How to calculate Wats per sq.meter by dT

[zilvis79]

Example : heated floor surface area 100 sq.meters.lets say room height 3m, so 300 cubic meters volume of air in the room, RH=50%, florr surface temperature is 30c, desired romm temp 22c, dt=8.

Question : how to calculate energy radiated by Wats per sq.m (W/m2)

[frank]

You are missing a vital part of the equation - TIME

Over time, the input temperature of 30C will bring the room up to 22C over TIME, providing that the heat input is greater than the heat loss.

Watts (J/S) is a measure of heat /time

[DTLarca]

For underfloor heating the floors should not exceed 29°C but for bathrooms which are typically 33°C.

For floors the surface film heat transfer coefficient is limited to approximately 10-11W/m²K so for your 8K TD the maximum heat transfer would be 8K x 11W/m²K = 88W/m²

But you ask how much would be radiated? I'm not sure how to divide Q into radiant and convective components? I don't know the proportions - I don't think it matters, does it?