Here’s a birdseye view of a 45 sf bath with one exterior wall. Two windows, one 2×2 near the toilet, and one in the 3×4 standup tiled shower is a 24×32 glassblock deal.
Heating degree days over 8500, design temp is -30F, central heat is done with mod con boiler running max 155F water in panel rads.
Heat loss analysis shows this room at needing 1075 Btu/h at design temp. One small panel rad was specified.
The panel rad was scrapped in favor of electric under-tile heat cable in the 25 sf of floor available for it, basically the 3′ wide run from the door to the outside wall. A heat lamp in the ceiling will supplement.
The floor mat stuff is capable of delivering about 12 watts / s.f., which I compute runs to less than 90 Btu/h. I don’t know about the heat lamp.
Electric carries a relatively high cost, at about 17.5 cents.
I think the room is underheated, and that the decision to scrap the rad and do the cable was a bad one.
What do you think? Will the room be chilly when the temps go south of zero?
