Radiant Heatloss

Brad White

J-P has a good reason, losses from a higher delta-T between the floor and a cold underside.

The "box in space" still has the same requisite areas, u-factors and delta-T's inside to outside. No changes there but perhaps for the floor and edge losses if improperly or inadequately insulated.

The principal efficiencies with radiant are the lower water temperatures you can use (promoting use of more efficient boilers) and the physiological perception of occupants feeling warmer (bathed in radiant flux) while the air temperature may in fact be cooler than a conventional thermostat would maintain.

adambuild

!

As we don't do any radiant, I have a question. Is the heatloss for a radiant floor home different than the heatloss for a home heated with baseboard or cast iron rads? For example, two identical homes, one heated with radiant floors, one with c/i rads. Would the heat loads be the same? If not, why?

Thanks in advance, Adam

jp_2

same

heat load will be the same.

how the heat is generated and how it is applied is the big difference. a big heated floor improperly insulated will loose more of the generated heat, suggesting that the heat load is different.

Ron Gillen

Delta T

No difference in calculating heat loss but in practice there may be some difference in ceiling losses due to stratification. With forced air and more so with vaulted ceilings the air temperature at the ceiling can be considerably higher than with radiant. Higher delta = more efficient heat transfer to the outdoors.