New Boiler Cost and Installation in 2025 (London Guide)

What Does a New Boiler Cost in 2025?

Let’s start with the bit everyone asks first. Based on the work we’ve done this year, the cost of a boiler replacement in London – that’s the boiler itself plus installation – usually lands between £2,300 and £4,800.

These prices cover everything from simple combi swaps in one-bed flats through to full upgrades in busy family houses. Prices can vart on job but from our experience most do fall in the range listed above.

These figures are based on real invoices from 2025, not guesswork from a price comparison site. Your own boiler cost and installation will depend on how straightforward the swap is, what needs upgrading and which boiler you go for.

If you’d rather not play “how much will it be?” in your head, you can send us a couple of photos and get a price based on your actual setup.

Who’s Behind This Guide?

We’re ARA Services Ltd, a small London firm that looks after heating, plumbing and electrics. Every engineer is Gas Safe registered. If you every cant get in contact with us their is a directory of engineer on Gas Safe Register.

Most days we’re somewhere along the North Circular, cutting across to Stratford, dropping into Brixton or working near Enfield Town. Over the years we’ve seen hidden pipework in Victorian basements, tight cupboards in tower blocks and just about every “creative” DIY job you can imagine.

This page is simply us writing down what we explain in people’s kitchens while their old boiler cools down. No script, no sales chat – just how it works and what it tends to cost in real life.

Boiler Cost by Type: Combi, System, Regular, Back Boiler & Electric

Once you have a rough idea of the price range, the next step is working out which kind of boiler actually suits your home. Here’s how the main options work out on the ground.

Combi boiler cost – the usual option

In London, most replacements we carry out are combis. If you live in a flat or smaller house and don’t have everyone showering at once, a combi boiler is often the neatest solution. No tanks, no cylinder, less to go wrong.

• Combi boiler price: £900 – £1,800 depending on brand and size
• Labour, pipe tweaks and controls: usually £1,200 – £2,000

Put together, the normal cost to replace a combi boiler comes in around £2,300 – £3,800. Straight swaps in the same spot are towards the lower end; moving the boiler or sorting out awkward access pushes it up.

If you’re still trying to get your head around what a combi actually costs (because every website seems to say something different), I’ve put together a simple breakdown here — real numbers, not those “from £999” adverts you see everywhere. You can see it on our combi boiler installation prices page . It basically shows what people around London are genuinely paying in 2025, not fantasy internet prices.

System boiler cost – for bigger hot water demand

A system boiler works with a hot water cylinder. It suits homes with more than one bathroom or where people often run taps and showers at the same time.The Energy Saving Trust has good infortmation on running cost for a variety hesting systems If you already have a cylinder in place, it can be a tidy way to upgrade.

• System boiler unit: around £1,200 – £2,000
• Fitting and linking to the cylinder: £1,400 – £2,500

Most system boiler jobs we do land between £2,800 and £4,500. The higher end usually means older pipework, a cylinder swap or more involved controls.

Regular (heat-only) boiler cost – keeping an older layout

Regular boilers (also called heat-only or conventional) are the ones that work with tanks in the loft. They’re not fashionable, but some larger or older properties are set up around that system and still run well on it.

• Regular boiler: roughly £1,000 – £1,800
• Labour, flushing, dealing with tanks and controls: £1,900 – £3,000

So the total boiler and fitting cost usually sits somewhere in the £2,900 – £4,800 range.

Back boiler replacement cost – retiring the firebox

Back boilers live behind gas fires and most of them are now well past their best. You can’t install a brand new back boiler in 2025, so a “back boiler replacement” really means removing or making safe the old unit and putting a modern boiler somewhere more sensible.

• Remove or make safe the back boiler and gas fire
• Fit a combi or system boiler in a new position, often kitchen or loft
• Run a suitable flue, upgrade the gas pipe if needed and sort new controls

Because there are a few stages, this sort of replace boiler cost is higher than a simple swap. Most we do end up between £3,200 and £5,200, depending on access, pipework and how much making good is needed afterwards.

Electric boiler cost – for all-electric homes

In smaller flats or places without gas, an electric boiler can be a practical choice. Upfront costs aren’t miles away from gas, but the running cost depends heavily on your electricity tariff, so it’s worth doing the sums first. The Energy Saving Trust has good plain-English info on running costs for different heating systems.

• Electric boiler: roughly £900 – £1,600
• Installation and electrical work: usually £1,500 – £2,400

Total boiler replacement cost for an electric boiler is normally around £2,400 – £4,000. If you’re weighing up gas vs electric, our guide on gas vs electric boilers and running costs is a good place to start.

Real Boiler Pricing Examples from London Jobs

Looking at prices on a chart is one thing, but most people want to know what these jobs actually look like in real homes. Here are a few typical examples from work we’ve done around London recently — nothing fancy, just the kind of jobs we see week in, week out.

