How to Choose Between a Type 21 and a Type 22 Radiator

Most radiators work through a mix of either electricity, boiling water or oil-based systems. These radiators heat up the room due to the radiators themselves heating up and radiating (it’s in the name) the warmth through the spaces they’re placed in. 


Not convector radiators though. Whilst it’s true that they do use the above power inputs to generate heat, they work in a slightly different way to your everyday radiator. Furthermore, there is a wide range of different types, each utilising different aesthetic aspects to deliver heat in a way that suits different households or properties. 


With both internal and external variations, as well as a wide range of different materials being used in their building, it can all get a little complicated. That’s why we’ve broken down the two main types of convector radiators for you. 


Whether you own stainless steel or aluminium radiators that uses convection to generate heat, this short guide to the Type 22 and the Type 21 will no doubt clear things up a little. 


Convectors: type 21 and type 22

Convection Radiators

Convection radiators work slightly differently to normal radiators. Using a range of internal and external components, the convector radiator transfers heat through a cycle of warm and cold air. As the warm air rises from the radiator, it transfers through space and eventually cools down and lowers. This air is once again recycled through the radiator and rises again as warm air.  

How Do They Work


A convector radiator is kitted out with a differing number of external, hollow panels and convector fins between them. These convector fins can come in a range of different shapes but are designed to distribute air evenly into space.  

Type 21


Type 21 convector radiators have two panels, one facing the wall and one facing out. Inside these are one set of convector fins. The hollow panels produce heat via either electric power or through the central heating. The convector fins are usually zigzag-shaped and line the inside of the radiator.


Type 22

The difference between Type 22 and Type 21 convector radiators is that in Type 22 radiators, there are two sets of convector fins inside the radiator. These obviously push out more heat and are thicker than your average Type 21 radiator.


Designer Radiators Direct 

Telling Them Apart


The subtle differences in convector fins can make telling these units apart difficult. 

The best way to remember which type is which, is to think of their numerically driven names not as full numbers, but as two-two or two-one. The two represents the number of panels, whilst the one represents the number of convector fins. 

It should also be noted what a convector radiator looks like in general. These are usually horizontal radiators, not vertical radiators, and are often characterised by their white panels.

What’s Best for Your Home?

Panel radiators suit every home due to their sleek subtlety, but knowing which type will suit your property is a different question altogether. 

Type 22

Type 22 radiators are thicker than Type 21. The reason for this is that they have two sets of convector fins, thus taking up an inch or so more in diameter. This makes them better suited to larger spaces that need more power to be heated. More is always better when it comes to home heating, capitalising on the extra fins with no extra power used. This is especially important in a draughty space like a hallway or large living room.

Type 21

Type 21 produces less heat but takes up less space. This makes them far better for well insulated, but smaller spaces. If you’re trying to be economical about the floor space being taken up, then opt for a type 21 convector radiator. 

Need help deciding which style suits your home? 


Now that you know the difference between Type 21 and Type 22 radiators, you’re in a great position to make a purchase. If you would like further assistance in choosing the best radiator for your home, don't hesitate to get in touch with us. 

Give us a call on 01257 758 247 or send an email to Alternatively, you can fill out and submit your query to us using our online contact form.

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