Radiator Installation and Replacement

A towel rail on the central heating only warms up when the heating is on. A dual-fuel rail adds an electric element so it can be used in summer. The element needs a suitable electrical supply, installed through our domestic electrical installation service and certified through one of the routes the building regulations allow; bathroom electrical zones apply.

The right size depends on the room's heat loss, not just its floor area. Radiator output is listed in watts or BTU (British thermal units). To size a radiator properly, we look at:

• The room: Floor area and ceiling height.
• Heat loss: The number of outside walls, the size and type of windows, insulation, and whether the room is above an unheated space.
• How warm the room should be: Living rooms and bathrooms are usually kept warmer than bedrooms and hallways.
• The flow temperature of your system: Manufacturers typically quote output at a high water temperature (known as ΔT50). If your boiler runs cooler, for better efficiency, or you plan a heat pump, the real output is lower and a larger radiator is needed.

Online BTU calculators give a rough starting point; for a whole house, a room-by-room heat loss calculation is more reliable. We will tell you if a room needs a bigger radiator or a second one.

Radiator replacement is the simplest version of the job when the new radiator has the same pipe centres (the distance between the two valves) as the old one, so the existing pipes line up. If the new radiator is wider, narrower or a different style, we adjust the pipework or use extension tails so the valves line up neatly.

Replace rather than repair when a radiator has pinhole leaks from internal corrosion, is too small for the room, or is cold in places even after it has been flushed. If the problem is a single fault, such as a stuck valve, a cold top or a leaking spindle, our radiator maintenance and repair service may save you a new radiator. If several radiators are cold at the bottom, the system may need power flushing before new radiators go in, so they are not filled with old sludge.

Every new radiator is fitted with new valves. Normally that means a thermostatic radiator valve (TRV) at one end, which controls the temperature of that room, and a lockshield valve at the other, used to balance the system. The room with the main room thermostat, often the hallway, is usually fitted with a manual valve instead of a TRV, so the two controls do not work against each other.

You can choose standard TRVs, or smart TRVs that set a schedule for each room from an app. These are installed through our thermostat and heating control installation service.

Yes. Moving a radiator means extending or rerouting the flow and return pipes to the new position:

• Along the same wall: Usually a short extension of the pipes under the floorboards.
• To another wall: The pipes may run under a suspended timber floor, or be chased into the wall or boxed in where the floor is solid concrete.
• During a renovation or extension: The best time, as pipes can be run before floors and walls are finished, as part of a full house renovation or house extension.

Narrow microbore pipework can limit how much heat a larger radiator gives, so we check pipe sizes first. Any channels or holes are made good afterwards, and our painting service can finish the wall.

Radiators are traditionally fitted under windows to counter cold draughts, which still suits older homes; well-insulated rooms give more freedom. Avoid positions where sofas, beds or long curtains will block the heat, and check the wall can take the weight, especially for column and cast iron radiators on stud walls, which may need extra timber supports.