Choosing The Right Type of Radiator

There is the option to go either horizontal or vertical when buying a radiator, with a huge range of sizes available here at Trade Radiators.

And while getting a unit at the right height and with its key it’s also worth considering the type of radiator, as different types can be suited to different room sizes.

This is because the type of radiator can have an impact on its heating capabilities, for example, a 400 x 600 Type 11 radiator won’t have as much output as a Type 22 radiator that’s the same size.

This guide will focus largely on Type 11, Type 21, and Type 22 radiators - all available in different heights and widths.

With our radiator size chart and accompanying table, you'll gain a better understanding of the differences between these, and how to find a type of radiator that works for your space.

We have also included a full radiator size chart, covering all the widths and heights that you can choose from across our full range of radiators, at the end of this post.

Different Types of Radiators

There are three types of radiators, each designed to suit different room sizes and heating needs. The right choice depends on your Delta T value, available space, and required heat outpu. Using our provided tables below can help you come to a decision when looking at these radiators in particular.

Type 11 (K1)

A Type 11 radiator features a single panel with one set of convection fins, making it the most compact option. It is ideal for smaller rooms, such as bedrooms or home offices, where heat requirements are lower.

They are available in various widths and heights that typically fit smaller spaces. They generally protrude 70-80mm from the wall, keeping a slim profile. 

Browse Our Type 11 Radiators

Type 21

A Type 21 radiator has two panels and one set of convection fins, which strikes a good balance between heat output and space efficiency. This makes it ideal for medium-sized rooms like living rooms and dining areas. 

Wider and taller options are available to accommodate different room layouts. Typically extends 90–100mm from the wall, maintaining a sleek design.

Browse Our Type 21 Radiators

Type 22 (K2)

A Type 22 radiator consists of two panels with two sets of convection fins, making it the most powerful option. It is best suited for larger or colder rooms, such as hallways, open-plan spaces, or areas with higher heat loss.

Comes in a range of larger dimensions for maximum heat output. Extends 120–130mm from the wall due to its extra depth.

Browse Our Type 22 Radiators

Determining Your Heat Requirements

To choose the right radiator type for your room, you need to understand your room’s heat requirements. 

We have helpful tools on our site to aid with this. A key part of this is calculating your Delta T value, as it determines how much heat your radiator needs to produce.

Delta T Conversion

Delta T refers to the difference between the average temperature of the water circulating through your heating system and your desired room temperature. 

For example, if you want your room at 20°C and the water temperature in your radiator is 70°C, the Delta T would be 50°C (70°C - 20°C).

We have made this easy to calculate with our Delta T conversion table. 

A higher Delta T indicates a greater heat output needed to maintain the desired room temperature. 

Use our BTU Heating calculator to determine the necessary heat output (measured in BTUs or kW) based on room size, insulation, and other factors. 

Choosing Your Radiator Type

Your Delta T value is one of the factors that helps you decide which radiator type is best for your space. 

If your room is small or well-insulated, a Type 11 radiator should provide enough heat. For medium-sized rooms, a Type 21 offers a good balance. If you’re heating a large space or an area with high heat loss, a Type 22 will provide the most warmth. 

Once you've determined your Delta T value, refer to our radiator size chart, and the accompanying table below, which provides the necessary outputs based on varying Delta T values for different room sizes.

By cross-referencing your Delta T value with the chart, you can easily find the radiator that will deliver the optimal heat output for your space. 

Need assistance in choosing? Contact us today.

Radiator Size Chart

For some inspiration on choosing the right radiator for your living space, take a look below at some fantastic photos submitted by our customers. You'll find a wide variety or rads and aesthetics, so hopefully you'll be inspired to get the perfect radiator or heated towel rail for your home!