting a house is perhaps once-a-decade proposition? Maybe ever 5 yrs?
Wouldn't you agree that the cost of paint today is insane....
Indeed.
Hi Paula,
I agree with most of the comments here that with your assembly, dark siding is unlikely to heat up your home in any significant way. However, there's a lot to know about how the color will effect the siding itself, included increased movement, color fading, etc. You may find this article helpful: Choosing Black Siding
>I agree with most of the comments here that with your assembly, dark siding is unlikely to heat up your home in any significant way.
+1!
In an insulated house, the solar gains though windows are a much bigger factor than direct heating through the walls. With good instrumentation it's probably possible to measure the difference of black finish compared to some other standard finish. It's easier to measure the difference in heat gain between a high solar reflective index finish and a standard finish, but even that isn't going to move the needle on equipment sizing or comfort in an R23 +R5 c.i. house.
Master of all things BTU,
Where have you been?
Paula,
The consensus appears to be that the dark colours won't appreciably affect the heat of the wall. However I'd caution against using any materials that you can't change the colour of later. I suspect the current architectural fashion for all black houses is going to be quite brief, and you don't want to be stuck with something you can't update.
I’d make sure the rainscreen is vented at the top AND the bottom to allow for convection. If you then use foil-faced polyiso and tape the seams with foil tape, you have a radiant barrier too. Those two things will minimize any additional heating from the darker siding, and you have enough insulation to prevent it from making any noticeable difference indoors. You shouldn’t have any issues with the darker colors. Note that if you have any PVC trim or details, those materials are often explicit that shouldn’t paint them dark colors so be warned.
And Dana, we had a thread a while ago wondering where you’ve been. Hope you’re ok.
Bill
We painted our house "Storm" (SW) blue, which is a very dark blue about 2 years ago. One side of the house gets direct afternoon sun from about 2:00pm til sunset. The dark blue paint made the siding so hot that it actually spewed out sap and the sap is now running down the siding in a couple of places. This siding is 128 year old pine. Just thought, I'd throw that out there as one of the unexpected consequences of the heat absorption into the old wood if that may apply to you.
Here is an advise I give my clients... Any time you make a house too custom, you'll drive away potential buyers if you need to sell. The same applies to trends, bold and/or flashy, are usually short lived..
All of the input was great, thanks everyone! The good thing about building slowly is that I can back away slowly from ideas that aren't so great.