How Long Does It Take To Fit A New Boiler?

Fitting a new boiler or central heating system isn’t just complex and costly, it can be time consuming too. And let’s face it, nobody wants to live on a building site.

In this detailed guide we’ll explain exactly how long a boiler takes to fit as well as how much you should expect it to cost. 

We’ll cover common boiler installation work such as:

• Boiler swap
• Upgrade or conversion
• A new boiler in a new location
• A full central heating system installation

In Summary: How Long Does It Take To Fit a New Boiler?

Planning for your new boiler installation isn’t always possible. But if you can plan in advance, that’s what we’d suggest.

Gas engineers will need to be working on your property from 1-10 days depending on the type of installation they’ll be completing, which can be particularly disruptive for those working at home. 

Don’t have time to read this page in full? Bookmark it for later and read this summary instead.

Here’s how long a boiler takes to get fitted:

• A like for like boiler swap: 1 day 
• Upgrading to a new type of boiler (e.g. system to a combi): 2 days
• A full new central heating installation: 5-10 days
• Relocating your boiler (e.g. kitchen cupboard to a garage space): 1-2 days

No boiler replacement is the same, and here are just a handful of additional works that might add time onto the overall installation:

• Updating your gas supply to meet current Gas Safe regulations: 4-6 hours
• Replacing your hot water cylinder or cold water storage tank: 1-2 days
• Power flushing your radiators and pipework: 3-6 hours
• Installation of new heating controls and radiator valves: 1-6 hours

How Long a Boiler Replacement Takes

Boiler Swap: 1 day

A straight boiler swap is the quickest, easiest and cheapest type of boiler work you can have completed in your property. Expect a typical boiler swap to take approximately 4-6 hours for a relatively simple replacement, or, up to a day if there are a few complexities. 

The work involved here is incredibly straightforward, given the pipework and connections are already in place. A Gas Safe registered engineer simply needs to turn off the gas and electricity supply, remove the old boiler and fit your new one. 

Typical costs associated with a boiler swap of this kind, assuming you have a combi, are in the region of £2,250-£3,000. The price variation here is due to a few things including any extra fittings or pipework that might need to be upgraded or replaced, as well as the type of boiler you choose.

If you’re looking to have a new boiler fitted to an old system like we mention here, you can get your fixed price on-screen by clicking through to our boiler installation page. 

Upgrade / Conversion: 2-3 days

A much larger job than a straight boiler swap is an upgrade or conversion. There are three main types of boilers:

• Combi - heats on-demand and therefore, has no need for a hot water cylinder or cold water storage tank
• System - uses a water cylinder to store hot water
• Conventional (heat only) - uses both a hot water cylinder and a cold water storage tank (usually located in a loft space)

Changing your heating system from any one of the above systems to another is a lot more complex than simply swapping the same boiler for another (for instance, changing an old combi for a new one).

As an example, if you’re going from a system to a combi boiler, a lot of the existing heating setup will need to be removed (such as the hot water cylinder) and pipework capped off. 

Due to each boiler upgrade or conversion being so vastly different, how long they take to fit will vary a lot too. Typically, you’d expect an upgrade or conversion to be in the 2-3 day range to be on the safe side. 

Given how much extra time these types of installations take in comparison to a normal boiler swap, expect the cost to spike too. Typically, you’d be looking at around £4,500, although that price depends on the specific job. 

You can read more about boiler installation costs here, or jump over to our clickable boiler quote form to get an exact (and fixed) price on screen within a couple of minutes. 

New Central Heating System Installation: 5-10 days

If you’ve moved into a property with no central heating or have completely ripped it out to make way for a new one, this is the biggest and most costly installation job. 

This is going to mean running and installing the pipework from scratch, installing and connecting up the boiler, fitting a magnetic system filter, radiators, radiator valves, boiler controls and so much more. 

