How Long Does It Take to Fit a Boiler


The time it takes to fit a new boiler depends on a few different factors. It usually doesn't take long if you're replacing the same kind of boiler, otherwise known as a like-for-like boiler replacement. For example, if you're replacing your gas combi boiler with another energy-efficient one.

Overall, boiler installations can take anywhere from a couple of hours to a few days, depending on the location, fuel type and other factors.

In this article, we'll guide you through the process of getting a boiler replacement, including considering upgrades and relocating. We'll also briefly cover some extras you can add to your boiler and an efficient cleaning technique.

What affects how long it takes to install a new boiler?

The most efficient installations involve replacing existing boilers with new ones of the same kind while keeping the existing pipework. This is called a straight boiler swap and often takes around 4 to 6 hours.

However, if you want to move your boiler somewhere else, it might take longer. On average, changing the position of your boiler takes anywhere from 1 to 2 days. This is because, along with new pipework, you may also need new heating controls or a new boiler flue.

Installing a brand new combi boiler when you don't own one at the moment will also take 1 to 2 days for similar reasons.

Changing to an entirely new type of boiler will involve a lot of work, such as removing floorboards and some extensive pipework which could take a few days depending on the size of your property.

If you're changing the location and type of boiler, you can expect this to take longer to complete.

Read our article on the best type of central heating boiler to buy for more information.

Why you might need to replace your boiler

There are many reasons why you might want to replace your boiler, from upgrading performance to updating an older, less efficient model.

Did you know there are about 250 hospital admissions annually due to carbon monoxide poisoning in the UK?

Poorly maintained gas boilers could give off carbon monoxide, which is why regular boiler maintenance is so important. Regular boiler services allow you to address any issues, but also identify when you might need a new boiler.

You can easily replace most boilers as they are attached to the wall with a large bracket. Time is added if your flue goes through the roof due to the extra labour involved.

One aspect to consider is whether you have the right gas supply pipes in place. To comply with safety regulations, new standards detail that gas supply pipes must be at least 22mm in diameter instead of 15mm. This will add time to any gas boiler installation, and those with older boilers may not have regulation pipes.

Don't ever attempt to remove or replace your gas boiler yourself. Always hire a Gas Safe Registered Engineer to do it because of the risks involved.

Upgrading your boiler

Often, people are looking to upgrade from their old back boilers. Removing a back boiler can be difficult because they're often located behind a fireplace. The labour required to do these system upgrades takes time. They are also messy and quite expensive.

It'll typically take 2 to 3 days to upgrade your old boiler system to a new combi boiler or a gas system boiler.

Similarly, upgrading from an old boiler to a more modern, energy-efficient combi boiler will typically take about 2 days as it involves re-routing pipework, such as the boiler's gas supply pipe, and removing a water tank.

Changing boiler fuel types

There are many different boiler fuel types, but gas remains one of the most popular in the UK.

Other options include oil boilers, LPG boilers, and electric boilers. Unfortunately, if you're looking to change your current fuel type while keeping your boiler, that might not be possible. In this case, replacing your boiler is your only option.

Changing your fuel type may take 2 to 3 days to complete as there might be extensive electrical and plumbing work.

Relocating your boiler

Changing the location of your boiler could take a lot of time, and moving to a new area requires pipework rerouting, which costs both time and money.

You may also need to relocate the boiler flue. And moving your combi boiler elsewhere may take another half a day. There are lots of variables that could increase the amount of time the process takes.

Should you fit a new combi boiler?

Should you fit a new combi boiler

Compared to older boiler installations, a new combi boiler is a much better overall central heating system.

Combi boilers have quite a few positives:

They're compact - Compared to other boilers, they are more convenient. Additionally, they don't require a separate water storage tank. They get their water directly from the water mains.

  • More efficient than older boilers - New combi boilers get up to +/- 90% efficiency. They are much easier and faster to install than older boilers.

  • Fewer carbon emissions - Since they're so efficient, emissions are minimised. A few manufacturers have even created eco-friendly models that work better than the usual combi boilers.

    However, there are a couple of things to consider:

    Slower water rates - Because this boiler draws its water from the mains instead of a separate water tank, it may take longer to fill up a sink/bath.

  • Not as eco-friendly as heat pumps - Heat pumps use electricity and have the potential to be powered entirely by renewable energy, such as solar or wind power.

    You may also like: Combi Boiler vs Regular Boiler vs System Boiler: What's the difference?

    Other aspects to consider when fitting a new boiler

    There are processes you can do to improve the efficiency of your pre-existing system and extras you can include to enhance the lifespan of your new boiler.

    Power flushing

    Sometimes known as jet flushing, power flushing is a highly effective process of clearing build-ups in your current heating system. It works by dislodging these build-ups with a water treatment like a cleaning agent and high-pressure water. This method is often used with old boilers.

    Sludge, limescale, and rust can cause inefficiencies in your system and predispose it to breakdown. Some signs that you may need power flushing include:

    Your boiler or radiators are unusually noisy or make a noise that sounds like knocking. This is usually caused by blockages you can quickly resolve through power flushing.

  • Your water takes a while to heat up or doesn't get hot enough. Again, this is likely because of a build-up that is not allowing the hot water to be pumped correctly. A quick power flush can sort this right out.

    Typically, this process will take around 5 to 6 hours to complete, although in some cases, it could take longer.

    Smart thermostats

    Smart thermostat

    A smart thermostat lets you control your heating from your mobile phone or other handheld devices. These systems are relatively affordable and helpful when it comes to saving energy. They usually work on any installed boiler, but check with your manufacturer before presuming this. A registered professional will also usually be able to tell you.

    Installation of a smart thermostat will take roughly an hour.

    FAQs about fitting a boiler

    Can a plumber fit a boiler in a day?

    Yes, a plumber can fit a boiler in a day if it's simply replacing a pre-existing unit with a similar one. If you're opting to change the boiler you have or want to relocate it, it will take longer than one day. It may even take up to 3 days in some cases.

    How long does it usually take to replace a combi boiler?

    A combi boiler doesn't take very long to install, and a replacement combi boiler will take only 4 to 6 hours to install. However, replacing an older boiler with a combi boiler may take 1 to 2 days.

    What is the average lifespan of a boiler?

    The lifespan of your boiler depends on the specific type you have. Boilers can last anywhere from 10-15 years. However, this varies depending on how you maintain your boiler. For more information on how long boilers last, check out our other article!

    What does fitting a new boiler involve?

    Fitting a new boiler may include doing a power flush, reconfiguring the pipework, moving the old boiler and fitting the new boiler.

    Is it worth replacing an old boiler?

    Whether it's worth fitting a new boiler depends on whether there's a need for it. If you're still using an old inefficient system boiler or your boiler system is quite old and doesn't work well anymore, you should consider replacing it.

    Is replacing a boiler a messy job?

    Replacing a boiler can be quite messy, particularly if you're upgrading from an old back boiler, as this requires your fireplace to be removed to access it. Even installing a new combi boiler may cause messy surfaces.

    Will a new boiler make my house warmer?

    Yes, a new boiler may help keep your home warmer. Older boilers may not be as efficient, and this may be because of older technology or because they simply don't work like they used to. A new boiler almost always functions better than an older one.

    Find a new boiler with PlumbNation

    Choosing the right boiler to install can be daunting, but don't worry as PlumbNation are here to help! We have a wide variety of boilers, including oil combi boilers and electric combi boilers.