How do I find a good boiler installer near me?

Choose a local, Gas Safe registered company that surveys your home before quoting, includes a system clean, gives a fixed price and offers its own workmanship warranty. Reviews from customers in your area are a good sign that the company looks after people after the job is done.

Should I replace my boiler or repair it?

If the boiler is reliable and the repair is minor, repairing it is usually better value. If it breaks down repeatedly, is inefficient, or the repair costs close to a new boiler, replacement usually works out cheaper over the next few years.

Can I keep my existing radiators with a new boiler?

Usually, yes. Existing radiators can normally stay, as long as the system is cleaned and any leaking or seized radiators and valves are dealt with. Your installer should check them during the survey.

Boiler installation near me: a guide for West and South West London homes

By Swift 24-7 Plumbers · Updated 5 November 2026

Engineer connecting copper pipework to a newly installed combi boiler

Replacing a boiler is one of the bigger jobs in a London home, and the choice of installer matters as much as the choice of boiler. This guide explains how to pick the right type of boiler for your home, what a proper installation includes, how long it takes, and the questions to ask before you sign a quote.

Start with the right type of boiler

There are three main types of gas boiler, and the right one depends on your home rather than the brochure.

Combi boilers heat water on demand from the mains, so there is no hot water cylinder and no loft tank. They suit flats and houses with one bathroom, which covers a large share of the conversions and terraces in Putney, Fulham, Wandsworth and Brixton.
System boilers heat a stored hot water cylinder fed from the mains. They suit homes with two or more bathrooms where several people shower at the same time, such as larger family houses in Wimbledon, Richmond and Teddington.
Regular boilers work with a cold water tank in the loft and a hot water cylinder. They are often the simplest replacement in older houses with gravity-fed pipework.

A combi is not automatically the best choice. If your home has two bathrooms and a busy morning routine, a combi can struggle to supply two showers at once, and a system boiler with a cylinder will be more comfortable.

Bigger is not better: why sizing matters

An oversized boiler costs more to buy and switches on and off more often, which wastes gas and wears components. A good installer sizes the boiler from your home's heat loss and hot water demand. Ask how the size in your quote was worked out. If the answer is "it's the same as the old one", that is worth questioning, because many homes have had insulation, glazing or extensions added since the last boiler went in.

What a proper boiler installation includes

A survey of the heating system, gas supply, flue route and condensate drain.
A clear, fixed quote that lists the boiler, controls, any pipework changes and the system clean.
Cleaning the heating system with a chemical clean or power flush, adding inhibitor, and fitting a magnetic filter. Sludge from an old system is the most common reason new boilers fail early.
Compliant controls, including a programmer and room thermostat that meet current Building Regulations.
Commissioning, including flue gas readings and the Benchmark checklist.
Paperwork: notification to Building Control through Gas Safe, and registration of the manufacturer guarantee.

How long does a boiler installation take?

A straight swap in the same position usually takes one day. Moving the boiler, converting a regular system to a combi or adding a cylinder usually takes two to three days, because pipework, the flue and sometimes the gas supply need to change. Your installer should confirm the timescale in writing, so you know how long you will be without heating and hot water.

Questions to ask before you book

Are your engineers Gas Safe registered, and will the installation be notified to Building Control?
Is the system clean included, and will you fit a magnetic filter?
How did you size the boiler?
Is the price fixed, and what would make it change?
What warranty do you give on your own workmanship, separate from the manufacturer guarantee?
Who do I call if something goes wrong in the first year?

Boiler installation with Swift 24-7 Plumbers

Swift 24-7 Plumbers installs combi, system and regular boilers across South West and West London, from our base in Putney. Every installation is surveyed first, quoted at a flat rate, cleaned and protected with inhibitor, and covered by our 12-month workmanship warranty. Read more about our boiler installation service, or call 020 4572 3451 to arrange a survey.