Radiator Heaters 101: Your Guide to Old-Fashioned Heat

Radiator Heating

In the spirit of the season, over the last few weeks we have been breaking down the pros and cons of different types of heaters that you may come across. The next heater on our list is the radiator heater, an old-fashioned way to keep your family warm.

Invented in the mid-1800s, the concept of radiator heaters has a long history of keeping people warm. Over the years, this type of heater has slowly evolved into the low-maintenance, energy-efficient heaters that we know today.

While it’s definitely not the most popular type of heater nowadays, it still works great at keeping you and your family warm. Let’s take a look at how a radiator heater works, the pros and cons of owning one, and whether it’s the right fit for you.

How Radiator Heaters Work

There are two main types of radiator heaters that you should know about — Electric & Steam.

Steam Radiators

Steam radiators work by boiling water to create steam. That steam then travels up a set of pipes into the radiator, which in turn, heats up the room via radiation and convection. As the steam travels through the unit, it slowly cools down and turns into condensation. This condensation then goes through the unit, ending it’s travels back in the boiler, where it is ultimately turned back into steam.

This is the old-fashioned radiator heating method. It would be unlikely for you to find this type of system in newly built homes. However, this type of radiator heater is still in use around the world today, but it is no longer the preferred method of warming up your home.

There are a couple versions of steam radiators that you could choose from, if you’ve decided that this is your preferred heating method. These options would include:

  1. Cast-Iron free standing systems:
    The oldest version of a radiator heater, the cast-iron system is very efficient at heating up the room. However, it also takes up the most amount of room, and takes the longest to heat up. Despite these two obvious downsides, the way it’s designed allows the cast-iron system to also hold that heat for the longest period of time.
  2. Baseboard Steam Systems
    Not to be confused with your typical electric baseboard heaters, this type of steam radiator works on the same premise of steam rising and condensation falling, however, they take up very little room in your home. You can run them along the baseboards of your home in a very discreet manner.
  3. Ceramic Systems
    This is the newest version of a steam radiator. Unlike its predecessors, it’s not hot when you touch it and it’s more efficient at supplying sustainable heat. If you were going to choose a steam radiator to heat your home, this would be the one you should look for.
Honeywell Radiator Heater

Electric Radiators

This type of radiator is typically built in similar fashion as a steam radiator; however they utilize a different method of creating heat. At a radiator heater’s core is a metal reservoir filled with a special mineral oil.

This mineral oil, more aptly referred to as “thermal oil” or “heat transfer oil,” is not burned in the process of heating, so it does not need refilling or replacement. It has an uncannily high boiling point and specific heat capacity, which allows small volumes of the oil to emit remarkably high quantities of thermal energy without evaporating. Evaporation causes unsafe levels of pressure to build up in enclosed spaces, so its absence from this process makes radiator heaters much safer.

At the bottom of the heater is a heating element similar to what is found within an electric stove. It is electrically powered and is used to heat up the oil. Once the oil is heated, the warmth is convected throughout the body of the heater, warming its walls. The heat is then conducted through the metal walls and radiated into the surrounding space, filling the room with wonderfully cozy warmth.

3 Benefits of Radiator Heaters

There are many benefits to having a radiator heater. It must be noted, however, that you can also find many of these same benefits in other types of heaters.

1. Safety Considerations:

First and foremost, the main benefit is the level of safety offered to the end user. Many portable radiator heaters come equipped with a tilt sensor, which cuts the power if a radiator heater is unbalanced or knocked on its side. The heaters also retain heat well, which makes them ideal for extended use.

While it’s still not advisable to leave flammable materials draped over their surfaces to dry, they are much less of a fire hazard than other forms of heaters, such as space heaters that require more safety considerations. Lastly, they do not emit any harmful odors, gases or chemicals when used, unlike many gas heaters that require ventilation to be installed.

Please Note: Some radiators will become hot when they start to produce heat. More on that below.

2. Less Maintenance:

Radiator heaters also require much less maintenance than many of their competitors do. They do not contain any fuels that need replacing, and ventilation (or lack thereof) does not compromise warmth. Make sure you buy one that has a built-in adjustable thermostat, as this will help prevent wasted heat and lower you’re overall energy usage.

3. Reliable:

For the most part, radiator heaters are extremely reliable. If you installed a cast-iron radiator in your home today, it’s likely that it will last for years and years – and in some situations maybe even decades. This isn’t always the case, which is why you should thoroughly research every product and brand before you purchase one.

3 Downsides of Radiator Heaters

Just like everything in life, the benefits of radiator heaters also come with their own set of downsides. To some, these may not be a big deal, but they’re worth noting so that you can avoid a surprise down the road.

1. May Become Loud & Noisy

Some radiator heaters, especially steam radiators, can become noisy over the course of time. If you live in an older home with an old radiator heater in the corner, then you’ve probably heard random noises coming from your unit. These may include squeaking, banging and whistling. These unwelcome noises become very annoying for many homeowners. If you’re experiencing this, it would be wise to call a plumber to come check it out.

