Stelrad Compact K1 60 section radiator 450 x 2000mm

Panel radiators are pressed steel radiators that heat a room using hot water from the central heating system. They are made with one, two or three panels, with or without convector fins behind, in a wide choice of heights and lengths.

Radiator types

• Type 11 (single convector, SC or K1): one panel with one set of fins, and the slimmest of the common types.
• Type 21 (double panel plus, DPX or P+): two panels with one set of fins, giving more heat while staying slimmer than a type 22.
• Type 22 (double convector, DC or K2): two panels and two sets of fins, for more heat from the same wall space in larger or colder rooms.
• Triple panel: three panels, the deepest of these types.

Sizing by heat output

Choose a radiator by its heat output in watts, worked out from the heat loss of the room. Outputs are tested to BS EN 442 and quoted at delta T 50, the UK standard for gas boiler systems, which assumes 75°C flow, 65°C return and a 20°C room. A system running at a lower water temperature, such as one with a heat pump, gets less heat from the same radiator, so check the output at delta T 30 or 40 and size up where needed.

Fitting

Check the height, length and pipe centres against the space and the existing pipework, and allow room for the valves at each end. Fit a thermostatic radiator valve on one end and a lockshield valve on the other. In England, when a boiler is installed or replaced, Approved Document L expects thermostatic radiator valves on every radiator except in the room with the main room thermostat.

For radiator valves, see thermostatic radiator valves; for towel rails and other styles, see radiators and accessories.