How to install an Electric baseboard heater

If you’ve read this article on forced air vs baseboard heating, you’ll notice that baseboard heaters are more cost-effective and efficient for heating areas that are under-served by your main heating system. More importantly, they’re relatively easier to install as they eliminate the need for ductwork in the new space. This makes them ideal for various spaces like basement workshops, sun rooms, and garages. Also, they work well as a supplemental heat source, which makes them a perfect option for living spaces that don’t get enough heat from your HVAC system. 

Most homeowners do baseboard heater installation within a couple of hours as it’s a relatively simple task. However, this can be quite challenging for beginners as it may involve the installation of at least one completely new dedicated circuit. Using a dedicated circuit for the electric baseboard heater prevents the circuit from tripping and overloading. 

Don’t let all that stuff bother you though! In this article, I’ll show you everything you need to know on how to install an electric baseboard heater. 

• Choose the right electric baseboard heater size

The first thing you need to do before you install an electric baseboard heater is to look for the best baseboard heater that meets your heating needs. Luckily, baseboard heaters are available in several sizes. 

There are various ways to determine the right baseboard heater size for your home. In most cases, the heating capacity or rating of these units is measured by wattage. A common rule of thumb is that 10 watts of heat provide adequate warmth to cover a floor space of 1 sq. ft. However, this may vary depending on other factors like ceiling height, the number of windows, wall insulation, etc. 

Secondly, you can determine the right baseboard heater size depending on its length. Most units come in standard lengths ranging from 24” to 96”. Generally, a 240V 24” baseboard heater has a rating of 350W (ideal for a small bathroom), while a 96” heater has a rating of 2000 – 2500W (suitable for a 200 – 250 sq ft room). Alternatively, you can combine 2 or more baseboard heaters that combine to produce sufficient heat to meet your heating needs. 

Although the heating capacity of baseboard heaters is usually measured in watts, the actual output is measured in British Thermal Units (BTU). This rating can be quite useful when comparing the heat capacity of electric baseboard heaters to hydronic/ water-based units.

In addition to determining the right heater size, it’s worth noting that electric baseboard heaters come in two styles; 120V and 240V. Most professionals prefer the 240V circuits as they provide more wattage capacity than 120V circuits. This makes it easy to add more baseboard heaters to the circuit without overloading it. 

In terms of heating capacity, 240V units generate about 250W of heat per linear foot. For instance, if your room needs about 3000W of total heating, you’ll need a total of 12 ft of 240V baseboard heaters. 

• Choose the best thermostat for an electric baseboard heater 

Some baseboard heaters come with an inbuilt thermostat, so they don’t need a wall thermostat. Such models are recommended for providing supplemental heat in small spaces or a room that only needs to be heated occasionally. However, if your preferred heater doesn’t have an inbuilt thermostat, you have to mount a separate thermostat in the wall to control the heater.  

Most low-voltage thermostats that are commonly used for forced-air furnaces are not compatible with electric baseboard heaters. Instead. Electric baseboard heaters work with line-voltage thermostats. This simply means that they carry the full amperage and voltage load running from the circuit to the heater. Unlike low-voltage thermostats, these temperature-controlling devices don’t have transformers to step down the voltage & amperage load. 

That aside, line voltage thermostats are available in 2 basic styles; double-pole (4-wire) and single-pole (2-wire). Professionals prefer 4-wire thermostats as they control both sets of hot wires in the circuit. Best of all, this design is generally safer as it reduces the risk of shock if the thermostat needs to be serviced. 

• Determine the location of the baseboard heater and thermostat 

After calculating the right baseboard heater size and choosing the best thermostat for your heater, the next step is to determine the ideal location for both devices within the room. Electric baseboard heaters are usually installed beneath the windows. This allows them to exploit the natural air currents moving into the room to distribute heat uniformly throughout the room. However, the heater should not be obstructed by furniture or other items for efficient operation. Other standard practices to follow when choosing the best location for your electric baseboard heater include; 

• Don’t install the heater below the wall outlets since power cords hanging down over the units can cause a fire hazard. 
• Leave a space of at least 1” between the heater and the floor to allow for convective airflow. However, you can mount the baseboard heater directly on the floor depending on the model. 

