Radiant Floor Heat Output
How much heat a radiant floor puts out per square foot, and whether the surface stays comfortable.
Example
You enter
- Solve for surface_to_q
- Floor mean surface temperature (°F) 85
- Room air temperature (°F) 70
You get
- Heat output 39.3 Btu/hr-ft^2
Details, formula, and sources
q = 2 x (T_surface - T_room)^1.1 Btu/hr-ft^2, with the ~85 F surface comfort cap (~39 Btu/hr-ft^2 in a 70 F room). An 85 F floor over a 70 F room gives 39.3; solving inverse, a 30 Btu/hr-ft^2 load needs an 81.7 F surface. Solves either direction. The panel manufacturer's ratings and the loop layout govern.
q = 2 x (T_surface - T_room)^1.1 Btu/hr-ft^2; inverse T_surface = T_room + (q/2)^(1/1.1); comfort cap ~85 F surface.
The radiant-floor heat-output relation q = 2 (Tsurface - Troom)^1.1 with the ~85 F surface comfort limit, from ASHRAE / radiant-panel practice, by name.
The floor heat-output correlation and the ~85 F comfort limit are standard published radiant-heating results.
Estimate. AHJ and licensed professional govern.
Field names used by the API: mode, t_surface_f, t_room_f, q_btuh_ft2
- Output q = 2 x (T_surface - T_room)^1.1 Btu/hr-ft^2radiant-panel practice
- Comfort cap mean surface temperature limited to ~85 F (~39 Btu/hr-ft^2 in a 70 F room)ASHRAE comfort
- Tubing separate the surface temperature follows from water temp, spacing, and coveringscope of this tile