Does anybody else have the experience that even when the room temperature is the same, you still feel colder when it's frost outside?
Physically, I mean. Very odd, I think.
I think I got it!
TCGirl found this...
"Believe it or not, your body and all other objects are always giving off or absorbing heat by radiation. Heat transfer by radiation goes from a hotter object to a cooler object - like from the sun to earth, or from hot coals to you, or from your body to the cold walls of a lonely castle on a dark and stormy night."
Doesn't quite explain it, but I realized: the thermometers, unlike a body, are probably only reading the air temperature.
The other source of heat which we normally don't think about is radiation heat. From the walls! In warm weather, it's considerable, in frost it goes away, and this might well make it a lot harder to keep a good body temperature.
Which says to me that a building in a cold climate really should be very well insulated all around, otherwise you might never be really comfortable. I don't think higher air temperature is a good substitution for all that radiation, it warms the body in a very different way. (Not sure how, yet.)
One trick I use is to have a fan circulating the air, just to make sure that the heat is distributed evenly. Sometimes, that can make a difference, because without that, the heat may be going up the walls toward the ceiling without warming central parts of the rooms. Seems to work for me.
There is a scale called the Bedford Comfort index which takes account of air temperature, humidity, radiant temperature of surrounding etc to come up with an index. I was able to demonstrate to a class of students that their subjective estimate of comfort within a classroom matched pretty well with values using this scale from appropriate measurements.
Well, there you are then, thank you. Interesting.