Radiant Heat In Ceiling Wiring

mtplus

For a remodel, I have to take down a wall, which involves moving 2 room thermostats that are connected to ceiling radiant heat panels. In order to move them, I need a longer run of wire. The ceilings are plastered. Does anyone know of a way for me to extend the wire to the thermostat withoout taking down the ceiling? (code prohibits burying junction boxes inside of walls).

Sparky Joe

Do you have attic space above? Are the wires 120V or low voltage?

mdshunk

You can extend the cold lead of the heat cable if you want. Just make sure that you're not inadvertantly connecting to the hot lead at some point beyond the cold/hot junction. An accessible attic space above is my first thought too. Worst case, you'll just need a blanked wall box.

mtplus

Radiant Heat is 240.

No Attic space.

Thanks for replies.

Sparky Joe

I've never seen any of this, how do they run that in the ceiling? Or what precautions do they take to make it safe?

K2

In the late 70's they would sent the radiant heat out in a piece of drywall with 2 wires hanging out and marks where not to nail. It was scarey and I think short lived.

CE1

Think of it as MI cable, only in sheetrock. I have only seen two installations of this stuff. The first one was a fire and the stuff fell out of the ceiling. The second was when the HO cut a hole in the ceiling for a paddle fan and cut the heat cable wires in the sheetrock and come winter wondered why the heat didn't work.

K2

In the early 80's I saw some that was foil and plastic that would sit in the ceiling joist space above, supposedly radiating to the living space below using a regular drywall ceiling. I still know of a fourplex with this type of heat. The downstairs people have an electric bill 4x what the upstairs people pay in the winter.

Sparky Joe

From the past 2 responses, you may want to just abandon the stuff. Fire in your house while you're asleep, I'll pass on that.

It'd make better sense to have the heat trace in floor wouldn't it? Or is it the dense sheetrock that helps it radiate?

CE1

Like I said before think of it as MI cable. Having the heat source in the ceiling like this is not very efficient because heat rises and the room would be colder closer to the floor that you get. The heat would tend to go up and away from the room you want to heat which equates to wasted energy. Heated floors are definitely better than heated ceilings which are why you do not see this type of system anymore.

K2

The theory and the way they sold these ceiling radiant systems was that the panels radiated energy and the energy was converted to heat when it reached an object like a chair or the floor. So theoretically you were not pushing heat from the ceiling to the floor and the heat was originating low and rising.... I didn't buy it back then either.

blackrd

Some of the radiant ceilings were constructed by fastening to a blueboard type material, and then buried under a couple coats of plaster. This was one of the earlier methods, around late 50's to maybe late 60's. Personally I wouldnt touch this system without waivers from the homeowner or GC. Most painters I know have never seen radiant ceiling heat.

Sparky Joe

With the heated floors I've seen they have to use a thin concrete(gypcrete) on the floors, so you don't get hot and cold spots. That's why I suspected they were installing them on ceilings.

mdshunk

I'm a little surprised to learn that some of you consider this an "old fashioned" system. I still put it in from time to time. Chromalox is the brand I use. It is cable, that comes on a roll. You specify the number of square feet you're heating, and that dictates how big of a roll of cable you get. It staples on top of 3/8" sheetrock with a power crown stapeler. Then, it gets veneer plastered over by the rocker. Same idea as the "Easy Heat" under floor cable heating system that is getting popular in bathrooms, only upside down. Ceiling heat is a decent alternative for electric heating where you don't have a good place to mount a baseboard heater.

katttfishh

I did a few of these in the 70s. They were ordered to exact lengths for each room and came with warnings not to cut or lengthen the wire. Each room had its own thermostat and the wires were stapled to 3/8 rock at exact 3" centers then we covered it with another 3/8 sheet. It was considered to be the cheapest way to heat at that time or at least thats the way they were marketed. Only heat the rooms needed not the whole house. A fireplace was a neccessity cause it could take a few hours to get a room warm.