Radiator Installation Across the UK

Not by law. Radiators are part of the wet central heating system, not the gas supply, so a competent heating engineer or plumber can replace them. Any work on the boiler, gas valve or gas pipework must be done by a Gas Safe registered engineer, so if the job involves the boiler as well, make sure that part is done by someone on the Gas Safe Register.

It depends on the room's size, how well it is insulated, how many outside walls and windows it has, and the temperature you want it. A heat loss calculation, or a reputable online BTU calculator, gives the output needed in watts or BTU per hour. As a rough guide, a small bedroom often needs around 2,000 to 3,500 BTU and a living room 5,000 to 8,000 BTU, but older, draughty or north-facing rooms need more.

Often, yes. If the new radiator has the same pipe centres as the old one, the existing valves and pipes can be reused or only slightly adjusted. Radiators come in standard sizes, so a like-for-like match is usually easy to find.

A like-for-like swap usually takes one to two hours. Several radiators, new positions or pipework changes can take a full day or more, and replacing every radiator in a house typically takes one to three days.

Usually. Radiator outputs are normally quoted at a high flow temperature, and a heat pump runs much cooler, often around 45 to 50°C. At those temperatures a radiator gives out roughly half of its quoted output, so some rooms need larger or double-panel radiators. A heat loss survey shows which rooms need upgrading.

Yes. TRVs let you set each room to a different temperature, so you are not heating spare rooms or bedrooms more than needed. They are recommended on most radiators, except usually the one in the room with the main thermostat, and are expected when boilers or heating systems are replaced.

Inhibitor is a chemical added to the water in a central heating system to slow corrosion and the build-up of sludge inside radiators, pipes and the boiler. Whenever the system is drained, it should be refilled with the correct dose of inhibitor.

Plug-in electric radiators do not, but fixed electric radiators and towel rails wired into the mains should be installed by a competent electrician. In England and Wales, work such as a new circuit or certain work in bathrooms is notifiable under Part P of the Building Regulations.