The plots below show the temperatures for a cathedral ceiling room.
The peak is 16 ft high.
The temperature sensors are at 2 ft, 6 ft, 10 ft, and 14 ft above the floor.
The difference in temperature from the 2 ft level to the 14 ft level is about 3F. From 6 ft up to 14 ft its only about 1F.
Does it seem like the furnace is cycling more than it should?
16 ft tall cathedral ceiling -- the post with the blue tape has the data logger temperature sensors mounted at 2, 6, 10, and 14 ft off the floor.
Plot of temperatures from about 1pm to about 10 am the next morning.
Closeup of 8 pm to midnight. The 10 minute up and downs are the furnace going off and on -- stops when the night setback at 10:30 is reached.
Here are some more results on stratification sent in by Chris:
Radiant Floor Temperature Profile
Here are some test results on floor to ceiling temperature stratification for a radiant floor heated living room with 9 foot ceilings -- posted on the Taunton Forum:
I don't have a data logger, so I used a paper and pencil.
Outside temp today,16*F
Took readings at 1', 5', and 8' from the floor in a space with 9'ceilings.
The first column held steady all day long, didn't move over .2 degrees. The next 5 columns were after I lit a fire in the fireplace. The last column was when DW started cooking supper. The readings were taken in a room that is 24' across from windows to fireplace. the readings are from the center, 12' to both fireplace and windows. Fireplace is sealed combustion, no draft in room from fireplace.
All Day Fire Supper
8' 71.2* 74.3* 74.6* 75.6* 76.2* 78.4*
5' 71.2* 73.4* 73.7* 74.2* 74.2* 75.2*
1' 70.1* 72.2* 72.2* 71.9* 70.8* 71.2*
Looks to me like the fireplace started a convection current from the fireplace across the ceiling, down across the windows, and back across the floor, just like a fintube radiator. I did see a 1* spread before the fireplace during the day. Odd thing is that the floors are the heat emitters, it was cooler there. I just got the data so I'm not sure what that means that the floor was cooler and it's the heat source.