Aside from being outside in the summer sun . . . does it matter whether you’re wearing a black t-shirt or a white one? Specifically, does it matter when you’re asleep, at night, when it’s hot, and no A/C?
If it’s hot and there’s no air-conditioning, why are you wearing a teeshirt at all?
But, no, if you do, perversely, wear a teeshirt I don’t think the colour will make any difference. Assuming you are in the dark, you are not being exposed to radiant heat, so the different reflective capacities of black and white teeshirts shouldn’t make any difference to you.
This is seeking a factual answer?
Depends on if the wife shoots fast and asks questions later.
Yes.
I’d go with whichever one is softest and most comfy for best sleep.
Or nothing at all if it’s quite warm.
Then I think UDS nailed it in one. Unless you’re sleeping under a sunlamp, the color won’t matter.
If you sleep in the dark, it has no color. Color is the spectrum of visible light that reflects from an object’s surface, and when there is no light, there is no color.
If you sleep in the dark how do you know if there are ninjas in the room or not?
C’mon, folks, we can make this waaaay more complicated. Consider this earlier thread:
Best color to paint a radiator
So we clearly have a number of factors to balance here. I will take the liberty of assuming that the sleeper is lying in a vacuum upon a flat surface under a clear night sky. Under these conditions, the emissivity of the shirt material does play a role, and a black shirt may be a more efficient radiator of infrared radiation, resulting in a different degree of cooling compared to a white t-shirt. If you pick the proper shirt material, you may even be able to cool the shirt to below ambient temperature (see Stanford press release here) This is done by ‘tuning’ the infrared wavelengths emitted by the material (by manipulating the thickness and composition of the various layers) to those that are not absorbed by the atmosphere. This is in the absence of incoming light. Inside a closed room, your increased infrared radiation may not amount to much.
Balance this against the insulating effect of having a shirt covering your skin and blocking evaporation, convection, and/or conduction. Is the air warmer than body core temperature? Is the humidity low or high? Sleeping naked on top of the covers would almost certainly trump whatever radiative differences there would be between black and white shirts. Coating yourself with a film of halfnium oxide and silver like the Stanford material similarly probably gets beaten by ye olde marke 1 swamp cooler effect of a film of sweat evaporating. And if you’re under the covers for some reason, radiation differences won’t matter anyway.