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Heat the bathroom

As you can see in the pic, due to the toilet and sink vanity, the area of floor available for heat mat is about 25 s.f.


  • Gene DavisGene Davis Member Posts: 71

    A guy I know doesn't believe bathrooms need heat by any other means than what you get from one of the electric resistance products you put under the tile floor, aided by a heat lamp in the ceiling.

    This, for a locale with over 8000 heating degree days and a design temp of -30F.

    The house is to be heated with a small mod con doing RFH in the slab in the walkout basement, with panel rads on the small main floor. The bathroom shown in the pic, with an 8'-8" w x 8' h outside wall and two windows, will require 1075 heat input to offset the loss at design temp. A small panel rad was specified, but the builder wants to do the infloor and heat lamp, dispensing with the rad.

    Electricity is expensive here.

    Whaddya think? Will an electric heat mat (Sun Touch, Nu Heat, Warm Tile, etc.) plus heat lamp, suffice?
  • jpjp Member Posts: 1,935
    Electricity is expensive here.

    i think you have answered your own question here?

    is that a shower in that nook? great place for heated tile walls.
  • ALHALH Member Posts: 1,790

    Better do some radiant walls or ceiling, a supplemental radiator, or a towel warmer. To heat that room to a comfortable temperature, the floor surface temperature would be pushing the limits.

  • With what looks like about 45 sq.ft. of heatable floor area requiring an output of 24 btu/sq/ft and 85F floor temp @ design conditions (assuming 70F room air), it [seems] you're in the "perfect" range for a floor that will be nicely warm.

    I would NOT however consider the "heat lamp" as contributing to the heat load! If it's what I'm thinking--an infrared bulb in a recessed fixture in the ceiling--such REALLY SHOULD be installed with a timer switch. I use such in nearly all of my bath designs, but only for radiant heat when you're drying off. Such bulbs will cause severe "sunburn" in a surprisingly short period of time.

    As long as the electric floor warming system chosen is sufficient for design output (DON'T OVERSIZE!) and the homeowner understands that on a cost-per-btu basis that it will be relatively expensive to heat, I have to say "go for it" as the comfort factor is likely to be nearly perfect.

    If budget allows however, I would suggest that a panel radiator with TRV be included and you certainly have a suitable wall for mounting. The TRV will prevent the panel from providing heat when the electric floor is sufficient, yet provide "backup" should it fail, prove insufficient or undesired.
  • Jim PompettiJim Pompetti Member Posts: 549

    When it comes to a bath room on an outside wall I would rather have heat and not need it , then need it and not have it
  • hot rodhot rod Member Posts: 7,011
    350 watts (1190 btu/hr.) worth of electric

    mat under the tile would be my choice. Keeping in mind that load is only at design days. Nice to be able to warm the bathroom without firing a boiler for that micro load.

    I suspect with the bathroom door open it will recieve some heat from the rest of the home?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • hot rodhot rod Member Posts: 7,011
    throw in an electric towel rad

    if the floor area can't make the load. Runtal has a nice selection with intergral thermostats.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • jpjp Member Posts: 1,935
    I agree hot rod

    but what about a 10 gallon ele hot water heater for heating the bathroom in the off season, boiler during heating season?
This discussion has been closed.


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