Radiant space heaters are confusing in their own right. We’ve already talked about oil-filled portable heaters that look a lot like the “radiators” you might find in an apartment. These are not those. The premise behind radiant heaters is entirely different. The oil-filled heaters discussed in our previous post are passive in that they do not rely on a fan to move heated air through a room. Radiant heaters can make the same claim of passivity (though there are fan-forced models) but, unlike those oil-filled heaters, radiant space heaters aren’t meant to heat the air at all! Not directly, at least.

Confused? Don’t worry, we’ll get to the bottom of it. When an oil-filled heater (or a heater with coils over which a fan blows) is doing its job, air is heated and circulated through a room. Heaters without fans rely on convection, the flow of air created when warm air rises and cool air sinks, to generate air flow and circulate the air they warm. It’s a slow process but works fine. A heater with a fan may function to warm a room more quickly because it is moving that warm air around the room more quickly (and more loudly). Radiant heaters don’t care about air at all. Like the sun, radiant heaters warm people and objects, not the air. Those objects, in turn, may release heat into their environment which, in turn, warms the air around the objects over time.

If you’ve ever stood in your mechanic’s garage on a cold day, you may have encountered a radiant heater. They are also often found just above the entrance to stores, providing a welcome dose of warmth to those entering and exiting the store or waiting outside for a pickup. Many warehouses use them as well. Radiant heaters are often found in outdoor or semi-outdoor areas where the lack of an enclosed, insulated environment means that conventional heating options are simply a waste of money (all the warm air simply blows or rises away). Since radiant heaters don’t bother to heat the air, just the objects in their path, that problem is largely negated. There is still inefficiency here in that the objects they heat such as concrete floors are still releasing that heat to the air where it’s carried away as waste. But the people standing in the path of heat from the radiant heater and from the heated objects releasing heat are still comparatively warm.

Frankly, radiant space heaters are a miracle of modern technology and I’m a big fan. The emergence of portable radiant heaters on the market means the rest of us can benefit from this type of heating without having to hard mount an industrial radiant heater in our house. Used properly, these types of heaters can serve as a smart alternative to other options. For example, if you plan to spend your afternoon alone in a cozy chair reading a book, do you really need the entire house heated? Do you even need the entire room heated? Probably not. You’d be just fine if a source of heat were directed strictly at you and the rest of the room be dammed! But are there down sides to these devices? Aren’t there always?

Radiant heaters heat by directing energy (infrared radiation) at the person or object they are heating. Don’t worry, it’s completely safe radiation, not the kind that makes you glow in the dark. The down side is in the word “directing.” If you aren’t in a direct line, you don’t get the benefit. It’s like a flashlight beam in a dark room. If you’re in the path of the beam, you’re lit. If you aren’t in the path of the beam, you aren’t lit. There are some excellent model portable radiant heaters such as the Optimus H-5280 that get around this by oscillating much in the way some fans do, cycling back and forth. But, like an oscillating fan, you’re only enjoying the benefit when it is pointed directly at you.

Some portable radiant heaters can also rate lower for safety than, for example, an oil-filled heater. Think of these as a bit in the same category as halogen lamps in which a very hot element or bulb serves as an ignition risk should it somehow come into contact with a combustible. There are Mica and Ceramic models that up the safety margins notably such as those offered by Delonghi. Some Delonghi models offer additional bonuses such as bathroom water splash protection (imagine the pleasure of getting out of your shower on a cold winter’s day and still being toasty warm) and can even be wall mounted.

Finally, for the negatives and already pointed out, radiant heaters are not specifically meant to heat rooms but are designed to warm people and objects. If you want to keep a whole room warmed there may be other model heaters better suited to your needs. It’s important to note, though, that a radiant heater will (given time) heat a room simply because air flowing over the objects the heater has warmed up will also gradually warm up.

On the upside, portable heaters offer instant, directed heat to a person. They are great outdoor and semi-outdoor heating solutions in that cold air won’t simply blow the heat away (we love using ours for year around barbeque gatherings). Just don’t use them when it’s raining! They also offer very quiet operation which is a big plus to light sleepers. Used with a bit of common sense, radiant heaters can be a very cost effective way of keeping a person warm without wasting energy trying to heat an entire room or house. Their portability, small size options and quiet operation mean these are often the preferred under-the-desk heating solution for office workers.

If you are in the market for a portable heater and want something with a lot of pluses and very few downsides, radiant portable heating may well be a solution you shouldn’t overlook. For my money, it’s one of the smartest and most versatile heating options out there.

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Portable oil-filled heaters like the one pictured are wonderful devices. Unlike the kind permanently mounted in a home or apartment, these nifty options are completely enclosed and portable. No external plumbing connection required. A common mistake (not helped by the name) is that these devices aren’t really radiant heaters in the truest sense of the word. They are, in fact, convection heaters, relying on air currents to distribute the heat they generate. To minimize confusion, we’ll ignore that and continue to call them radiators. 

This is probably a good time to introduce you to our general ratings system. Let’s first emphasize the word general as some units in a particular category are going to score better or worse than others. An oil-filled portable heater without a tip-over cut-off, for example, isn’t going to be as safe as one with such a feature. The five elements of our ratings system are Economy (how much energy you can expect the unit to use), Safety (fire and burn hazards), Portability, Convenience (inconspicuous, attractive designs, etc) and Efficiency (purely a measure of how long it will take to heat a room). I think it’s important to note, though, that the Economy rating is difficult to quantify. Again, a well insulated room rapidly heated by a fan-equiped heater will retain that heat for a reasonable amount of time. That means less time operating the heater and, therefore, good economics. A passive heater in a poorly insulated room is going to take a long time to heat the room and will run almost constantly to maintain a comfortable temperature thereby drastically reducing any benefits in cost-savings it might otherwise afford. So, again, consider these ratings generalizations.

