New boiler installation and gas boiler replacement

Updated November 2026

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What a new boiler installation involves

For most homes, a new boiler installation and a gas boiler replacement are the same job. The old boiler comes out and a new one goes in, usually in the same place.

Here’s how it works with us:

1. Get a fixed online quote, then choose a boiler and a date.
2. Send photos of your boiler and pipework after you order. There’s no home survey.
3. A Gas Safe engineer fits the new boiler, takes the old one away, flushes the system, and shows you the controls.

If the new boiler goes in the same place and is the same type, that’s a like-for-like swap, which is the most common job. Changing the type, or moving the boiler to a new position, is a bigger job and takes longer.

You see the price before you pay. Nobody needs to visit first, and we won’t call you to get the quote started.

When you need a gas boiler replacement

It may be time to replace your gas boiler if it keeps breaking down, it’s leaking, it’s old, your heating bills have been climbing, or repairs are becoming frequent. If the boiler has failed, a like-for-like swap is often the straightforward option. A repair can still be the right first step if the boiler is otherwise sound, so use the guide below if you’re unsure.

For a fuller look at repair versus replacement, see our guide to when to replace your boiler.

How much a new boiler installation costs

New gas boilers are supplied and fitted from £1,790 (prices vary). In November 2026 our online quote shows:

• Combi swap from £1,928.99
• Regular boiler swap from £2,820
• System boiler swap from £3,094
• Regular-to-combi conversion from £2,628.99

Each of those is a from-price, and prices vary. See this month’s list on our boiler prices page. For what drives the figure, read the new boiler cost guide.

A change of type, or moving the boiler, costs more than a like-for-like swap. The online quote gives you the fixed price for your home.

See prices for my home

How long it takes

A like-for-like combi swap usually takes 4 to 6 hours. If you order by 3pm, and the job, stock and postcode allow, it can be next day. That applies to like-for-like combi swaps, not every job.

System and regular like-for-like swaps usually take longer, and they are not next-day jobs. Conversions, for example changing from a regular or back boiler to a combi, commonly take around two days. Moving a boiler also adds time.

The dates you can book appear on your quote. For the next-day rules, see next-day boiler installation. For more on timings, see how long it takes to fit a new boiler.

What’s included

The prices on the quote are fixed, include VAT, and cover:

• A new gas boiler, supplied and fitted by a Gas Safe engineer
• Your old boiler taken away
• The flue and the pipework needed for the job
• A chemical flush, inhibitor and magnetic filter
• A wireless thermostat (you can add a smart thermostat at checkout)
• A 12-month workmanship guarantee
• The manufacturer guarantee, which is up to 14 years depending on model. Your quote shows the exact guarantee for the boiler you pick
• Building-control notification and the paperwork after the install

Not included, if needed: asbestos removal, and scaffolding or special access.

Which type of boiler you need

A short guide is enough here. The type you have now is often the type you should keep, unless you want to change how your hot water works.

• Combi boilers heat your radiators and your hot water from the mains, with no cylinder. They suit most homes with one or two bathrooms.
• System boilers store hot water in a cylinder, so two showers can run at once if the cylinder is the right size. They are not next-day jobs.
• Regular boilers, sometimes called conventional or heat-only, use a cylinder and a cold tank in the loft.

If you’re choosing between a combi and a system boiler, see system boiler vs combi boiler.

Boilers we fit

We fit gas Worcester Bosch, Viessmann, Alpha and Ideal boilers. You can compare types and packages on our new boilers page, or read the reviews and prices for Worcester Bosch, Viessmann, Alpha and Ideal.

We install across England, Scotland and Wales, including boiler installation in London and Leeds.

How the quote works

You get a fixed price online at our quote. There’s no home survey. After you order, you send photos of your boiler and pipework so the engineer arrives prepared.

For how the online quote works, see new boiler quote online.

If you want a lower-cost option, see cheap boiler installation. To see how buying online with installation works, see buy a boiler online.

Flexible ways to pay may be available at checkout. There’s a short guide to paying monthly if you want to read more first.

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FAQs

How much does a new boiler installation cost?

New gas boilers are supplied and fitted from £1,790, prices vary. In November 2026 our online quote shows combi swaps from £1,928.99, regular boilers from £2,820 and system boilers from £3,094. See this month’s boiler prices. Your own fixed price is on the online quote.

How much does a gas boiler replacement cost?

For most homes a gas boiler replacement is the same job as a new installation: the old boiler comes out and a new one goes in, usually in the same place. The same from-price applies, from £1,790, prices vary. A change of type costs more than a like-for-like swap. Get a fixed price on the online quote.

How long does a boiler installation take?

A like-for-like combi swap usually takes 4 to 6 hours. System or regular swaps take longer and are not next-day jobs. Conversions, such as changing from a regular or back boiler to a combi, commonly take around two days. Moving a boiler also adds time. There’s a longer timings guide if you want more detail.

Can I get a new boiler fitted next day?

Often, for a like-for-like combi swap, if you order by 3pm and the job, stock and postcode allow. System jobs and conversions are not next-day. Your quote shows the dates you can book. The next-day installation page has the full rules.

Do I need a home survey?

No. You get a fixed price online and send photos of your boiler and pipework after you order, so the engineer arrives prepared. Nobody needs to visit your home to give you the price, and the figure you see is the price for the job as quoted.

What’s included in a boiler installation?

The new boiler, Gas Safe fitting, your old boiler taken away, the flue and the pipework the job needs, a chemical flush, inhibitor and magnetic filter, a wireless thermostat, a 12-month workmanship guarantee, and the manufacturer guarantee shown on your quote. Scaffolding and asbestos work, if needed, are not included.

Do I need a Gas Safe engineer, and do I get a certificate?

Yes. Only a Gas Safe registered engineer can legally fit a gas boiler in the UK. After the install, the work is notified to building control and you get the paperwork. This is included in the quote, so you don’t arrange it separately.

Can I fit my own gas boiler?

No. It is illegal and unsafe to fit a gas boiler unless you are Gas Safe registered. A neighbour or a general tradesperson cannot do this work legally if they are not on the register. There’s a short guide on whether you can install a boiler yourself if you want to read more.

What if I want to change from a regular or system boiler to a combi?

That is a conversion, not a like-for-like swap, so it takes longer and costs more. It is not a next-day job. In November 2026 our quote shows a regular-to-combi change from £2,628.99, prices vary. The online quote gives your own fixed price, and there’s more on regular boilers and combi boilers.

Can I spread the cost?

Flexible ways to pay may be available at checkout. Your options appear when you complete the quote, and you can see them before you place the order. There’s a short guide to paying monthly if you want to read more first.

Get a fixed online price

When you’re ready, get a fixed price for a new gas boiler installation or a gas boiler replacement. There’s no survey, and you choose the date that works for you.

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