A space heated this way puts you in direct contact with the heat source. Homeowners feel comfortable because the entire floor surface is acting as a radiator. Consider this: With a forced air system, the difference between the temperature at the floor and at the ceiling can be as much as 15 degrees. With a radiant system, the difference in temperature can be as little as two degrees.
The science behind radiant
Radiant heating systems warm people and objects rather than just the air. ASHRAE studied the thermal environment around the human body and developed something referred to as the Ideal Heat Curve. The Ideal heat Curve is best described by using these images.
Ideal Heat Curve
Here, the Ideal Heat Curve shows that for maximum comfort, the warmest temperatures should be at floor level. Cooler temperatures are best kept at head and ceiling levels. The Ideal Heat Curve also allows comparison of the efficiency and comfort levels of radiant floor vs. traditional forced air heating systems.
By comparing radiant floor and forced air heating systems one can easily see that in forced air, heat becomes trapped at the ceiling causing an inversion of the Ideal Heating Curve.
You can’t fool science. A space heated by radiant heat follows the Ideal Heat Curve.