I have electric ceiling heat. How can I tell whether my thermostats are low voltage (24 volt) or line voltage (120 or 240 volt)?

What size are the wires connected to the thermostat, 12, 14 gauge (regular house wiring) or 20 gauge (small wire like your door bell)? Do you have a multi-meter?

Find and read the manufacturer's label on the thermostat.

There the voltage rating will be listed.

Most electric heat stats are line voltage. There are a few systems that use low voltage stats, which control a relay or contactor that does the actual line voltage switching.

Thanks to hkstroud and tkrussell.

Both answers were very helpful.

Hutch153