Radiant floor heating questions

beenthere

You can run hpex at 180°F also. Its not the tubing that is the problem.

Its the quick temp swing that you can get from the floor using high water temps.

The heat has to transfer from the pex to the joist, to the floor. So the joist become a lot warmer/hotter then they need to by the time the floor gets warm/hot enough. The stat stops calling for heat. But the joist are still putting more heat in the floor. So the room ends up over heating.

warmsmeallup

Sorry I haven't answered your questions. I've been working.

The only low voltage system you can use to heat both the floor and shower is Heatizon Systems' Floorizwarm Tuff Cable. The kits come with the cable, clips, digital programmable thermostat with in-floor sensor and the transformer. You will also need to buy (1) cold lead splice kit to be able to cut the element and 'jumper' it through the curb into and then back out of the shower.

As for the size, I need you to clarify if the dimensions you've given (5' x 6') are the total bathroom or the actual open floor dims? Also, the 3 x 3 shower is the total shower, right? You need to deduct the (approx) 1sf for the drain area.

As for primary heating, whether you use electric or hydronics, if you are planning on making the radiant heat your only source for heat, you should do a heat loss calculation. Once you have the load numbers, you design the system to generate enough btu's (or watts) to much more than replace what you are loosing. Most important thing to keep in mind when accomplishing a HLC; garbage in, garbage out!

You asked how hot the element gets. The element doesn't get hot and then wait for the floor to catch up. Since the element is embedded in the mortar, the mortar (or SLC/Thinset, etc) will heatsink the heat off the cable and make it all heat up evenly. The standard set back is about 7 -10 degrees. The tstat regulates the floor temp.

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secutanudu

Great info, thanks. I should have been more accurate with my numbers. Here's a to-scale picture of what my bathroom will look like (1"=1'). I just talked to the guy at the pluming supply shop...my house has mostly radiators, some baseboards, all on the same zone. He said this is not ideal, since the radiators eat up a lot of hot water.

He told me for my bathroom (40 sq feet)...NORMALLY I'd need a 3-foot baseboard, but I'd need to oversize it since my zone also includes radiators. My current thinking is doing a 4-5 foot radiator for general room heat and line-voltage electric for everywhere but the shower. If the 4-5 foot radiator doesn't cut it, I can easily supplement it with the floor heat.

Ideally I'd like the floor heat in the shower too....so I need to look into pricing it out, but that's my thought for now.

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warmsmeallup

I can't print that to any kind of scale. You'll need to measure the exact open square footage you wish to cover. Give the room and shower separately. I can then advise you what you'll need (low and line voltage) but you'll have to shop for it elsewhere. This forum is for informational use only.

Measure it so that you cover 3" - 6" into the toilet. I wouldn't want your toes to be cold!

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ink

I was told that if you wanted a warm floor for a warm floor, electric is probably better. If you want a floor as a heat source, then hydronic is the way to go.

secutanudu

I have decided to go with electric floor heating. I was thinking of using SunTouch shower-approved elements. They come in both mat form and loose wire that you stick to the floor with double-sided tape. Are these products good?

Here is my bathroom. I plan to heat both the orange shaded floor and the blue shaded shower.

Any recommendations?

Thanks.

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