Water Heater Installation London — All Types Covered

For a gas-connected London flat, a combi boiler is almost always the right choice — it provides both hot water and heating, is highly efficient, and requires no storage space for a cylinder. For a flat without mains gas, an electric storage water heater (or electric combi unit) is the typical solution — sized based on how many people are in the flat and peak demand. For a single-bathroom flat on Economy 7, a 125L electric storage heater charged overnight provides sufficient hot water for most households at reasonable cost.

Costs depend on the type. An electric point-of-use heater (under-sink) installs for £150–£400 including a standard unit. An electric storage heater installs for £350–£600 including unit. A gas multipoint heater installs for £600–£1,200 including unit. A full combi boiler installation is £2,200–£3,200. All prices include Gas Safe certificates where applicable and a 30-day workmanship guarantee.

A multipoint water heater is a gas or electric appliance that heats water on demand (like a combi boiler) but is separate from the central heating system. It supplies hot water to multiple outlets (bath, basin, kitchen) without storing it in a cylinder. Gas multipoints are popular in bedsits, studio flats, and commercial applications where a full combi boiler installation is impractical. Modern gas multipoints are condensing units with efficiency up to 80–85%.

For a London flat without mains gas, your options are: (1) Electric storage water heater — stores and heats water electrically, runs overnight on Economy 7 tariff for lower cost. (2) Electric combi unit — provides both hot water and space heating electrically (expensive to run, but all-in-one). (3) LPG or bulk gas (only relevant if storage is possible — rare in London flats). (4) Air source heat pump — significantly more efficient than resistive electric heating, eligible for Boiler Upgrade Scheme (BUS) grants. We assess the most cost-effective option for your specific flat and usage.

Yes — under-sink electric water heaters (and over-sink models) can be installed in bathrooms, provided they are in the correct Zone as defined by BS 7671 (IET Wiring Regulations). The wiring and installation must be carried out by a Part P registered electrician. We coordinate the electrical element with a qualified electrician when installing bathroom water heaters to ensure full compliance.

An under-sink electric water heater installs in 1–2 hours (plus electrician time for wiring). An electric storage water heater in a cupboard takes 2–4 hours including pipework and pressure testing. A gas multipoint water heater takes 2–4 hours including flue fitting and gas connection. A combi boiler installation takes 6–8 hours (one day). We provide a specific time estimate when we quote.

No planning permission is required for water heater installation. However, all gas appliance installations require a Gas Safe registered engineer and a Gas Safe completion certificate (mandatory by law). Unvented hot water cylinder installations require Building Control notification under Part G3. We handle all required notifications as part of our installation service.

A point-of-use (POU) water heater is a small electric heater installed directly at the outlet — under the sink, over the basin, or in a cupboard near a single tap. It's ideal for: a cloakroom far from the boiler where hot water takes a long time to arrive through the pipe run; an outdoor tap; a garden room or garage; or an additional basin added to a property where running hot water pipes would be disruptive. Sizes typically range from 7L to 30L. Running cost is higher than gas but negligible for occasional use.

Yes. Back boiler removal is a Gas Safe notifiable job that we carry out regularly in London — they're particularly common in 1970s–1990s terraced houses. A back boiler removal typically involves removing the gas fire and boiler, capping the gas supply (or rerouting it for a new boiler), removing the flue and sealing the chimney breast opening, and installing a new combi boiler with new flue and all pipework connections. This is usually a 1–2 day job depending on the property.

For most London properties with gas supply and central heating, yes. A combi boiler is more efficient than a separate water heater (especially replacing an old non-condensing multipoint), provides both hot water and heating from one unit, and avoids the standing losses of storage cylinders. The only situations where a standalone water heater makes more sense are: single-room applications without central heating; properties without gas supply; supplementing a combi in distant outlets; or outbuildings where running gas pipework is impractical.