Baseboard Radiators: What You Need To Know

The pros, cons and talking points of this popular heating system.

Have you noticed that everything seems to go through cycles? Be it home decor, fashion or home appliances, it's obvious that we're in the midst of a "retro" trend, how else could you explain the sudden resurgence of cast iron baseboard heaters as a go-to selection for new home, office and apartment construction these days?

It's easy: They actually work.

Yes, retro is cool; but these radiator heaters wouldn't be creeping back into new construction throughout the world if they couldn't get the job done. Function trumps form at the end of the day, and these babies can deliver day in and day out.

Radiated heat is much more efficient that forced air heat (such as furnaces), for reasons I'll go into later in this article. And the fact that they've got a great "vibe" doesn't hurt, either - so long as you're into that sort of thing.

How Does A Cast Iron Baseboard Radiator Work?

It's a very simple process, actually. Water or steam flows into the radiator via a supply line, and in turn the radiator dissapates the heat throughout the room. It does this through the series of distinctive fins that give it it's classic "look." But keep in mind that in some designes the fins are actually hidden from view behind a metal casing; so keep that in mind if you're looking to buy a cast iron baseboard heater online sight unseen.

The term "radiator" simply means "heat exchanger," and typically is reserved for any type of heat exchanging system by which fluid flows into it. The heat is exchanged ("radiated") from the fluid inside to the space outside through convection. It's the same exact physics principle that car manufacturers use to keep engines cool, the difference here is that the heat isn't "waste" as it is in the automotive industry, instead it's the actual desired effect.

Why Cast Iron?

Because it has excellent heat exchange properties (don't worry, I won't use too much physics in this article). Simply put, cast iron heats up fast and disapates heat very efficiently. Have you noticed that the old wood burning cook stoves are always made of cast iron? This is why. Other materials would not be nearly as efffective at keeping rooms warm.

Where does the steam or hot water supply come from?

Typically it comes from a central boiler or water heater located in a mechanical room (or HVAC room), but there are always exceptions. Some manufacturers have even been contemplating a new design that includes a built-in heater within the baseboard radiator itself, so all you'd need to do is pipe in a water supply line and you'd be set. But so far they haven't measured up to specs, and will likely stay in the development/testing phase for quite some time.

If your home, office or apartment was initially designed for radiator heat, it's probably already got an elaborate network of supply pipes (either water or steam) winding throughout the building, tied to a central boiler or water heater system. Installing this network is intensive and expensive, so a cast iron baseboard radiator probably isn't a smart choice as an "add on." If you're currently building right now, it's best to plumb in your entire supply network while you're still in the early construction phase, because this is where it's cheapest. Even if you choose not to run cast iron baseboard radiators, you'll have the infrastructure in place should you chose to add them later on. Just ask your contractor to cap off the pipes.

How Do You Control The Temperature?

That depends on your system. If you have a residential baseboard radiator system, you can often control the boiler the same way you would with a gas or electric furnace. You'd wire it up to a thermostat and program it to turn on and off at specific temperatures.

If you're in a bigger building, such as an office comples or apartment, you probably don't have that option. This is why cast iron baseboard radiators are typically built below windows. You can crack your window to allow some of the heat to escape if it's getting too warm.

I mentioned there were two types of baseboard radiators, steam and water, let's take a look at the advantages and disadvantages of each.

Hot Water Baseboard Radiators

Hot water is piped into the cast iron baseboard radiator through a pipe, and as it travels through the radiator it dissapates its heat into the heater's fins, and thus into the room. Hot water systems can come pressurized or unpressurized. Pressurized radiators are force fed hot water through a pump system (such as a hot water heater), so the water coming through is always hot. Unpressurized, or "gravity feed" radiators" don't use presurized water, but instead are plumbed into a central boiler that's built below floor level. As the water is heated, it naturally rises to the radiators, where the heat is transfered into the room. As the water loses heat, it sinks back down to the heating system.

Steam Baseboard Radiators

Steam was used as a heating medium long before hot water, which makes it both retro cool and also clunky and tempermental. Instead of water, steam is sent through pressurized pipes and into your cast iron baseboard radiators, where it is transfered to the living spaces. Steam has a couple of big advantages, namely it's much easier to distribute than hot water, especially in larger buildings such as skyscrapers and large apartment complexes.

The downside is that they are inherently less efficient than their hot water radiator cousins, because the higher temperature of the steam leads to increased heat loss along the way.

Another downside: Pipe hammering. This is a lound banging sound created by the pressurized steam picking up liquid condensation inside the pipes (it's called a "slug" if you want to get technical) and then slamming it into the pipe wall at super high speeds. Not only is this very annoying, it's actually bad for the pipes themselves. Hammering pipes is often minimized by a well designed system, but it's almost impossible to completely get rid of it. That's why those old buildings with cast iron baseboard radiators make so much darned racket.

Are Baseboard Radiators Efficient?

You bet! More so than standard furnaces even! That's because the heating elements are are located withing the living space itself, not burried in an HVAC system and seperated by endless ductwork. All of that stuff actually results in heat loss along the way.

Think about it this way: Can you imagine if the heating element within your furnace was actually sitting in your living room? It'd be pretty darned warm in there, right? Well that's basically what cast iron baseboard radiators are, a heating element that's in the exact spot where you want the heat. Obviously for safety purposes your baseboard radiator wouldn't be nearly as hot as your furnace heating elements and exchanger, but you get the idea.

Long story short, regardless of if you're wanting them for aesthic design purposes or for their heating effieciency, cast iron baseboard radiators deserve your consideration.