How to Retrofit Radiant Heat Under a Tile Floor
LESLIE: Alright, now we’re going to talk to Dan in Virginia who’s looking to heat his tootsies in the bathroom.
What’s going on?
DAN: I was just driving home and I’m in the midst of redoing my bathroom. And my wife took up all the carpet in the house, so now we’ve got beautiful hardwood floors. But when she takes a shower, she always yells and complains that her feet are cold. (Tom chuckles)
LESLIE: Hey, our feet are cold. They really are cold.
TOM: Cold tootsies.
DAN: (chuckles) So what I want to do is redo the bathroom floor by putting – and putting a heater to heat up the tile in the bathroom floor.
TOM: Ooh, you can do that.
LESLIE: Like a radiant heat.
DAN: Well, I’ve seen them at Home Depot and Lowe’s but I’m really not sure of which one to get and what’s the best one. Is it 110 or is it 24 volts? Is it thermostat-controlled or what?
LESLIE: Well, that’s a lot of questions. There are a lot of good options out there. There’s – I’ve seen the ones that roll out like sheeting and have the electric filament in that.
But Tom, do you recommend the one that’s like forced through water? How do you do it?
TOM: Well, in this case of a retrofit like this, you’re probably going to want to use a radiant system that’s designed to go under tile. And they’re electric and the material is designed so that you can place tile and mud right on top of it. And the way they work is usually off of a thermostat or off of a timer or off of both. There are different wiring options. But basically, what you do is you set it to warm the floor until it comes up, in that particular room, up to the temperature that you want.
Now mind you, Dan, getting your wife those toasty-warm feet is going to cost you some because it’s not terribly expensive to put in but it is expensive to run. And what I would recommend is you use it only when you need it. So for example, in the morning you can throw it on or set it on a clock thermostat so it comes on half-hour before she’s going to get in there and then goes off. Because if you leave that thing on all day long, it’s not going to add a whole lot of heat to the rest of the house but it is going to add a whole lot of cost to your energy bill.
LESLIE: Yeah, but it’ll save him all that pain when she puts those freezing-cold feet on him in the bed. (Dan laughs) That’s our personal form of torture.
TOM: Only a woman would describe cold feet as painful. (Dan laughs)
LESLIE: They hurt.
TOM: You know, guys, we just like, “Yeah, it’s cold. Alright. Put a towel down.” (chuckles)
LESLIE: Yeah. Well, when I put them on your back next time I come visit your house, you’ll be sad. (Tom and Dan laugh)
DAN: I also have another little scenario, too. I do have baseboard heat around the house.
TOM: Right. You have baseboard hot water heat?
TOM: Well, another thing that you could do, if you have hydronic heat, is you can use a hydronic system. So there are systems that fit under tile that are water-based as well; the same way that they’re electrically-based. And that, in fact, would be a lot less expensive. And since you have the hot water access, that would probably be the least expensive way to do it. And if you did a hydronic heating system and then you had 1/2-inch to 3/4-inch of mud, that would be a really warm, toasty surface that won’t cost you a whole bunch of money to maintain.
DAN: OK. And I can also put that on a timer or heater stat with electric motor.
TOM: No, you couldn’t because that’s the difference. See, that would be part of the whole zone that’s covering that part of your house.
TOM: So it will on all the time but it wouldn’t be so bad. Because you remember, the rest of the house is going to be run off the thermostat. Now, you know, if the thermostat happens to be in a room that’s pretty far away from the bathroom and that room happens to be warmer than what the bathroom is – like say the thermostat’s toward the south side of the house and the bathroom you’re concerned about is on the north side of the house – then what you might find happens is that the boiler never kicks on and warms that floor when she wants it to do.
DAN: Right, so half the house will be cold and half the house will be warm.
TOM: Well, not half and half but it just – you know, you’re basically taking your commands – your boiler’s taking the commands from wherever the thermostat is.
DAN: Right, right.
LESLIE: Like we had – at our vacation home, we have like a wood-burning stove and, unfortunately, it’s placed right near the thermostat. So when you go in during the winter months, the house is freezing. So you want it to heat up, so you light a fire but then the thermostat will never kick on to warm the rest of the house. So it’s – you’re stuck a little bit.
TOM: Yeah, fireplaces that in any way face thermostats are a bad thing because the radiant heat affects the thermostat and the heating system will never kick on.
DAN: OK, great. Well, you gave me some options to think about. Thank you all very much and I enjoy the show.
TOM: You’re very welcome, Dan. Thanks so much for checking in from Virginia and calling us at 1-888-MONEY-PIT.