What’s Included in Every ARA Boiler Installation

However simple or involved the job turns out to be, there are some things we always include so you know exactly what you’re paying for:

• Old boiler safely isolated, disconnected and taken away.
• New boiler mounted, levelled and connected to existing or upgraded pipework.
• Gas supply checked and upgraded if needed to meet current standards.
• Flue installed and sealed in line with manufacturer instructions and Gas Safe rules.
• System filled, vented and tested for leaks.
• Heating and hot water controls set up and explained in plain language.
• Benchmark logbook completed and the installation registered with Gas Safe.
• Here is a Clear explanation of the warranty and how to keep it valid so your boiler is protected..

To ensure all info is correct , you can always take a quick look at guidance on the Gas Safe Register or on the government’s GOV.UK site.

What Actually Affects Boiler Replacement Cost?

When you search for “new boiler how much” or “boiler replacement cost UK” you get a huge range of prices. The difference in price usually is efected by these details.

1. The types of boilers :combi, system, regular, electric, or a back boiler conversion.
2. Boiler size in kW: small flat vs busy family home with several bathrooms.
3. Boiler location: simple like-for-like in the same cupboard, or moving it to a loft or utility room.
4. Flue route: short horizontal run vs long or awkward vertical flue.
5. Gas pipework: older homes often need the gas pipe increasing in size to meet current rules.
6. Condition of the system: clean water vs heavy sludge – sometimes a powerflush is the only sensible way forward.
7. Controls: basic thermostat, programmable timer or a smart system such as Hive or Nest.
8. Access and parking: loft hatches, top-floor flats, stairwells and parking all affect how long the job takes.
9. Paperwork: Gas Safe notification, building regulations, and landlord certificates for rentals.

How much is the installation part on its own?

For a straightforward job, the cost of installing a new boiler (labour only, not including the boiler itself) in London is often in the £1,000 – £1,700 range.

As a rough idea of time on site:

• 1 day – simple combi-to-combi in the same place.
• 1–2 days – combi conversions or regular-to-system upgrades.
• 2+ days – back boiler conversions or bigger system overhauls with cylinder work.

Every gas boiler we fit is installed and signed off by a Gas Safe registered engineer. Once the work is finished, we register the installation and you receive the confirmation for your records. If you’re thinking ahead, our guide on how often to service your boiler explains how to keep it running safely and efficiently.

Extras That Can Change the Final Price (And Often Save Hassle Later)

When we talk about the full cost of boiler replacement, it isn’t only the box on the wall. A few sensible extras can protect the boiler and help the system run better for longer.

None of these are forced on you. We’ll tell you what’s genuinely worth doing in your property and what can wait, so you’re not paying for extras just for the sake of it.

The Govererment offersd Boiler Grants for certain households.

I would reccomend that you check if your are elligible before paying full price for a boiler replacement yourself, it’s worth checking whether any help is available. Schemes change, and not everyone qualifies, but now and again they can take a decent chunk off the bill.

Things that often matter for eligibility include:

• How old and inefficient your current boiler is.
• The type of property you live in and how well it’s insulated.
• Income or benefits for certain schemes.
• Whether you’re moving to a more efficient heating setup.

The government’s Boiler Upgrade Scheme and other support are explained on GOV.UK, and the Energy Saving Trust often has up-to-date round-ups of grants and insulation help.

We keep an eye on what’s running and can usually say quite quickly if it’s worth you chasing anything. We won’t promise a grant if there isn’t a realistic route – you’ll simply get a straight answer.

Why People Around London Choose ARA for Boiler Work

Loads of companies will happily sell you a boiler. The difference, really, is the service. Most people just want someone who answers the phone, turns up when they say they will, and explains everything in straight, simple language.

• Gas Safe engineers only: every boiler we fit is installed and signed off by someone properly qualified — no shortcuts.
• Local knowledge: we know the usual problem spots around London — tight basements, awkward access, busy streets and those roads where parking is a nightmare.
• Clear pricing: we put everything in writing so you know exactly what you’re paying for, without any last-minute surprises.
• Experience: we’ve been repairing, servicing and installing boilers across London for more than ten years, and there’s not much we haven’t seen by now.
• Guaranteed work: you get all the right paperwork, plus a real person to call if you’ve got questions or something doesn’t feel right later on.

Little stories from recent jobs

One review came from a customer who rang on a Monday with no hot water. By Saturday she had a new boiler and a shower fitted. We looked at some photos she sent, talked through two or three options and booked the work around her shifts. What she liked most was that everything was explained in straightforward terms, not boiler jargon.

Another review mentioned a boiler that “wasn’t working and the engineer managed to fix it on the first visit”. That was a small flat on a noisy main road – we traced the fault, replaced a part and had the heating back on the same afternoon. No new boiler that time, just a sensible repair and honest chat about how long the old unit was likely to last.

We also heard from a customer whose back boiler finally gave up. They wrote about how we helped them choose a new boiler, fitted it at a fair price and took everything away – old boiler, old fire and all the rubbish – so they weren’t left with a pile of scrap outside.

If you’re a landlord, the paperwork can feel like a separate job. Our guides on what a Gas Safety certificate is and selling a house without a Gas Safety certificate go through the basics in simple terms.

A Few Words from Our Customers 5★ average from dozens of Google reviews

We could talk about ourselves all day, but the reviews give a better feel for how we work. Here are a handful, shortened slightly for length but kept true to what people wrote.