The Science of Baseboard Heating

In homes and commercial settings alike, heating a room is often done by way of a baseboard heater.

Baseboard heaters work by warming up the metal “fins” along the heating element. In electric baseboard heaters, this is done entirely by electricity, whereas in hydronic or hot water baseboard heaters, this is done through hot fluid moving through a pipe that runs through the center of each fin.

The thin fins allow for the best radiation of heat as air fills in the spaces between. The air heats up and continues rising past the heating element, and fresh cooler air is pulled up from below the heater. This is why it’s important to keep the space below the heater open, and clear of any debris.

The warm air continues rising and filling the upper part of a room, and the cooler air is left with nowhere to go except lower and lower to the floor, eventually ending up below the heater where it is pulled up towards the fins, heated, and moves through the room once again. This is why heaters are often located on the wall under a window, where the air is coldest and loses the most heat next to the glass.

Since baseboard covers don’t use a fan or any type of forced air movement, they are always a hot-to-the-touch solution and as such, any covers have to be as well.

Busting the Myth: Raising the Temperature Does Not Heat a Room Faster

While it may seem like a good way to speed up the process, turning your baseboard heaters to a higher temperature does not heat a room any faster. This myth only wastes energy and with that, money spent on heating you don’t need, when you don’t notice that the heater has warmed past your usual point of comfort and gotten too hot. The process happens at the same speed, regardless of what temperature you set the thermostat.

There are two different types of baseboard heaters available: electric or convection heaters and hydronic or hot water heaters. If you’re wondering if it’s safe to cover your heaters, check out our article on the safety of baseboard heaters and the advantages of installing covers.

Electric Baseboard Heaters

Electric (or convection) baseboard heaters are run entirely by electricity. While most are wired directly into a home or building’s electrical system and controlled by a central thermostat, there are more inexpensive units available that do not have to be wired and can be used by plugging into a regular electrical outlet. Both varieties are easy to install.

The perks of electric baseboard heaters are that the fins reach a higher overall temperature (approximately 180 to 200°F), thus heating a room faster than the hydronic heaters. Unfortunately, this does pose a little bit more of a risk. Electric heaters are, in general, the more inexpensive option while offering a larger range of sizes and heating capacities to best serve your needs.

Unfortunately, while electricity offers a higher temperature along the heating element, allowing them to heat a room faster, they are less energy efficient. When you turn off an electric heater, the fins cool quite quickly and only hold heat when the heater is turned on.

Hydronic (Hot Water) Baseboard Heaters

Hydronic baseboard heaters work much the same way as electric baseboard heaters, but instead of being run entirely by electricity, they operate using an internal reservoir of hot water — either connected to a central heating boiler, or heated by an internal electric heating system. This hot water (or sometimes, steam) is sent through a pipe running through a similar row of metal fins as is used in the electric heaters, but the water-heated fins do not reach the same temperature as the electric-heated fins do (approximately 130 to 140°F by the time the water reaches the heating element).

Hydronic heaters are more energy efficient, given that the water remains hot even after the heater is turned off, keeping the fins warmer for a longer period of time. This type of heater is more common for a whole-home heating system, connected to a central boiler. But sometimes, they are stand-alone heaters with the internal electric-heated reservoir.

Unfortunately, hydronic heaters are usually more expensive and offer a smaller, but adequate, range of sizes and heating capacities. These heaters can take longer to heat a room than the electric heaters, heating first the water in the system and then the fins that pass the heat to the room.

How to Tell if You Have Hydronic or Electric Baseboard Heaters

After all this, you might be sitting here asking yourself, “Do I have electric or hydronic baseboard heaters?” There’s an easy, tool-free way to check. Answer these two questions:

1) Are there easily removable end caps on the sides? Electric baseboard heaters do not have end caps that are easily removable. The entire unit is an electrical component and only the front plate comes off without tools.

2) Do you see a pipe (usually copper)?
If you remove the front panel and end caps on the sides (if you have them), and see a copper or iron pipe, you most likely have hydronic baseboard heaters.

3)Do you have a boiler?
If your heater is connected to a boiler, chances are, it’s a hot water heater.