So how long does it take to fit a new central heating system? A job of this size is going to take 5-10 working days, so up to 2 weeks in total. 

In terms of cost, there are simply too many variables that affect an individual installation to be able to give an accurate price estimation without going into huge detail. 

However, if you’re in an average UK property (3-bedroom semi detached) expect costs to sit somewhere in the £5,000-£8,500 range. 

Moving Your Boiler to a New Location: 1-2 days

Moving a boiler to a new location is usually an option if you’re wanting to free up some space in the room it’s currently fitted in. For example, moving your boiler from a kitchen cupboard into a neighbouring garage space. 

The work involved with a job like this includes everything mentioned in the boiler swap above (1 day), plus a further 1-2 days. This allows your Gas Safe engineer time to run pipework, water and electricity to the new location. 

The biggest factors here that affect the time taken to fit your boiler in a new location include: 

• Distance to the new location - the further away the new boiler needs to be installed, the more pipework that has to be fitted and potentially, more holes drilled to run pipework through walls.
• Flue core hole - To fit the flue in the new location, a core hole will need to be drilled through an external wall. Depending on the type of brick (or sometimes, thick stone in old cottages), this could add hours onto the job

A simple boiler relocation could be as cheap as £750. However, really complex jobs could be as much as £1,500.

Additional Work That Can Add Time to a Boiler Replacement

The timescales we explain above for the new boiler to be completed is for an “average” installation. 

No single heating system is the same. Any additional work or complexity involved with a boiler replacement is going to mean the boiler takes longer to get fitted and naturally, that’s going to add to the cost. 
Below are a few common examples of work / complexities that add time and money to the cost of an install. 

Not sure if any of these apply to your property? Let our clickable boiler installation specification form remove all the confusion and get a fixed price for your new boiler on screen within 2-minutes. 

Upgrading Your Gas Supply: 4-6 hours

If you’re not in a property that was built in the last decade, it’s likely the gas supply / heating pipes are not currently up to Gas Safe standards. 

Where this is the case, parts of the gas supply and pipework will need to be upgraded to larger bore. This extra work is going to mean that it takes longer to fit your boiler; usually an extra couple of hours to a half day’s worth of work. 

And like any extra work, it’s likely to cost in both labour and materials; somewhere in the region of £300. 

Not sure if you need your gas supply upgrading? You can speak to our boiler advisors using our contact form. 

Hot Water Cylinder / Cold Water Tank Replacement: 1-2 days

As we mentioned above, there are 3 main types of boilers: combi, conventional and system. 

Work involving combi boilers is usually the quickest. That’s because system and conventional boilers use a combination of hot water cylinders and / or cold water storage tanks. 

The timescales mentioned above don’t account for removing old hot water cylinders / cold water storage tanks or replacing these units and the necessary pipework. If you do need a new cylinder or cold water storage tank, this could add up to 2 days onto your installation’s timeline.

Power Flush: 3-6 hours

Power flushing used to be incredibly popular, and is sometimes still recommended. However, it’s typically only suitable for newer systems. Older systems with old and weak soldered joints simply won’t hold up during a power flush.

A power flush uses a combination of pressure and chemicals to break down heating sludge (rust from the inside of pipework and radiators). Sludge build ups can cause boiler breakdowns such as a burnt out heat exchanger (a costly repair), or radiators not getting hot. 

Power flushing generally takes 3-6 hours, a lot of that being the time taken to drain down the system and refill it. 

A quicker, safer and cheaper option to a power flush, is a chemical flush. This doesn’t put as much strain on old / weak joints in an old central heating system, but achieves a similar result.

New Heating Controls or Thermostatic Radiator Valves: 1-6 hours

If you’re replacing your tired old boiler with a new one, it’s worth spending the time to upgrade smart heating controls and thermostatic radiator valves. 

Depending on the smart controls and rad valves you choose, this is likely to add 1-6 hours onto the overall installation time of your new boiler.

‍