How To Install Your Baseboard Heater

Many owners of older homes that lack central heating choose to install baseboard heaters, which are permanent fixtures but require less extensive ductwork than other systems.

It's possible to install a baseboard heater by yourself, especially if you have some experience working with electricity. Follow our handy guide to have your home heated in no time!

***Note: Always check local building codes before starting the installation. Be sure to follow the manufacturer's instructions, and use proper care and follow safety rules.

Calculate Your Baseboard Heater Size

The first step is to figure out how many watts of electric heat are required to heat the space. Most spaces require 10 watts per square foot of space for homes built since the 1970's.

Keep in mind how old your windows are and how much heat they may lose, and how well insulated the room is. If your home has little or no insulation, you can generally multiply its square footage by 12.5 to figure out how many watts you should look for. Remember, adding additional units won't increase the cost of operation, so installing an extra baseboard heater for colder days, as opposed to having the minimum number of baseboard heaters, may be a good idea.

Supplies You May Need

• Measuring tape
• Baseboard heater
• Electric tester
• Pry bar
• Wire cutter/stripper
• Wire nuts
• Screw driver

Decide Where to Put Your Baseboard Heater

You may want to install one 1500 watt baseboard heater or install 2 heaters totaling 1500 watts, but either way electric baseboard heaters are usually placed below windows, where most of the heat loss occurs.

A 240 volt heater uses the smallest wire size and the least number of circuits. Make sure you have access to the electrical voltage you will need for your baseboard heater.

You'll also need to determine a location for the thermostat if one is not built into your baseboard heater. The thermostat should be located on an interior wall in dead air space (such as behind a door), and NOT above a heat source.

If you have multiple heaters, you can install a separate thermostat for each, since that will allow you to turn on only as many heaters as you need. Otherwise you will connect heaters to each other, creating a chain.

Remove the Old Baseboard Heater

Turn off the power at the circuit breaker box. Use a tester to make sure the power is off.

On the old baseboard heater, remove the retaining screws and remove the heater from the wall. Clip the ends off the wires and place wire nuts on the ends for added safety. Carefully remove the trim and baseboard from the wall heater area. Also get rid of any old paneling pieces around the wall heater cutout.

If there is no old baseboard heater to remove, remove the baseboard with a pry bar if necessary, so your new heater will sit flush against the wall.

Have the Right Wires

A baseboard heater needs its own circuit so don't try wiring one to a circuit with other appliances as that could overload the circuit. The typical wire you will need for a baseboard heater is 12-gauge, which can handle up to 16 amps, or up to 16 ft. of baseboard. 10-gauge wires are much more expensive, and 14-guauge wires are too thin.

Install the Thermostat

Trace a switch box on the wall at 60" up from the floor. Cut the wall open for the thermostat. Provide a 2 wire

Most thermostats have three wires: a black one where the electricity flows through, a white neutral wire, and a bare/green grounding wire.

The black wire attaches to the side of the baseboard heater thermostat. The white wire should be connected to the load neutral wire, and the bare or green wire is connected to the load ground wire. You'll also need to attach the pigtail to the heater ground screw.

Run Electrical Cable to Baseboard Heater Location(s)

For in-heater thermostats, run the main feeder cable to the first heater. For a wall-thermostat system, run a cable from the thermostat location on the wall to the baseboard heater, and run a main feeder cable to the thermostat location.

To daisy chain multiple heaters, run one cable from the circuit breaker or wall-mounted thermostat to the first heater, then a second jumper cable (with the same gauge) from the first heater to the second. You can add another jumper from the second to a third heater, and so on, if you wish.

Install the Baseboard Heater

Set your electric baseboard heater in place. Read the manufacturer's instruction carefully. Remove the front covers

Remove one of the round knockouts of the baseboard heater with a screwdriver and pliers. If the wire will enter the baseboard from the floor, remove the knockout on the bottom of the electrical connection box. If the wire enters from the wall, remove the knockout in the back of the unit.

Install a wire clamp in the hole you just made. Feed the wires through the heater clamp, connecting the ground wire to the appropriate terminal on the heater. 

Make sure you strip enough of the jacket/insulation from the end of the house wiring and the heater's wiring to connect the wires. Push the heater's wires into the house wires until a 1/2" of the jacket is inside the wiring compartment. Secure them with wire nuts. Also make sure that the ground wire is secure.

For all wire connections, twist the wires together and cover the wires with a connector.

Push the heater tight to the wall. Screw the electric baseboard heater to the wall, adjusting to make sure the unit is level. Secure the wiring compartment covers. Do this for each baseboard heater you may have.

Test It Out

After you finish wiring all the electric baseboard heaters, turn the circuit breaker back on. Check to make sure the heater is working properly. Be aware that the first time you start up the baseboard heater, you may see smoke. This is due to the coating burning off, and the smoke should clear after about 5 minutes. Make sure you have proper ventilation for the smoke.

Summary

1. Turn off electricity

2. Prepare the cable wires

3. Install the wall-mounted thermostat

4. Run the electrical cable from the wall-mounted thermostat location to the heater

5. Complete wiring for the heater

6. Mount heater

7. Run cable to next heater and repeat steps 5 & 6 for each additional heater

8. Turn the circuit breaker on and test the baseboard heater.