Programmable Thermostat for Radiant Floor Heating System
LESLIE: Reggie in Montana listens to The Money Pit on KGEZ. And Reggie, what’s your question? How can we help?
REGGIE: How best to manage in-floor heating. My mother-in-law moved into a new condo, recently, and she’s of the old school where when you go to bed at night you turn down your heat, turn it back up in the morning or (inaudible) …
LESLIE: Well, you should be, too, to save some energy dollars.
REGGIE: Well, yes, but what we’ve noticed is that it seems like when she turns the heat back up again in the morning …
REGGIE: That it takes a long time for the room temperature to come up and by the time it gets up to where it’s triggering the thermostat, that giant concrete rock that is her floor is now giving off too much heat for too long and it overheats the room and such. And so we were trying to decide is it better off to manage it by just maintaining a constant temperature all the time? Or, if you do make adjustments, just make it in one or two degrees until you’re comfortable?
TOM: Well, I think that’s a great question. And you do point out one of the downsides of radiant heat; and there are not very many. But one of the downsides is the radiator itself is essentially the entire floor of your house. And so, unlike say, a cast iron radiator or a sheet metal radiator – either of which will heat up the house very, very quickly – the radiant floor does take a little bit of time.
Leslie, I agree that he should continue to use a clock setback thermostat but, perhaps, the dropping of the temperature might not be as much as you would normally do with, say, a cast iron system; perhaps only 10 degrees or so.
LESLIE: Well, what kind of setback do you recommend? Like during the day, we’ll operate our house on 71 and 72 and at night we’ll drop it to like 68. I mean we’re not dropping it to 60.
TOM: Yeah, what are you dropping it to?
REGGIE: Oh, she would be … she would be dropping her temperature down to like 60 degrees at night and then turning it back up to 71 or 72 in the morning. And it takes a long time to get that rock warmed up.
LESLIE: Well, especially with the concrete flooring.
TOM: You know what you might want to do? It takes a long time for the slab to cool off, too. So let’s say if she goes to bed at ten o’clock, I would set the thermostat to go down at 9:00; see, because you still have some heat left in the slab, right? And then, if she’s going to wake up at 6:00 in the morning, I’d bring that thermostat up at 5:00 to give it an hour to bring up. So, whereas if it was not a radiant slab, you might be using shorter periods of time to go it off and on – because it is a radiant slab and it holds heat longer but, conversely, takes longer to heat up – I would just adjust the times accordingly.
LESLIE: Right. So instead of having your mom operate the thermostat, replace that thermostat with one where you can put a timer control to bring the temperature up and down so she won’t even have to worry about it.
TOM: Oh, yeah, you definitely don’t want to have her do this manually. You definitely want to do it with a clock thermostat and take that decision away from her. It’s really not necessary for us to do … for her to do that. Because, then, she will overheat the house. She’ll just crank it up until she’s comfortable and then it’ll be too hot. And like you say, you’ll drop it down. But the idea of saving energy is really moot at that point.
REGGIE: Okay. Thanks a bunch.
TOM: You’re welcome. Thanks so much for calling us at 1-888-MONEY-PIT begin_of_the_skype_highlighting 1-888-MONEY-PIT end_of_the_skype_highlighting.