Effects of Colors of Insulation

[Trooper]

The consensus seems to favor darker colors for quilt interiors; the theory being that darker colors absorb more energy and will make the quilt warmer. On the opposite end of the spectrum, the space blanket is designed to reflect radiant energy to keep you warm. I have read some posts where people wanted to use the dark color on the exterior of the quilt, theorizing that the darker color will absorb more (or reflect less) energy from the sun, creating a warmer quilt. Of course, this will work best if you sleep during the day, without a tarp, and in the warm sun.

I theorize that a black exterior and white interior would be best, but only a marginal increase in warmth, if any, would be realized. This is because there simply isn't enough energy in the environment at night to be absorbed by the exterior color, and most of the energy from your body would need to conduct into the insulation. By my theory, because we are nocturnal and under shelter, color doesn't really matter.

So, does anyone have any experience with thermodynamics that can help me understand this?


Moderators: I couldn't determine if this topic was most appropriate in bottom or top insulation. Please move or delete so that I am in compliance.

[warbonnetguy]

well, the outside of the quilt might be more likely to get wet (condensation, fog ect), so black on the outside would facilitate better field drying in the sun perhaps.

[Trooper]

well, the outside of the quilt might be more likely to get wet (condensation, fog ect), so black on the outside would facilitate better field drying in the sun perhaps.

The black would absolutely facilitate faster drying in the sun. I hadn't even considered other reasons for dark/light yet.

[Just Jeff]

I'm not convinced that shell color makes any appreciable difference in actual warmth. I know what the theory says...but that's mainly based on darker materials absorbing the sun's energy. Not sure about y'all, but I'm usually in my insulation when the sun ain't gonna help much.

Second, darker colors ABSORB heat...meaning they also absorb YOUR heat. So if you have a dark inner shell, in theory it will absorb your heat rather than reflecting it back to you like a silver shell would. Personally, I'd rather my quilt reflect the heat back to me as much as possible, rather than absorbing it.

Third, because of emissivity (as I understand it, at least), a black shell will give off heat just as it absorbs heat b/c it's about ability to move heat rather than ability to store heat...similar to how some materials are better conductors of electricity. So a dark inner shell will absorb your body heat easier, the heat will pass thru, then a dark outer shell will release more of that heat to the environment.

Using that logic, I guess it would be better to have both shells white or silver. Except that one black liner would make it dry quicker in the sun.

But as I said, I'm not sure there's actually enough difference to make base your shell color decision on these factors...especially if you sleep at night. I'd rather pick a stealthy color...JMHO.

[lazy river road]

Just Jeff, As I understand a baffled TQ works, the down lofts up, when you let off heat the heat is then stored in the down and that is what keeps you warm, The more down/higher baffels the warmer you are, on that theory if you used a darker inner color to draw heat away from you and into the baffels you would then want a light outer to keep the heat in. based on your theory wouldent that produce the most heat. This is in fact if the theory of your body heat and the color of the quilt actually matter or if the sun is needed to make a real difference. I am still new at this so I may be totally off or missing something. Their is so much to learn when it comes to down,

[Trooper]

But as I said, I'm not sure there's actually enough difference to make base your shell color decision on these factors...especially if you sleep at night. I'd rather pick a stealthy color...JMHO.

I agree that this is mainly an academic consideration, and I would prefer the natural toned colors for concealment. But, many people still make their quilts using this logic, so I am curious if the theory is sound.

You mentioned a white interior to reflect heat given off by the body. Is the color reflecting the energy or is it the material? Is there a difference in the energy from light and heat energy from a human body?

[lazy river road]

another consideration would be, how would a base layer effect this as well?

[Just Jeff]

...if you used a darker inner color to draw heat away from you...

The down clusters create small microclimes that keep the heat from moving quickly away from you...their function isn't to store your heat so much as it is to slow it's departure from you. It tries to stop the convection, and it's a poor conductor, which makes it a good insulator for our purposes.

But colors deal with radiation...which illustrates the problem with your logic in this case (said respectfully, not sarcastically or spitefully ), and the part I quoted above. You DON'T WANT anything to draw the heat away from you in the first place. You want the heat to stay in your body. Lighter colors will be better at keeping your heat near your body in the first place.

Put more simply, you want to store your heat inside your body, not inside your insulation.

You mentioned a white interior to reflect heat given off by the body. Is the color reflecting the energy or is it the material? Is there a difference in the energy from light and heat energy from a human body?

I think it's both, but it has to do with how much it reflects vs absorbs (emissivity). Given the same material (1.1 oz nylon), a lighter color will reflect more heat back to the body. But a mylar space blanket is more reflective than nylon, so it will reflect more heat than silver/gray nylon. Plus it's a vapor barrier so, used correctly, it can also stop evaporative heat loss.

Re: the energy difference, I'm not a physicist (so hopefully someone smarter than me can jump in to correct any mistakes), but at the basic level all energy just a different frequency/wavelength of wave, and the power is a function of wave amplitude. I think (off the top of my head w/o looking it up) that black material is absorbing the sun's IR energy, which is what heats it up, and that heat is what makes it dry faster. And re: the color of our insulation, it's the same...the shell is absorbing/reflecting the IR energy that our body is radiating. BUT our insulation also stops convection and conduction, which makes more of a difference in this case than radiation loss or the color of the shell.

Anyone out there have a better explanation?

[warbonnetguy]

the insulation itself is white, so wouldn't that give you reflective qualities even if your ripstop doesn't?

i really don't think there's any "real"(measurable) value other than dark colors being better for field drying.

hypothetically speaking, if the inner shell is black and absorbs more heat, isn't all that's happening is that you're warming up your insulation? that doesn't sound so bad. the heat holding ability of the down should remain unchanged shouldn't it?

[warbonnetguy]

if this has any measurable difference, then shouldn't a white long-sleeve t-shirt keep me warmer than a black one (in the dark). i don't buy it.