Why Isn’t My In-floor Heater Working?

My in-floor heater is not working!

Walking on a cold floor with bare feet should be banned as a cruel and unusual punishment by the Geneva Conventions. Fortunately, fixing a broken in-floor heater is possible.

As always, let’s back up a bit for a little background information. When it comes to in-floor heaters, you have a choice: hot water or electrical. Hot water in-floor heater use pipes located just under the subfloor. If they’re not installed already, it’s a pretty big job to add them.

On the other hand, you could lay electrical systems right on the flooring and cover the heating cables with your flooring. Of course, electrical in-floor heating systems are not perfect, either. Here are four issues that might come up:

1. It doesn’t produce enough heat or takes too long to heat up.

If this problem isn’t caused by the thermostat (more on that later), it’s probably the insulation’s fault. Your electrical system is a radiant system system, so the heat just spreads out from the cables. That means you need insulation to redirect the heat, so it warms your floor and not just the space below. Make sure the insulation you buy is compatible with your flooring.

2. The heating system trips the circuit breaker.

If this happens, your breaker is probably either too small or it’s the wrong type. Always check the circuit breaker type and rating you need for your electric in-floor heating system.

If the breaker is the right size, then the heat system’s wiring might be damaged. That’s not very likely, but it’s not impossible. To be 100% sure your wiring is in good shape, do resistance testing on the heating cable as you install it. You’ll find instructions on how to do that in your manual.

3. The system isn’t working after you installed the flooring.

It’s pretty easy to damage in-floor heating cables. If you drop something on it or accidentally cut it, it’s not going to work. Measure resistance with an Ohm-meter or a multi-meter at every stage of the installation (especially when you get the product and after the flooring installation). If they are damaged, it’s a lot easier to handle them early on in the process. Keep checking every step of the way!

4. Utility bill is too high.

A 10 square foot electric radiant heating mat uses only 120W of energy – about the same as a 100W light bulb. That means keeping your floor warm and cozy (and avoiding the wrath of the Geneva Conventions) would cost under a dollar a day.

However, you will reduce that cost significantly if you use a programmable thermostat. A programmable thermostat can save you up to 70%, because it will let you only heat your floor when you want it heated (and not all day, every day).

Okay, now you know a little about your electric in-floor heating system. What do you do when it’s not working?

Chances are you have a lousy wall thermostat. (told you I’d tell you “more on that later”).

The wall thermostat is like a traffic cop. It controls the line voltage to the heating cables. To make sure it’s working:

  • Use a non-contact voltage tester to make sure there is voltage.
  • If there isn’t voltage, check the circuit breaker or fuse at the service panel. Reset the breaker or
  • replace the fuse and check for power again.
  • If you have power at the thermostat, check for voltage at the splice box.
  • If you don’t have power at the splice box, you have a bad thermostat.

Guess what? Fixing this problem is easy. If it’s not working, you just need to replace your thermostat. To do that:

  • Turn off the circuit breaker.
  • Take the cover off the thermostat.
  • Loosen the terminal screws and disconnect the wires.
  • Remove the old thermostat and bring it with you to the store to get the right replacement.
  • After buying the new thermostat, reverse the steps above.

If the problem wasn’t the thermostat, chances are you have a defective heating cable or mat. The defective cable or mat (or part of it) needs to be replaced.

Replacing all or part of a defective cable is a pretty big job – and not the kind you’ll want to do yourself. Instead, you should hire a good, reliable technician like the pros at Early Bird. Next time you have trouble with your in-floor heater, give us a call. If you’re thinking “No, no, no, I can do that by myself…” you’re going to need more instructions than you’re getting from this blog.

Good luck!