Christmas Electric Company — Radiant Ceiling Heat Specialists.



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What is electric radiant heat?

Electric radiant ceiling heat is a very small, continuous, length of heat wire that is run back and forth on the first layer of the ceiling. It is attached to the ceiling with staples, and then a skim coat of 1/8″ to 1/4″and/or a second layer of dywall can be installed. The ceiling cable terminates at the wall mounted thermostat where it is fed with 110, 208, 220 volts.

How does it work?

The radiant heat cable must be in tight contact with the ceiling material so that it can radiate its heat to first overcome the cold ceiling material. The ceiling must get to a temperature above that of the ambient room temperature before it will radiate any temperature that you can feel it is because of this that we suggest that the room thermostat not be turned off at night, instead just set the thermostat back about ten degrees before going to bed. In the morning adjust the thermostat back up to the (normal) setting. If the thermostat is turned all the way down at night then in the morning it will take too long for it to return to the normal temperature.

What often happens is that the thermostat is turned off or way down at night then in the morning it gets turned all the way up in the hope that it will warm the room faster. Before the room gets warm enough the person will leave for work, leaving the thermostat turned up to its highest setting, making the room unbearable hot all day. If this scenario is repeated often enough you will end up with a very large electric utility bill.

All electric heat is costly to use but it is clean, comfortable, and easy to use. Try to heat only those rooms that are in normal use. Bedrooms can be set to a lower temperature, than say, the living room or den.

What not to do!

Do not make any holes in the ceiling because very likely you will hit one of these wires, damaging or breaking it. Do not set the thermostat above the normal comfortable setting.

What to do if the heat does not work.

First check the circuit breaker to see if one has tripped or been turned off for the summer season. Next check the thermostat to see if it has been turned high enough so that the heat would come on. After doing both of these procedures wait for about an hour to see if the room gets warm, if not, then it’s time to call us:



We at CHRISTMAS ELECTRIC, since the 1940s have tried many ways to to find and repair electric radiant heat without doing a lot of damage to our customers ceilings. We have now been repairing this kind of heat for the past 42+ years, with a 98 percent success rate.


1. Check breaker box for any breaker that may have been turned off for the summer season.

2. Check thermostat for correct voltage and operation. Most common test is flashing line conductor to the load conductor of the thermostat, if we get a spark, it’s checked out ok, but if we don’t we receive a spark, then we have a break in the ceiling heat cable.

3. We then remove the thermostat and cap off the line conductors.

4. Then we introduce high voltage from a transformer to the ceiling heat (cold lead) cables. This will find an arc across the break in the ceiling heat cable, creating a hot spot in the ceiling, where we must then fine the Hot Spot with an infrared heat gun. Once we have narrowed it down to the break area, we then open a small area in the ceiling to expose the heating cable, usually the hole is no wider than ¾» and no longer than 6″-8″.

5. Once the wires are exposed, we strip back 1″ of the wires insulation and clean the bare conductor with a knife blade preparing it for soldering.

6. We then slide a piece of Heat Shrink over the insulation of the heating cable.

7. Now, we are ready to couple the wires together with a special (splice) over our heating conductor and crimp it into place. Now, we solder the splice and let it cool before sliding our heat shrink over our splice, apply heat to heat shrink.

8. Now, we can staple our heating cable back to the drywall using round 9/16″ staples.

9. Test your splice by the flashing test at the thermostat; if you have a spark, you are now ready to repair your hole.

10. Repair hole by filling it with joint compound or plaster patch, depending on your ceiling. You must wait 24 hours after patching, before normal use can take place.

Preparing Ceiling For Ceiling Heat Cable Replacements

The power must be turned off for that Ceil Heat System and the thermostat must be removed and the flex from the thermostat box to the ceiling must be found. (This ensures safety for the next steps.)

If your ceilings have an acoustical treatment (popcorn texture), it must be scraped off so we have somewhat smooth ceiling to install your new Ceil Heat Cable to. If there are any cracks or holes, they must be filled; this cable is very dependent on being encapsulated in drywall mud. The smallest amount of air around this cable will burn a hole in the cable, resulting in heat failure. If you want to install Recessed Lighting or a Ceiling Heat Fan, now’s the time to do so.

After the new cable has been installed, a skim coat of drywall mud must be applied over the cable; no less than ⅛» and no less than ¼» of mud must be applied and allowed to cure. You can either have a smooth ceiling or have it re-textured. (Your choice).

After the ceiling has had time to cure, you’re now ready to prime and paint your ceiling. After the paint has had time to cure, we’ll come back in and test the system to install your new thermostat. You’re now ready to use your Ceiling Heat as you need to.

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