Radiators

Radiators divide into two questions: how much heat you need, and how much wall you can give it.

Compact panel radiators

The workhorse. Panel radiators are classified by type, which describes how many panels and convector fins they have:

• Type 11 — single panel, single convector. Slimmest at around 50mm deep, lowest output.
• Type 21 — double panel, single convector. Around 70mm, moderate output.
• Type 22 — double panel, double convector. Around 100mm, and typically double the output of a Type 11 the same size.

If wall space is tight, a Type 22 gives far more heat from the same width than a Type 11 — at the cost of projecting further into the room.

Designer, vertical and horizontal

Vertical radiators use height instead of width, which suits narrow walls and hallways. Designer radiators trade some efficiency for appearance. Horizontal models suit rooms with limited wall height, typically under a window.

Sizing it properly

Work out the room's requirement in BTUs rather than matching whatever was there before — insulation, glazing and extensions all change the answer. An undersized radiator will never warm the room however long it runs.

Quoted outputs assume a 50°C temperature difference. If your system runs cooler, as heat pumps do, expect meaningfully less than the rated figure.

Valves are separate

Almost all radiators are supplied without them, and you need a pair. Check where your pipes emerge before choosing angled, straight or corner — see our radiator valves.

Looking to warm towels? See towel radiators.