As for thermostat placement, thermostats for electric baseboard heaters provide the most accurate temperature reading when mounted on an interior wall and away from any heat source. Note, there are some places you need to avoid when mounting a wall thermostat. 

• Plan Routes for Electrical Cables 

The last step before the baseboard heater installation process starts is to carefully plan the routes for your electrical cables. These cables usually run from the main circuit panel to the thermostat and from the thermostats to your electric baseboard heater. Make sure you give careful thought to the electrical cable route as this is one of the most difficult parts of the installation process. 

What you will Need 

• Stud finder 
• Wire strippers 
• Cable fish tape
• Screwdriver 
• Drywall saw 
• Drill & bits 
• Level 
• Volt Meter 
• NM electrical cable 
• 240V circuit breaker 
• Electrical wall box 
• Wire connectors 
• 1.5” drywall screws 
• Double-pole line voltage baseboard heater thermostat 
• 240V Electric baseboard heater 
• Black electrical tape 
• ½” cable clamp 

Step-by-step guide on how to install an electric baseboard heater 

1. Turn off the power 

Turn off the power for the room you are installing the baseboard heater in at the main circuit panel. Use a voltmeter to test the supply wires to ensure that they don’t have any current running through them. 

2. Install the wall box for the thermostat

Use the drywall saw to cut holes in the drywall where the electrical cables for the thermostat and baseboard heater will emerge. Install an approved wall box where you plan to mount your thermostat. A wall box is not needed for the baseboard heater since it has an inbuilt connection box. 

3. Run cables from the circuit panel 

Run 2 lengths of NM cable from the main circuit panel to the baseboard heater thermostat location, and from the thermostat to the location of the baseboard heater. If you’re planning to install multiple baseboard heating units, run the cable from the thermostat to the link. Use fish tapes, drills, and saws to run cables through finished walls to make your job easier. 

4. Breaker & Circuit wiring 

A 240V electric baseboard heater requires a dedicated 20A or 30A 240V electrical circuit. A 30A circuit can safely provide 3800W of power, while a 20A circuit can produce up to 5700W. In addition, a 30A circuit requires a 10-gauge cable, while a 20A circuit cable requires a standard 12-gauge cable. 

It’s also worth mentioning that a circuit cable is usually a grounded 2-wire cable, where both white and black wires are hot wires. If you’re only using the white wire as a hot wire, put a black/ red table on it to show that it’s hot. 

In this case, circuit wiring simply involves installing a 20A circuit to wire the electric baseboard heater. To accomplish that, use a 12-2 non-metallic encased cable to connect your main electricity supply panel to the heater. Interestingly, you don’t have to install a fuse box since baseboard heaters have one built-in. However, you should install a breaker to make final connections at the main switchboard. 

In addition, connect both white and black electrical cables of the 240V electric baseboard heater to the double 20A breakers. And wrap a piece of black or red tape around the white cable near the breaker to show that it’s hot instead of ‘neutral’. Lastly, connect the bare-copper ground cable to the bottom bus of the circuit board. 

If you’re planning to install a 120V baseboard heater, connect the black hot wire to a single-pole 20A breaker. And connect the white wire to the neutral bus and the ground wire to the ground bus. 

5. Install the thermostat 

If you’re installing an electric baseboard heater with a separate thermostat, you have to run a circuit cable from the heater to the thermostat wall box. Strip the circuit wires and use wire connectors to connect them to the wire leads on your thermostat. Mark the white wire with black tape to serve as a hot wire for 240V applications. 

In some 4-wire thermostats, the wire leads have labels to show whether they should be connected to the wires running to the heater (load wires) or to the wires coming from the circuit panel (line wires). For instance, the heater cables are usually labeled ‘T’, while the line wires are coded ‘L’. However, the coding tends to vary from one manufacturer to another. 

