How to Calculate the Minimum Size of an Electrical Baseboard Heater

Sizing Up Electric Baseboard Heaters

As a guideline, baseboard heaters use around 400 to 2,000 watts of power. Higher wattage means more power to create heat: a 1,500-watt heater can heat a 150-square-foot room (10 by 15 feet with an 8-foot ceiling). You can use smaller baseboard heaters to add warmth in rooms heated by central furnaces. Although you can use a 1,500-watt baseboard heater as a sole source for heat, it is a lot more costly than running central heating systems.

The writers at Stelpro share a simple equation that can be used as an electric baseboard heat calculator to see how much wattage you need in a room. The equation is room area x 10 = wattage. If you have a room that is 10 by 10 feet, for example, its area equals 100 square feet. Multiply 100 by 10 to get 1,000. This formula to determine baseboard heater requirements works for average rooms that have 8-foot ceilings.


Cost to install baseboard heating system by type

A baseboard heating system costs $200 to $1,300 per unit with installation. Heaters are placed along the baseboards, walls, and under-cabinet toe spaces to release ground-level heat, which rises to warm a space. Heat is produced by a direct electrical connection or hydronic, fluid-based system.

Baseboard heating installation cost by type
Type Average cost to install (per unit)
Electric baseboard heater $200 – $1,100
Hydronic baseboard heater (water or oil) $430 – $1,200
Wall heater $370 – $1,200
Toe kick $420 – $1,300

Electric baseboard heater installation cost

An electric baseboard heater costs $200 to $1,100 with installation or $50 to $130 for the unit alone. Electric heaters require no ductwork or plumbing, so installation is cheaper and easier than other heating systems. Electric units draw in cool air and heat it with electric coils.

Long electric baseboard heater installed in living
Long electric baseboard heater installed in living room

Hydronic baseboard heater cost

A hydronic baseboard heater costs $430 to $1,200 with installation or $180 to $320 for the unit alone. Hydronic models circulate hot liquid from an internal reservoir or the home’s boiler to provide radiant heat. Hydronic units heat slowly but stay warm long after the running cycle for more efficient heating.

Baseboard vs. wall heater costs

An electric wall heater costs $370 to $1,200 per unit with installation, depending on if the unit is surface-mounted or recessed in an interior wall. A wall heater provides fast, even heat by using a fan to circulate air. Wall heaters are ideal for bathrooms, workshops, and other small spaces.

Baseboard vs. wall heater costs
Factors Electric baseboard heater Electric wall heater
Unit cost $50 – $130 $100 – $500
Installed cost (per unit) $200 – $1,100 $370 – $1,200
Time to heat 30 – 60 minutes to heat a room Less than 10 minutes to heat a room
Lifespan 20 years or more 8 to 12 years
Temperatures Operates at lower temperatures and is cooler to the touch than a wall heater Operates at higher temperatures than baseboard a heater
Space required 6 – 8 feet of length and less than 12 inches in height 12 –16 inches length and height
Noise Nearly silent; a good choice for bedrooms Audible fan noise, but less than a standard home refrigerator

Toe kick heater installation cost

A toe kick heater costs $420 to $1,300 with installation or $175 to $430 for the unit alone. Toe kick heaters are space-saving and typically located under cabinets, vanities, and stairways to provide supplemental floor-level heat when needed. Electric and hydronic toe kick heaters are available.

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Baseboard Heater Costs and Installation

Electric baseboard heaters cost between $25 and $250. Convection baseboard heaters are on the lower end of that range, often under $60, and hydronic baseboard heaters are on the higher end, usually between $200 and $250. The cost of installation depends on whether you need a professional electrician to connect a hardline heater to your home’s electrical wiring. A plug-in, of course, doesn’t need a professional install.

Hardwiring a baseboard heater into your home’s electrical system may require running new wires through the wall, running existing wiring to the heater’s intended location, and installing a new circuit on your electrical panel. While it’s possible for a highly capable homeowner or DIYer to perform these tasks, it’s usually best to hire a pro.

