I believe back in the '70's in Tidewater, VA, we used 10 watts per square foot. Looking at the calculator Bob posted, it says we were low.
And looking at that same calculator it appears that 2 watts per cubic foot would be closer.1 watt per cubic foot is a good place to start, but many factors to consider.
Your example is quite impressive.Baseboard 240Vac heaters consume approximately 250w per lineal ft. The State Climate Zone rating for the location of your project is the first qualifying data required for local energy code baseline using resistant heating. For a quick answer using a prescriptive method, the following example will give an idea...
Climate Zone 1 (sea level) WA State......By Design= 8 BTU/sf....By Prescript=20 BTU/sf
Climate Zone 2 (High Elevation) 500'+.....By Design=12 BTU/sf....Prescription= 25 BTU/sf
Example 18' x 10' Room= 180 sf..........(1 w= 3.412 BTU)
Location at Climate Zone 1 by Prescription= 20 BTU x 180 sf / 3.412 = 1055w (4' heater)
A basic design would be to install a 20% higher output heater with wall thermostat. The larger heater warms the room quicker to the stat setting shutoff level. For a more energy saving choice, IR radiant heater would heat quicker and save up to 15% energy. rbj
Hi Hardworking,Your example is quite impressive.
180 square foot room gets a 1,000-watt heater? Seems small, even if you add 20%.
180 x 10 (watts per square foot) = 1,800-watt heater, we would have installed an 8-foot heater (2K-watt).
That's the method I've used in the past.Have any of you done a heat loss calc. on a building, then sized the baseboard from that?
Yes....on a room by room basis stat zone controlled. It is very difficult to determine heat loading by single volume extrapolation in residential design unless the structure was one room with same ceiling height without windows.Have any of you done a heat loss calc. on a building, then sized the baseboard from that?