2. Needs Air Flow

Another downside of a radiator heater is that it must have proper air flow around the unit to effectively disperse heat around the home. Without this air flow, it’s impossible to thoroughly heat your home. Of course, different size radiators will create different amounts of heat. But, creating the heat isn’t the problem here. It’s getting that heat across the room that can be somewhat challenging. Especially if you have limited space and there’s stuff crowding around the unit. This isn’t a problem with other popular types of heaters available to you.

3. Hot to the touch

The biggest downside, in my opinion at least, is that some radiators will become very hot as it starts to produce heat. If you have something touching the unit, such as drapes or a couch, then it may get damaged or catch fire. If your children or pets touch the unit, they may get burned. While this isn’t the case with all radiator heaters, it is definitely something you should consider when researching which heater is best for you.

Tips for Utilizing Your Radiator

If you have a radiator heater mounted on an exterior wall of your home, then it’s possible that you may be losing some of the heat produced to the outside elements. This is particularly true if that exterior wall has poor insulation, has drafty windows/doors nearby or the radiator is recessed within the wall.

One trick that you can do to prevent this heat loss, is to add your own heat-resistant insulation directly behind the radiator. A sheet of foam insulation with aluminum on one side will work great at accomplishing this. You can make your own with tin foil and insulation, or buy a pre-made sheet at your local hardware store.

Simply slide this sheet of insulation between the wall and the heating unit, with the aluminum face the heater. This simple trick will help prevent the heat from slowly seeping out of your home and redirecting it back to your living area. While it may not complement the rest of your décor, this small addition will cost less than $20, but instantly start saving you money on your energy bills.

Are Radiators Better Than Other Heaters?

The answer to this all question all depends on your situation. For most people, a different type of heater would probably suit them better. This is due to the heat being able to travel further.

Radiator Heaters: Buyers Guide

As the years go by, heating methods become better because the technology inside them evolves. One hundred years ago, there was nothing better than a radiator heater. Nowadays, however, you may be better off with a different kind of heater that produces similar amount of heat and disperses it around the room more efficiently.

But, you need to take a look at your living situation. If you live in the Northeast where it snows most of the year, then a permanently installed radiator heater or wall-mounted heater may be the best fit for you. If you live in the south where it’s only cold for a few days out of the year, then you would be better off with a portable space heater that disperses the right amount of heat, but is easy to store when you don’t need it.

Is it the best heater for you?

All in all, radiator heaters are an incredibly versatile and affordable source of supplemental heat. They are reliable, durable, low-maintenance and energy-efficient. While it may not be the best, it’s still a great unit to help you follow a supplemental heating strategy.

Whether you use a radiator, wall heater or baseboard heater, having a smaller source of heat that doesn’t require you to warm up the entire home will save you money in the long run.

Just make sure that you read about the pros and cons of a radiator, as it may not be the type of heater for you.

Jeff Flowers

About Author

Jeff Flowers has been a self-described beer geek for over a decade now. When he's not chasing his daughter around, you can usually find him drinking a fresh brew and wasting too much of his time on both Google+ & Twitter.


  1. Billie says

    I have the standing radiator heaters all over my house. As you said you can put the temp for that room and not the same all over. Also the oil in them last a long time, because you can keep the heater low and at an even heat. But I have a question. When the oil leaves the heater is it safe to keep using it? Because it still heats and gives out warm air. I have about 3 in my house that has given out of oil but I still use them. So I need to know is this safe to do? Thank you.

    • Dale says

      My wife and I live in an 80 year old house with Hot water cast iron radiators, and I just learned about this method of insulating between the wall and the radiator which sounds like an easy quick fix to save some heat. My question is how do you recommend attaching barrier insulation to a plaster wall, and does the thickness of the insulation make a difference? I don’t know if I want some type of permanent adhesive stuck back there in case I choose to remove the insulation later.The radiators already have nicely designed wooden covers so I guess the insulation wont be visible. Another question is that these wooden radiator covers have screens on the front side to allow heat to flow out, but the top of the wooden covers which are a foot deep are closed and we simply use them as shelves. Should the tops of these covers be opened with screen also since my thought is that heat rises and is otherwise trapped under the cover? Thank you for your response.

  2. debbie says

    my dad is re-tired Pipefitter They have registers all over and he put down pipe’s under the floor including the basement floor you never had to go over 71 in below zero.house was alway’s warm.and are skin was never dry that is the way to go radiant heat no forced air,It caused allergies dust that can’t excape I miss it

  3. Regina Hatchet says

    My son-in-law just installed a Fireplace Insert into the actual fireplace. It has blowers on both sides, you still put firewood in it. But smaller 18″ pieces only. Question. He has not used it, just installing today. He wants to insulate the insert all around the entire outside which will never be seen, but will help keep wind from blowing down the chimney thru any cracks anywhere. What do we buy to insulate it with? A special kind? Please advise.

Leave a Reply

Your email address will not be published. Required fields are marked *