heating
Central heating installation and repair
A full central heating system in a three-bedroom house costs £3,500 to £7,500 including the boiler, radiators, pipework and controls. Extending an existing system to a new room is usually £400 to £900 per radiator.
What this covers
What it costs. A full central heating system for a three-bedroom house costs £3,500 to £7,500 including the boiler, radiators, pipework and controls. Full cost breakdown.
What the job covers
- Full system installations in properties with none
- Extending heating to an extension or loft conversion
- Repiping in plastic or copper
- Zone valves, controls and thermostats
- System balancing and cold radiator diagnosis
What is involved
A heating system is sized before it is priced. A room by room heat loss calculation gives the output each radiator needs in watts, and the sum of those, plus the hot water demand, gives the boiler output. Systems installed without that calculation are typically oversized, which costs more to buy, more to run, and makes the boiler cycle on and off instead of running steadily at condensing temperatures.
Pipework is either copper or barrier plastic. Copper is used where pipes are visible and where the run is exposed to heat. Plastic is quicker under floors and through joists, and is normal in modern installs, but it needs proper support and inserts at every joint. A new system in an occupied house is usually run in a mix: plastic in the floor voids, copper for tails and anywhere on show.
Controls have changed what a good system looks like. Building regulations now expect time and temperature control with room thermostats and thermostatic radiator valves as a minimum, and weather compensation or load compensation on new installs. The practical effect is a system that runs at a lower flow temperature for longer, which is both cheaper and kinder to the boiler than short blasts at 80 degrees.
A cold radiator at the bottom is sludge; a cold radiator at the top is air. Radiators that never warm at all, at one end of the house, usually mean the system was never balanced, and balancing is an afternoon with a thermometer rather than a new pump.
Full system installations in properties with none, one of the jobs a central heating specialist is hired for.
Choosing someone for the job
Ask for the heat loss calculation, not just a boiler size. Ask what flow temperature the system is designed around, because a system designed for 50 degrees needs bigger radiators than one designed for 75 and is far cheaper to run. Ask whether the quote includes a magnetic filter, an inhibitor dose and a commissioning and balancing visit.
Common questions
How much is a new central heating system?
£3,500 to £7,500 for a three-bedroom house with a new boiler, radiators, pipework and controls. Larger properties and systems needing a cylinder run higher.
Can I add a radiator to my existing system?
Usually yes. The question is whether the boiler and pipework have capacity. One extra radiator is normally fine; heating a whole extension may not be.