how do convection heaters work

How do Convection Heaters Work?

How do convection heaters work? In this article, we’ll take a look at that. After reading this short convection heater guide, you’ll understand how convection heaters work. In my explanations, I’ll stick to a very intuitive level. Let’s just avoid the detailed physics. We all had enough of it in school.

Here’s the short answer: Convection heaters work using a heating coil that produces hot air. The hot air is then distributed by a fan or by a large metal surface. Convection heaters use the air as a medium to transport the heat. Either they heat up air and then blow it across the room to distribute it. Or they make use of the natural rising of warm air, which ensures that the heat distributes itself. Keep reading to find out more.

How a convection heater works: The Basics

Convection heat is not hard to understand. Convection is the scientific term for “movement of air” (or any other gas). So, convection heat is all about heating a room using the natural movement of the air.

As you might already know, air rises when it’s warm and drops when it cools down. So, when you have a convection heater in your room, it will pull the cool air and pass it over a hot metal coil to heat it.

Convection heaters oftentimes use a fan to draw in the cool air and push it out when it is warmed up. But not all types of convection heaters work this way. For example, there are oil-filled radiators that warm the air using their big metal surface. The hot air rises naturally and doesn’t need to be pushed.

But when you get a convection heater with a built-in fan: Great. A fan increases the heating speed.

As you see, it’s easy to understand convection heat.

Difference between convection heating and radiant heating

To understand convection heating even better let’s compare it with radiant heating. Both types of heating are very popular. Here are the key differences:

Heating speed

Radiant heaters work in a completely different way than convection heaters. They don’t heat the air. They use radiation to heat up objects directly. The heat is transferred using radiation instead of convection.

That’s why radiant heaters are much faster than convection heaters. They don’t heat the air first. They heat the object they’re pointed at directly and immediately.

In contrast, convection heaters are a little slower. To heat a room, they first need to heat the air in that room. As a result, radiant heating is better if you want quick heating.

But if you don’t care about whether your room is warm within a minute or five, then convection heaters are fine.

Heat Retention

Convection heaters heat the air. That’s why when you turn them off, the air will stay warm for a few more hours. Obviously the heat doesn’t disappear right away.

In contrast, infrared heaters lose their heat nearly immediately after you turn them off.

So, if you want to have a heater that can keep your bedroom warm overnight, then a convection heater is the better choice. It retains the heat for much longer.

Efficiency

Convection heaters and radiant heaters are efficient in different scenarios. Each type of heater is very efficient if you use it the right way.

Infrared heaters are most efficient if you use them to heat just certain spots in a room. Radiant heat is directional heat, so you can influence where the heat is going. That’s why infrared heaters can keep you warm in a very large room. Because they don’t use any energy for heating the whole room, but just the spot where you are.

Infrared heat is 40% more efficient than any other type of heater when you want to heat only certain spots in a room (e.g. you and your spouse on the living room couch).

Meanwhile, convection heaters are much better for keeping a whole room warm. Convection heaters heat the air in the whole room and the natural movement of air ensures that the heat reaches every corner.

That’s why convection heat is best for heating whole rooms.

Comfort

There’s even a difference in comfort when you pick radiant heat instead of convection heat. When you use an infrared heater, the heat feels like the sun is shining on your skin. However, the side of your body that’s facing the heater is warmer than the opposite side.

Convection heaters distribute their heat evenly and that’s why I find them much more comfortable.

Some people say convection heaters dry out the air. And yes, it’s true in some way. By heating the air, the relative humidity drops and the air feels drier. But you can easily compensate for that. Check this article to learn how: 3 Space Heaters that don’t dry the air

Noise

Convection heaters have to distribute the heat using convection. Oftentimes, to speed up the heating, they come with a built-in fan that blows warm air into the room. That is one of the reasons convection heaters are among the loudest heaters. However, oil heaters or other convection heaters which distribute the heat using the natural rising of warm air, don’t cause any noise. Because they don’t have a built-in fan, they are the quietest space heaters.

As you see, with convection heaters you get many choices. Either you pick models with a fan which oftentimes gives you faster heating speeds but more noise. Or you pick a model without a built-in fan that heats a little slower, but absolutely quiet.

In contrast, infrared heaters are mostly quiet. But when they run on full power, they can also produce noise. Infrared heater use infrared heating elements to produce radiant heat. If they run on lots of power, they can start buzzing or humming.

If you need an absolutely quiet heater, oil heaters (which belong to the group of convection heaters) are always the best idea.

Light

Some heaters produce light. Especially infrared radiant heaters. They usually heat using infrared heating tubes. To produce the heat, these heating tubes first have to heat up to a point where they glow red.

So, all radiant heaters glow.

an infrared space heater on the floor stairs

In contrast, convection heaters oftentimes don’t. Yes, there are some convection heaters where you can see a glowing hot heating coil. But mostly the heating coil is hidden inside the body of the heater.

So, if you want to heat overnight, and you prefer to have a dark room, then stick with convection heaters. They heat “invisibly”.

“Convection heaters are popular for when instant heat is required, as they quickly create a warm air current that can be felt the moment the heater is switched on.”

electricradiatorsdirect.co.uk

Types of convection heaters

Generally, four different types of heaters belong to the group of convection heaters.

  • Wall-mounted convection heaters for your home: Mostly for bedrooms and other living spaces. Wall-mounted convection heaters, like panel heaters, are often used for whole-room heating or even commercial applications.
  • Portable or wall-mounted heaters with built-in fans: Portable space heaters are heaters you can place anywhere you like. Oftentimes they’re a temporary heating solution. Wall-mounted heaters are more of a permanent heating solution. But basically, they’re just the same as portable space heaters, except you mount them to a wall. The heat is still produced within the heater and not by a central heating system.
  • Oil heaters: Oil heaters distribute the heat using a large metal surface. The oil acts as a heat reservoir and retains the heat, so it keeps heating even after you shut it off. Oil heaters are among the safest types of heaters.
  • Central furnace heaters: Central furnace heaters are all heaters that don’t produce heat on their own. They are connected to the central heating system using pipes or ducts, which supplies the central heaters with hot water or gas. Central heating can be powered by different energy sources: Mostly they are either gas, fuel or oil.

Conclusion: How do Convection Heaters work?

Convection heaters make use of the natural movement of hot air. They are, in fact, one of the most intuitive ways to heat. It’s similar to when people heated with fires (which is radiant heat), and then they found out that you can heat much more efficiently using a wood stove (which is convection heat).

Convection heaters are a very basic approach to heating. But that’s a good thing. They are less prone to errors and they are very cost-effective. Convection heaters also come in all shapes and sizes. From big tower heater that heats entire living spaces to small desk heaters that keep just your hands warm.

Because convection heaters are easy to produce they are also very affordable.

Now, let’s check out the Recommended Products page. You’ll find the single best heaters of each category.

Attributions: Title image by Aaron Yoo (CC BY-ND 2.0)

About the Author

Daniel Hirsch

Daniel is an electrical engineer, blogger, and author. He studied electrical engineering and information technology and decided to blog about heaters after working in the temperature sensing industry.