How long does it take to fit a boiler?

What factors affect boiler installation time? 

In some cases boiler installation can take a few hours, especially if you’re replacing the old one with something similar. In other cases it can take a few days. Either way, boiler installation time differs due to certain factors that come into play.

The type of boiler you’re installing 

A combi boiler can take a few hours to install but a biomass boiler can take up to 2-3 working days. Either way, your boiler type influences installation time as some are bigger or more complicated than others.

The size of your property and its layout

A larger property (with multiple bathrooms and radiators) requires a larger boiler so that the property stays properly heated. And a larger boiler takes longer to install than a smaller one purely due to its size. 

Your existing boiler system

A like-for-like combi boiler installation can take up to 6 hours. But, if you’re converting from a conventional boiler to a combi, it can take up to 2 days. This is due to pipework or extra components that are needed. 

Pipework and system upgrades

A new boiler may involve new pipework around the house, removal of floorboards and other system upgrades. This can take a few days depending on the size of your property. 

How long does boiler installation take? 

Installation time can differ for each boiler type, especially if you’re getting an entirely new system. 

How long does it take to install a combi boiler? 

A combi boiler provides heating and hot water on demand. There’s no need for separate hot water cylinders or tanks, which saves space and also cuts down installation time. 

If you’re replacing an old combi boiler with a new one, it will take around 4-6 hours to install. But if you’re moving boilers and putting a new combi boiler somewhere else, it can take up to a day and a half. 

How long does it take to convert to a combi boiler? 

If your old boiler was a system or conventional boiler, and your new one is a combi boiler, installation can take up to two days. 

Tank removal and pipe installation is likely to happen on the first day and then the new boiler can be installed on the second. 

How long does it take to install a conventional boiler? 

A conventional boiler – also known as a heat-only boiler – requires both a hot and cold water storage tank in order for it to work. It’s a bulky system that requires a lot of space so installation time is likely to take 1-3 days. 

How long does it take to install a system boiler?  

A system boiler can take 2-3 days to install. This is because it features a water cylinder that needs to be fitted into the property. 

Hot water cylinders are usually fitted into an airing cupboard or near the boiler. When it’s installation time, new pipework has to be installed and the floorboards need to be raised so that work can be carried out. 

How long does it take to convert a conventional boiler to a system boiler? 

It takes 2-3 days to change from a conventional boiler to a system boiler. 

A conventional boiler uses a water cylinder (like a system boiler) but also requires a cold water storage tank. So if you’re converting to a system boiler, engineers will remove the water storage tank as it’s no longer needed.

How long does it take to install a biomass boiler?  

Biomass boilers can be installed in around 1-2 days. They may be expensive to install (between £8,000-£15,000) but they tend to have a longer lifespan (20-30 years). 

How long does it take to install a boiler and upgrade your central heating system?  

A new boiler and additional upgrades to your central heating system are likely to take a few days depending on what needs adding/removing. 

If you live in a larger property, it could take a few days to install new radiators into each room. Some plumbers and heating engineers say it can take a full day to replace three radiators. 

You might also choose to install smart technology, which helps you control your heating from anywhere and save on your energy bills. Smart thermostats like a Google Nest can be installed in less than an hour, but don’t forget to make the engineer aware of the job. It’s also a good idea to ask for a demonstration of how the smart controls work.

What is the boiler installation process? 

From pre-installation checks to the actual boiler installation, here’s what the process involves: 

1. Site survey

An engineer (at your request) might survey your existing heating system. This helps ensure the boiler you choose is appropriate and can help spot anything that might impact installation. Always look for a Gas Safe-registered engineer as only they are legally allowed to install boilers.

2. Removing the old boiler

The engineer carefully disconnects the boiler from the gas and water pipes and removes it from its mount. They can also take the old boiler away for - often at no extra cost. In some cases, old boilers - or their parts can be recycled.

Once your old boiler has gone, the system will be flushed out and cleaned so that there’s no debris stuck in the old system. Ask the engineer to check with the boiler manufacturer before installation to find out if this is required.

3. Fitting the new boiler

Your new boiler is mounted into the spot requested, then connected to the radiators and gas and water supply. The engineer may also connect it to the hot and cold water storage tank depending on the type of boiler it is. 

The engineer will take time to ensure all components are properly aligned so this could take a few hours. If you want to change the location of your boiler, this will take longer. 

4. Installing a filter

If you’ve opted for a magnetic filter system, it will be installed now. A filter helps your boiler last longer by collecting debris and sludge that builds up over time, preventing blockages as a result. Read more about how to prolong your boiler’s life.

5. Testing and commissioning the new boiler

Once the new boiler is installed, the engineer will test the system and check for leaks to make sure everything’s working properly. This may involve checking all radiators and taps are working properly. They will also check your water pressure.

6. Handover of your new boiler

As a final step, the engineer will complete a handover, explaining how the new boiler works and answering any questions you have. This is your chance to read the instruction manual and find out how to operate the boiler and carry out basic checks. At this point you can also schedule your annual service.

What can extend boiler installation time? 

Everyone wants boiler installation work to be carried out as quickly as possible, but in some cases it can take longer than expected. 

Here are the main causes of long boiler installation times:

• Difficult-to-access boiler location – if the boiler is located in a tight space or somewhere that’s hard to access, installation could take extra time. Always make engineers aware of the boiler location beforehand and let them know if it’s easy or difficult to access.
• Pipework issues – new water or gas pipes may need to be installed for the boiler, or adjustments may be needed to existing pipework which adds time. It can also involve lifting up floorboards. This can apply if your existing heating system is over 15 years old. If a new pipe is not fitted, your new boiler will not be safe to use and will not pass building regulations.
• Additional upgrades – if you choose to install a smart thermometer or controls, the engineer may need an extra hour or so.

How to prepare for a new boiler installation

If you want boiler installation to be carried out quickly, there are two important things you can do beforehand to help speed up the process. 

1. Clean up – make sure there’s nothing in the way of the boiler so that the engineer has a clear path and it’s easy for them to work.
2. Turn the gas and water valves off –  turn off your gas and water supply before the new boiler is installed and be prepared to deal with no water or heat for a few hours. Put some water in kettles or fill up buckets if needed. Because you’ll be without heating, it makes sense to get your new boiler installed in the summer if possible.