Strip about ¾” of insulation for each conducting wire and connect the 2 hot wires from the breaker to the 2 wires on the ‘line’ side of your thermostat. Connect the bare ground wires together to the ground wire/ screw on the thermostat using a pigtail wire.

For 120V applications, the black hot wire from the circuit breaker is connected to the thermostat’s ‘line’ wire. While the black hot wire heading to the baseboard heater connects to the ‘Load’ wire on your thermostat. Moreover, join the white ‘neutral’ wires in the wall box. And connect the bare ground wires to the ground wire/ screw on the thermostat. 

 Once the thermostat wiring is complete, tuck the wires into the wall.  Secure the thermostat to the wall box with mounting screws and install the cover plate. 

6. install the electric baseboard heater 

Remove the knockout on the back of the connector box of the heater and install a ½” clamp to the box. Run the circuit cable through the cable clamp into the heater’s connection panel, leaving 6-8” of extra wire extending beyond the clamp. Remove the cable sheathing inside the connection panel. Then strip ½” of insulation from the end of each conducting cable and tighten the cable clamp. 

Next, locate the wall studs behind the baseboard heater using a stud finder. Use 1 ⅝” drywall screws to fasten the heater to at least 2 wall studs. Remember to use a level to keep the unit level if it’s not placed directly on the floor. 

7. Baseboard heater wiring 

Look for the factory wiring connection on the heating element in the baseboard heater’s connection box. Follow the manufacturer’s instructions to disconnect the wire connector holding the connection together. 

Connect one factory wire to the hot wire from the 240V circuit cable, and connect the 2nd factory wire to the other hot wire from the circuit cable. As mentioned earlier, both black & white wires act as hot wires in a standard 240V circuit since there is no neutral wire. For that, it’s good to mark the white wire with a piece of black tape to show that it’s a hot wire. 

Lastly, connect the bare ground wire to the green ground screw in the baseboard heater connection box and re-install the connection panel cover. 

8. Install & Connect the circuit breaker 

Shut off the main breaker, open the panel and install a 240V 20A double-pole circuit breaker in the main electrical service panel. Next, connect the black & white hot wires to the screw terminal connections on the breaker and connect the new ground wires to the grounding bar of the service panel. Snap the breaker into an empty slot in the main service panel, close it up and power the main breaker back on. Make sure you make the panel index to show the baseboard heater breaker. Similarly, make the white and black wires with black or red tape to show that they are hot wires. 

Note: Installing a circuit breaker is a potentially dangerous task. So, if you’re not familiar with the parts of a service panel, hire a professional electrician to install and connect it for you to avoid the risk of electrical shock. 

9. Test the baseboard heater 

Turn on the baseboard heater circuit breaker and wait for about 5 minutes to ensure that the device isn’t working when it’s in the ‘Off’ position. If the unit is heating, check the wiring as it could be done incorrectly or the heater could be defective. But if it’s not heating, turn on your thermostat at the highest temperature setting to test if it’s producing enough heat and responding accurately to your thermostat settings. Next, turn off the thermostat to determine if the heater shuts off. 

What if my new baseboard heater smells like burning? 

Electric baseboard heaters are usually shipped with a protective coating on their metal fins. As a result, they may produce an odd smell or emit a small amount of smoke when you first operate them. However, the protective coating tends to dissipate after a few uses. Alternatively, run your baseboard heater for 30 minutes after ensuring it’s working properly. 30 minutes of heating give it adequate time to get rid of the oil residue that it might come with from the manufacturer. 

How much does it cost to install an electric baseboard heater? 

The average cost of buying a 120V electric baseboard heater ranges from $50 – $120, depending on the wattage. On the other hand, a 240V baseboard heater costs about $100 – $300, depending on heat capacity and other factors. In addition, installing a 240V baseboard heater might require an experienced electrician.

 Typically, the cost of installing a baseboard heater ranges from $379 to $1,200, depending on the specifics of your project. Also, the labor will be influenced by other factors like the type & model of the baseboard heater, the number of heaters being installed, etc. More notably, the national average labor to install an electric baseboard heater is between $75 and $250 per hour. However, you may either pay lower or higher depending on various factors.