Heat in small shower/toilet room

[Art Todesco]

I have a small room with a shower stall, toilet and pedestal sink. The floor space is about 48" x 56". It is located in the corner of the house, so 2 walls are outside walls. The house is in western NC. While the room is comfortable as far as air temperature, the tile floor is cold. There is one register in the floor on one of the outside walls. The area below is garage, so it could be accessed from below by removing a piece of garage ceiling drywall and insulation. I would like to use the area below the the small bathroom as a heat plenum, hopefully warming up the floor. I know people (including me) will say, "you can't do that ....." But in my house and in many other houses in this area, they put the heat registers for the kitchen and bathrooms (not this bathroom, but the other one) in the cabinet kick plate. The duct just comes through the floor and dies there. The air just pressurizes the "kickplate" area and it eventually comes out of the register mounted up front. So if I were to wall off the area directly below the floor, insult the sides and against the garage drywall, and just like the kitchen cabinets, let the air find its way to the register. I would have to put a shut off on the duct for summer use or suffer an even colder floor in the summertime. BTW, the heat comes from a heat pump with a propane furnace for backup heat. Any comments pro or con or other ideas?

[Joe]

If you have a cold room above the garage the solution to the problem is obvious: pull down the garage ceiling drywall, pack it solid with insulation, spray foam or whatever, then see what other steps might help move warm air to the room. Remember, for warm air in you need to move cold air out.

Joe

[jamesgangnc]

Using the space between framing as hvac duct work is done sometimes. Normally it is interior wall spaces. You need to make sure the ends are sealed or add blocking yourself. I would try to put some minimal insulation on the garage ceiling side like maybe foam sheet or something.

One of the problems created by doing this is wider temp changes where the framing is located. This could result in more shrink and expanding depending on temp and humidity.

[trader4]

Here's the problems I see with this approach:

Normally there aren't heating ducts in unheated garage space, so where is the hot air coming from?

The joists have to run in the right direction

You only get one bay's worth of heating area between joists. To do the whole bathroom would require several bays.

The air has to come from and go somewhere as it flows through the bay. Where does it go?

Given the above, I would think a better solution would be electric radiant heat, which could be easily installed exactly where needed. Given it's only supplemental heat for one room, the operating cost shouldn't be very high. You;d have a control, timer, etc in the bathroom.

[hallerb]

yeah my suggested solution too, easy to install, just run when needed.

if the OP were putting in a new ceramic floor they could imbeed electric floor heat grid, but its probably not worth the effort.

or a combo fan heater for the cieling. they really warm things up:)

[HeyBub]

Throw rug.

Or slippers.

[hrhofmann]

Do you also insult your floors?

[Evan]

LOL... Just get fluffier bathroom area rugs...

~~ Evan

[hrhofmann]

The op referred to "insult" ing the sides of the space, he meant "insulat"ing the sides. Since we are former co-workers from many years ago, the OP knew I was trying to be humerous. I'll try to do better next time.

[Peter]

You are considering a very complicated solution when there is a much simpler one. You say that the room temperature is comfortable; your only complaint is that the tile floor is cold. Get a mildew resistant area rug and if necessary, cut away the part of the rug that otherwise would cover the floor register. Problem solved.

[bud--]

I agree that using the hot air system is not likely practical, and that electric might be the best fix (other than a rug). I think there are electric panels that mount to the bottom of a subfloor to heat the floor. Like trader suggested this probably has to be installed in multiple joist spaces.

Maybe a plug-in (GFCIed) electric heater blowing across the floor when (before) you use the bathroom?

If you walk on the floor with bare feet the floor has to be warmer than the walls or air because you get real good heat transfer.

[hallerb]

years ago I was single and lived alone, would leave furnace set at 50 most days.

but i could come home shower and still leave furnace set at 50.

come home leave house cold, turn on shower, close door warm up bathroom, then shower, nice warm and comfy.

cost? just some extra hot water... which also adds huidity to home.

i would turn heat up at night to 62 since i spent so little time here....

later i got a electric blanket and often let home cold at night

[Art Todesco]

Huh, huh, I don't understand, spell check didn't catch anything?? But it did catch humerous! I'm insulated that you would publicly be humorous at my expense. :)

BTW, to not make this a private communication between 2 people, I do like the idea of putting "warming panels" under the subfloor, as someone suggested. I did a little investigation but will have to do more. But, if I do that, I still have to take down the garage ceiling and insulation. I also still have to spend $$$ on electricity to warm the thing. That's why I originally like the idea of a warm plenum under the floor. The rug is looking better and better!