Oil-Filled Portable Heater Ratings

• Economy - High
• Comparative Safety - High
• Portability - Low
• Convenience - Moderate
• Efficiency - Low

 These portable heaters receive high marks when it comes to economy. Once heated, the oil they contain holds on to some of that heat meaning shorter durations of actual energy draw by the heating elements. In the world of portable heating, oil-filled heaters are the kings of cost-effectiveness. The lack of exposed heating elements and the incorporation of tip-over cut-offs also gives these models high marks in safety. With the application of common sense, they are a good option for a child’s room. 

Rankings start working their way down when it comes to convenience owing to the fact that oil-filled portable heaters can be comparatively bulky and are also fairly conspicuous. What keeps them from receiving a low rating is their silent operation which for light sleepers (this writer included) offsets any other potential drawbacks. 

Portability and Efficiency receive low marks. We want to emphasize this doesn’t mean these devices perform poorly in these categories, just that they don’t rank as high as they could relative to other options available. Liquid tends to be heavy and these are liquid filled so carrying one up and down stairs can be a nuisance. However, the inclusion of wheels means these heaters can easily migrate from one room to another if on the same floor. The low efficiency rating owes to these heaters relying on convection (the flow of air in the room) to move the heat they generate rather than on a built in fan. Again, quiet operation and low cost do a lot to offset this rating but, based purely on their ability to quickly heat a room, we felt a low rating was in order. If you are willing to turn the heater on 20-30 minutes before you plan on occupying the room, you’ll be fine. 

What you should know before you buy - Where possible, read consumer reviews on the oil-filled portable heater you are considering. Some models shipped, for example, have suffered from the way the company packages for shipping and consumers have reported devices with leaks. Ensure the manufacturer offers a convenient return or exchange policy including the cost of shipping. Also realize that the fins on oil-filled heaters become hot. Some designs take this into account, others do not making it difficult to move the heater from room to room without touching the hot fins. Note, however, that the heat is not so intense as to result in burns if contact is relatively brief (a couple seconds). 

Finally, some consumers have complained of a bad smell when first using their oil-filled heaters. It’s a not-uncommon lament but easily remedied. The smell is generally short-lived and can be eliminated by first using your heater in the garage or outdoors on a patio (providing there is no precipitation) for a few hours when you first use it. Yes, it’s a shameful waste of energy, but those with sensitive noses will do well to heed this advice. Do this for several hours when you first get the unit home and you’ll “burn off” the odor-causing agents for good. 

All things considered, oil-filled portable heaters are potentially one of the best options available. They are relatively cost effective, safe and good at the job providing you make allowances for how they work. If you don’t care about fan noise and want a near instantly heated room, this isn’t the model heater you need.

To get the most bang for your buck, start with the one element which will sabotage even the most efficient portable heater by thinking about insulation. Efforts here will save you money down the road regardless the heating solution you adopt. Failing to properly insulate your home or the room in which you will be using your heater is like opening a window and tossing some money into the wind every day. 

Next, get the right tool for the job. If you want instant heat cascading throughout the room a few minutes after you turn on your portable heater then you need a model with a fan to quickly move that hot air throughout the room. Realize right away that there’s a substantial drop off in savings by going for this option. Yes, your room will warm up more quickly but you’ll have to keep the portable heater on all day regardless and with a model that moves air, you’re operating both a heating element and a fan. More juice required equates to less money saved. For your real savings, opt for a passive portable heater. 

Passive portable heating models which radiate heat take longer to heat a room but offer the benefits of quiet operation and notable savings in heating costs due to the lack of an additional electric component to power. No fan. It’s important to understand what you’re getting here. You’ll want to turn the unit on thirty minutes or so in advance of expecting a cozy room. Options in this regard include radiant heat panels and oil heat. The latter look like common apartment radiators but are wheel-mounted and completely self-contained. 

Sticking with the right-tool-for-the-right-job motto, also ensure your heater is adequate for the space you want to heat. A heater designed for a 10 X 10 room isn’t going to be adequate for a 16 X 20 room with open doors. Read the specs before you buy and get what you need. Buying less isn’t going to save you more. You’re better off purchasing a heater designed for the space you are trying to heat and running it on lower power once the room is comfortable rather than buying two units which aren’t adequate for your space and running both on full power. 

Ultimately, your greatest savings in cost come from using your portable heater to warm the room you occupy and keeping your main central or gas heating unit turned down dramatically. In my own home, my wife and I often occupy separate floors of the house, her in her craft room, me in my office. We each have small, portable heaters for our separate rooms. As the rooms are fairly small, the heaters do a fine job on low settings. The remainder of the house is left comparatively cool giving our central heating and our checking account a nice break. 

By being sensible, using the right tool for the job, keeping our main heating unit set low and ensuring we have adequate insulation throughout our home, we realize savings in the range of several hundred dollars a year since adopting our own portable heating solution and you can too. Just ensure your portable heater is adequate for the job and use it where it will have the most effect.