Chili Technology has a neat gadget, a pad for your bed that warms or cools. (They also have a mattress that does the same thing.)
The low temperature is 46 degrees F and the high is 118.
But if you were sleeping on a surface that was maintaining a temperature of 46 degrees, wouldn’t you be at risk of hypothermia? Or do I not understand how hypothermia works?
My thought upon reading the thread title: At over 45 degrees, wouldn’t you slide off?
Maybe at low temperatures you stick to the bed.
Assuming you’re not passed out (drunk or on drugs) I would think that you would be way too uncomfortable shivering long before you actually got hypothermia.
Tthe most important factor in hypothermia is your core body temperature. Even a relatively small change in core temperature can cause hypothermia, but your body is both producing its own heat internally and insulating itself from the cold outside. So it’s more a matter of rate of heat transfer than of temperature itself.
Even if the pad is 46, I doubt it can make all the air around your body (especially under blankets) 46, so you’re going to have some warmer things around you. People can swim in water that cold for some period of time before they would start having problems from hypothermia, and water is going to conduct heat away a lot faster than air or a pad.
Ha! I didn’t think of the implications of my title. 
In the old days people slept in the cold. It was thought to be a good defense against TB.
Can you sleep when it’s 46ºF (8ºC)? I don’t think you’d die at that temp if you slept outside in it.
You also have to assume you are going to have clothes on and covers as well.
It reminds me of my friend who was all worried 'cause her cat liked to sleep on the dryer. I told her “It’s not dead, it’s asleep. If the cat can jump UP ON TO the drier, it can jump OFF the dryer.” It amazed me how hot my cat liked to get. We’d put on a fire and the cat would plop right down in front it. It was a tuxedo cat and the black part would get really hot, but if I picked the cat up and moved her, she’d give me an annoyed mew and move right back in front of the fire.
I remember trying to sleep on a waterbed where the water was not quite warm enough. That was nasty. It was probably warmer than 46F, too.
My first thought upon seeing the thread title was, “46 Celsius? Isn’t that a little warm?”
You can get hypothermia in 68° F water, but you don’'t get it in 68 degree room temperatures.
While a bed can cool to 46° F, you can clothe yourself, and maintain an air temperature that is comfortable.
You’ll take action to warm up long before hypothermia sets in. Hypothermia sets in when you pretty much have no choice or options to get warmed up.
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A whole bunch of cites claim that most hypothermia cases occur between 30F-50F, and I know there was a news story within the last two-three years about someone lost in the woods dying of hypothermia while it was in the 40s.
It all depends on what you’re used to.
My Dad talks about some of the houses he lived in as a child. He grew up in logging camps in northern Michigan. It gets cold up here. For at least a couple winters, his bed was on the enclosed, unheated porch. He said the cold never really bugged him - being enclosed and having blankets was just fine. It regularly gets below zero here at night.
:rolleyes:
The bed is 48°, but the person isn’t outside in 48° weather/water!
There’s a difference between sleeping in a normal bed in a cold room and sleeping in a refrigerated bed.
A normal bed will trap some of your body heat and thus prevent you from getting too cold, even if the temperature outside the bed is considerably lower, but if the bed itself is maintained at a lower temperature, and you’re in contact with it, then you’re going to get cold.
I notice the thing uses Peltier modules for heating and cooling - that means there will be a practical limit to the amount by which it can be heated or cooled above or below ambient temperature (despite whatever the dial says)
Extra clothing wouldn’t really help to warm you, your body weight pressing against the bed would diminish the insulating effect of the clothes.
Extra bedding wouldn’t help you because you wouldn’t be able to trap warm air under the bedding.
I’m sure the products won’t kill you, but “don’t fall asleep in the snow” has been a cautionary tale for ages
I wonder how well the bed deals with high humidity environments. Forty six degrees is easily cold enough to get condensation. Waking up to a cold, wet bed isn’t likely to be good for anyone. Not waking up because your cold and wet bed has electrocuted you is likely to be worse.
This is the main point, to me. All of the surface of the bed that is coming in contact with your body would be leaching heat rather than bouncing heat back. So, if 1/3 of your body is in contact with something that is not going to warm up, that seems like it would lead to unpleasant results.
Though if the 46 degrees is a bit of a lie, that explains it.
I believe the issue at hand is hypothermia.
Mangetout, sitchensis, and jsgoddess are right about this. Tent campers who don’t sleep on an insulating pad can get quite cold in short order, even in moderate weather, as the ground sucks the heat right out of them. Normally a mattress provides plenty of insulation in a cold room, but in this case one would be making a point of putting a heat sink into bed with them. The next step is to stuff a few blocks of ice under the covers. :rolleyes:
I could see this device being helpful in hot weather with no A/C, but I can’t see anyone wanting the bedding beneath them to ever be 46ºF.
But you wouldn’t set the bed to 46F unless the room temperature is very high. I suspect it’s safe to lie on a 46F bed if the air surrounding your body is 105F.