Balance your radiators so every room heats evenly

Use this guide if some radiators get hot quickly while others, usually furthest from the boiler, stay lukewarm even after bleeding. You need a radiator bleed key, a lockshield key or small adjustable spanner, a notepad, and ideally a cheap clip-on or infrared thermometer.

Step by step

1. Rule out the simple causes first

   Bleed every radiator and check the boiler pressure is in the range shown in its manual, because air and low pressure mimic a balancing problem. Feel each cold radiator: cold at the top but warm at the bottom means air, cold at the bottom but warm at the top usually means sludge, which balancing will not fix. If only one radiator is cold everywhere, check its valves are actually open before going further. Only move on when radiators are bled, pressure is correct and the issue is uneven heat between rooms.