An electrician’s labor cost can be between $75 and $250 an hour, and the total cost to purchase and professionally install a baseboard heater is usually between $400 and $1,200. Whether you call a pro or DIY, you may also need to remove a portion of the existing baseboard trim.

How To Choose a Hydronic Baseboard Heater

Finding the best hydronic baseboard heater for your home will largely depend on the size of the space you want to heat. This can be determined by the heater’s power rating.

The output rating for electric hydronic baseboard heaters is based on watts (a measurement of electrical power consumption to be converted to heat energy), while the rating for hydronic baseboard heaters is in British Thermal Units or BTUs (a standard measurement of heat energy).

Generally, an electric heater should have 10 watts of power for every square foot of living space, and a radiator should put out 20 BTUs per square foot. For example, a 100 square foot room would require at least a 1,000 watt (100 x 10) electric hydronic baseboard heater, or a 2,000 BTU baseboard radiator. It’s important to ensure your boiler has a large enough BTU output capacity to accommodate the rating of the baseboard radiator before it’s installed.

Baseboard heat cost per month to run

Baseboard heat costs $480 to $900 per month to run for 10 hours per day, depending on the home size. In larger homes, regions with high utility costs, or colder climates where heaters run more often, baseboard heating costs $1,500+ per month.

Baseboard heaters energy usage

A well-insulated room requires 10 watts per square foot of space, while a poorly-insulated older home needs up to 15 watts per square foot.

Baseboard heaters energy usage
Room Area Watts required Daily energy use*
100 sq. ft. 1,000 10 kWh
150 sq. ft. 1,500 15 kWh
300 sq. ft. 3,000 30 kWh
400 sq. ft. 4,000 40 kWh
500 sq. ft. 5,000 50 kWh

*Based on 10 hours per day of use.

Use the following formula to calculate the cost per month to run baseboard heaters:

Power (Watts) x Price Of Electricity ($ per kWh) ÷ 1,000 = Heating costs per hour

Is baseboard heating expensive?

An electric baseboard heater is one of the most expensive ways to warm a home, according to the U.S. Department of Energy. Electric baseboard heating costs more than other fuel sources, including propane, oil, or natural gas. However, baseboard heaters are cost-effective for secondary zoned heating.

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Calculating Heater Wattage: A Quick and Easy Method

A very simple method to determine how much electric baseboard heating wattage you need can be found by calculating the square footage of the room, then multiplying it by 10 watts to produce a baseline wattage requirement. 

For example, if you are heating a 12-foot x 12-foot bedroom, the space includes 144 square feet. Multiplying this by 10 watts shows that the necessary heater wattage for the room is 1440.

This base wattage calculation method presumes that the room uses modern construction methods with typical wall, ceiling, and floor insulation and that it has 8-foot ceilings. If the room differs from these specifications, it's recommended that you make the following adjustments: 

  • Add 25 percent more wattage if the ceilings are 10 feet high rather than 8 feet. 
  • Add 50 percent more wattage if the ceilings are 12 feet high rather than 8 feet.
  • In an older home, multiply the square footage by 12.5 watts, not 10.
  • In an ultra-insulated home, multiply the square footage of the room by 7.5 watts, not 10.

For the sake of our example, let's assume that the room has normal specifications. With 144 square feet, the required wattage is 1440 watts, which means you could heat the room with a single 1500-watt baseboard heater or two 750-watt heaters.

Formula 4


Q = the required heat output of the baseboard at design conditions (Btu/hour) from Step 6.

q = the heat output of one foot of baseboard (Btu/hour/ feet) from Step 7.

Round off L to the next higher whole foot length, referred to as “Lrounded.”

Step 9: Calculate the outlet temperature of the baseboard using:

The Drip Cap

  • Sizing your heaters properly helps to ensure your home maintains a comfortable temperature regardless of fluctuations in weather.
  • Calculate the square footage of the space you want to heat with baseboard heaters.
  • Assuming you have a 10-by-10 room with average insulation, you would need 1,000 watts of baseboard heat if the room has an average ceiling height.