Edwin Pawlowski wrote:

"Furry" wrote in message

... It takes at least an hour, sometimes 2, for the basement to
warm up enough that the thermostat stops calling for heat. 1200 sq ft
is a lot of concrete to heat up but isn't that a long time?

.... 1200 ft^2 of 4" concrete is 400 ft^3 with about 25x400 = 10K Btu/F of
capacitance, or more, if there's no insulation beneath. You might warm it
from 50 to 70 F in 2 hours with a 10K(70-50)/2h = 100K Btu/h boiler.

One of the drawback to radiant heat is the slow response. However, that is
not necessarily a cost factor.

It is, if there's an unoccupied setback, compared to a heating system with
no time lag, because the heated space needs to be warmer for some time
before the setback, and it stays warmer after the setback, so it loses
more heat to the outdoors.

If the heater is firing for 2 hours at 30,000 Btu, it is using the same
amount of fuel as a burner firing at 150,000 Btu for half that time.

No. The former uses 60K Btu. The latter uses 75K Btu.

Nick