4382 ft^3 room, heat from -20 to 70

[jdbrandt]

What is the required kW to heat a room measuring
10' x 19'4" x 22'8", in a climate that gets as low
as -20 deg. F (30 year low), to maintain internal
temperature at 70 deg. F.

Walls are insulated at R6.
Ceiling is insulated at R19.
Floor is poured concrete.


Chromolox 'quick table' indicates about 11 kW.

Electrical here, not too used to these type calcs.

 

[ChasBean1]

Jbrandt, based on your data I would use:

Q = U•A•dT

U = 1/R (units of BTU/Hr•ft2•°F)

Total wall area = 840 ft2 of R6
Total ceiling area = 438 ft2 of R19

Total KW is 3.69 (walls) + .61 (ceiling) = 4.3 KW

This is very basic based on R values given. Neglected are infiltration losses, solar gains, floor losses, internal gains, and air boundary layers.