Panel Radiator Types 10, 11, 21, 22 and 33 Explained

Steel panel radiators are commonly identified by a two-digit type number. The first digit indicates the number of water-carrying panels; the second indicates the number of convector layers attached behind those panels. Understanding this system makes catalogue comparisons much easier.

What each panel radiator type means

Type 10

Type 10 has one heating panel and no convector. It offers the slimmest projection and a simple, easy-to-clean form. Output is lower than finned versions of the same height and length, so it is best where wall depth and hygiene are more important than maximum capacity.

Type 11

Type 11 combines one panel with one convector. It remains relatively slim while gaining useful output. This format is widely used in apartments, bedrooms and general residential programmes.

Type 21

Type 21 uses two panels with one convector. It can be a good middle ground when a buyer wants more radiant surface than Type 11 without the full depth of Type 22.

Type 22

Type 22 has two panels and two convectors. It is one of the most frequently specified formats because it delivers strong output across a broad range of standard sizes.

Type 33

Type 33 combines three panels and three convectors. It provides high output from a shorter wall length, but the greater depth and weight must be considered during layout, transport and installation planning.

How to choose for a product range

Do not select only by type number. Compare certified output at the same temperature condition, available heights and lengths, total projection, brackets, connection options, packaging and the expectations of the destination market. A focused range often uses Type 11 for slim applications, Type 22 for the core offer and selected Type 33 sizes for high-demand rooms.