I think the air is almost transparent to infrared.
The underfloor heating uses a low temperature; the floor is ~24 C. There is little air movement because there is a very small temp gradient. With a radiator or a stove, its temperature is much higher, prob > 60 C. So you will have a column of hot air that rises to the top of the room and stays there. And at the floor level it is much colder.
Comments
I think the air is almost transparent to infrared.
The underfloor heating uses a low temperature; the floor is ~24 C. There is little air movement because there is a very small temp gradient. With a radiator or a stove, its temperature is much higher, prob > 60 C. So you will have a column of hot air that rises to the top of the room and stays there. And at the floor level it is much colder.