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 the Size

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

Keep in mind how old your windows are and how much heat they may lose. Consider 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 one for colder days, as opposed to having the minimum number, 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 It


You may want to install one 1500 watt unit or two  1500 watts units, depending on how much warmth you desire. Either way they are usually placed below windows, where most of the heat loss occurs.

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

You'll also need to determine a location for the thermostat if one is not built into your unit already. 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 heating units, 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 them to each other, creating what's called 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 heating unit, 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 area. Also get rid of any old paneling pieces around the wall cutout.

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

Have the Right Wires

A baseboard heating unit 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 is 12-gauge, which can handle up to 16 amps, or up to 16 ft. 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 circuit of cable between the electrical panel and thermostat location. It may take a long time to snake the cable between the points.

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 heater's 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's ground screw.

Run Electrical Cable to the Heater Location(s)

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

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

Install the Heating System


Set it in place. Read the manufacturer's instruction carefully. Remove the front covers from both ends of the heating unit. Create a small hole in the wall for the cable.

Remove one of the round knockouts 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 unit.

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 it to the wall, adjusting to make sure the unit is level. Secure the wiring compartment covers. Do this for each unit you may have.

Test It Out

After you finish wiring all the heaters, turn the circuit breaker back on. Check to make sure it is working properly. Be aware that the first time you start it, 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.


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 unit

6. Mount the heating system

7. Run cable to the next unit and repeat steps 5 & 6 for each additional option

8. Turn the circuit breaker on and test the unit to make sure it's working properly.

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