Over time, the resistive elements in your electric baseboard heater may fail. By testing the resistance of the heater, you can determine whether you need to replace the unit.
Step 1 - Turn Off the Power
You want to be sure that, in addition to the thermostat, the breaker to the heater is turned off.
Step 2 - Calculate the Resistance
Resistance is measured in ohms. In order to find the resistance you will be testing, divide the heater’s wattage by its voltage to find the amperage; then divide the voltage by the amperage to find the ohms.
Step 3 - Connect and Test
Using a screwdriver, remove the cover from the heater to expose the wiring. Connect the red and black leads of your ohmmeter to the two wires going to the heater (red in “ohms,” black in “com”). The resistance reading should be very close to your earlier calculation. If the reading measures zero, or is very high, there is most likely some sort of short in the heating element. In this case, you need to replace it.