Radiators and heating

For a cold radiator, a weeping valve, a new radiator or a set of thermostatic valves, you want a plumber or heating engineer who does central heating work. For anything on the gas side of the boiler you need a Gas Safe registered heating engineer, and a good firm will say plainly which of the two your job is. Many heating plumbers and heating engineers are the same people wearing different hats, so the useful question is not the job title but what the registration covers.

This page explains what radiator and heating work involves, what you can safely do yourself, where the legal lines sit and what the published savings figures say about controls.

Who to call for a heating problem

The split follows what is being touched.

• Water-side work: radiators, radiator valves, pipework, towel rails, pumps, motorised valves, thermostats and programmers. A competent plumber can do this. No gas is involved, so Gas Safe registration is not the deciding factor, though a firm that does both will usually hold it.
• Gas-side work: the boiler, its burner, gas pipe, flue and gas valve. HSE says anyone employed to work on gas appliances in domestic premises must be Gas Safe registered and competent for that type of work. The back of the engineer's ID card shows what they are qualified to do.
• Boiler replacement or a new heating system: this is a bigger job and has its own pages for boiler installation and boiler repair.

If you are unsure which category a fault falls into, describe the symptom rather than guessing the cause. Ask a registered engineer to diagnose it. Our guide on checking a plumber's registration shows how to confirm who is on the books.

Common radiator and heating jobs

One radiator cold at the top, warm at the bottom. This usually points to trapped air, and bleeding the radiator with a key often fixes it. Many householders do this themselves. If the pressure on a sealed system drops afterwards, the system needs topping up using the filling loop, and a heating engineer can show you how.

Cold at the bottom or in the middle, warm at the top. That pattern often suggests debris in the system. A flush may be needed, and our page on power flushing explains when it is worth it.

A radiator that stays cold while others get hot. Check the TRV pin first, since a valve can stick after a summer shut off. If the pin moves freely, the cause may be a blocked radiator, a balancing problem or a seized lockshield valve.

Radiators that heat unevenly, with distant rooms slow to warm. Balancing adjusts the lockshield valves so hot water reaches every radiator in proportion. It takes time and some trial and error, but it is a routine visit.

A leaking valve or radiator. Isolate the radiator if the valves allow it, shut off the heating and call a plumber. Water on carpet and floorboards causes damage fast, so an urgent call is reasonable.

Noises. Banging, gurgling and ticking come from air, scale, flow noise or pipes expanding. A plumber can narrow it down by listening at the pump, the valves and the radiator.

Replacing, moving or adding radiators. This means draining part or all of the system, fitting new valves, reconnecting and refilling with inhibitor. A like-for-like swap is quick. Moving a radiator or adding one means new pipework, floorboards up and, sometimes, a check that the boiler and pump can supply the extra load.

Towel rails and bathroom radiators. These tie into the same system or an electric element. See our notes in bathroom fitting.

What heating controls can save

Controls are the part of a heating system where published figures are easiest to find. The Energy Saving Trust says installing and using heating controls effectively could save around £100 a year in Great Britain. It lists the controls central heating should have as a programmer, at least one room thermostat and thermostatic radiator valves, plus a cylinder thermostat if there is a hot water cylinder.

For homes that already have a programmer and thermostat, adding TRVs saves less: the Trust puts it at £30 a year in Great Britain. It puts the cost of adding TRVs to all radiators at around £370, and at around £600 for a programmer, thermostat and TRVs where none are fitted. These are estimates for typical homes, not quotes. A larger house or a long run of old radiators will cost more.

Behaviour matters as much as hardware. The Trust says most people are comfortable between 18°C and 21°C, and that turning the thermostat down from 22°C to 21°C could save around £120 a year in Great Britain. On a TRV, it suggests the lowest setting that keeps the room comfortable, such as 3 to 4 in rooms you use most and 2 to 3 in bedrooms.

Two practical points follow. First, TRVs and a room thermostat need to work together, and a heating engineer can check that one is not fighting the other. Second, if your boiler has a flow temperature setting, ask the engineer about it. The Trust notes that if the flow temperature is not set high enough in very cold weather, your home may not reach a comfortable temperature, so ask the engineer to set it correctly.

Rules and paperwork

Replacing radiators or valves on an existing system is generally low-risk work, while new heating systems and boiler replacements are covered by the Building Regulations. Our guide to building regulations for plumbing and heating sets out which jobs need a notice, and which need a registered competent person to sign them off.

If you are a landlord, remember that gas appliances need an annual check by a registered engineer, and the record goes to your tenants. See the landlord gas safety record guide. For owner-occupiers, HSE strongly advises that gas appliances, flues and pipework are serviced at least annually by a Gas Safe registered engineer.

If you are considering moving away from gas, the Boiler Upgrade Scheme in England and Wales offers a grant of £7,500 for an air-to-water heat pump in a home that is not off the gas grid, according to the Department for Energy Security and Net Zero notice effective from 21 July 2026. The notice sets different values for other cases, so check the current terms before you commit.

What affects the cost

We do not publish prices here, and the directory has no listed prices to draw on. Quotes for heating work differ because of:

• the number and size of radiators involved, and whether the system needs draining down in full
• the type of system, since a sealed system with a combi boiler is different from a vented system with a cylinder
• pipework condition, access under floors, and whether it is concealed
• the valves and controls you choose, from basic TRVs to programmable or smart units
• the age of the radiators, and whether old valves will seize when moved
• call-out outside normal hours, which is why a pre-winter check is often cheaper than a January emergency

Ask for the quote to list each radiator, valve and control by name.

How to choose and check a heating plumber

1. Ask whether the work is on the water side, the gas side or both, and what registration the firm holds for each.
2. Check the registration, using the guide linked above. For gas, look at the back of the ID card, not just the front.
3. Get a written quote that states what happens to the old radiators, what inhibitor is used and whether any chemical flush is included.
4. Ask who will balance the system and whether they will leave the settings written down.
5. Check what guarantee applies to the labour and to the parts.

Our directory lists registered businesses and orders them by verified reviews first and then distance, with no paid placement in the ranked list. You can browse plumbers by city to see who works in your area.

Before the cold weather

Autumn is the sensible time to find out whether the system copes. Bleed radiators, check each TRV pin moves, look for damp patches below valves, and listen to the pump. If something is wrong, an engineer can plan the repair before the first cold snap, rather than at the busiest point of the season. If a boiler stops altogether or you smell gas, do not wait, and use our emergency plumber page or the gas emergency number.