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Best Boiler Warranty UK Lengths & Boiler Guarantees

Boiler warranty & guarantee guide – Who offers the best boiler warranty?

A new boiler is a big outgoing and one that should give you many years of reliable hot water and heating. But we all know that from time to time, things break down.

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If the thought of labour costs and callout charges causes you a sense of panic, then the boiler warranty is there to prevent all of that stress and worry.

Having a warranty on your new boiler means that you can relax safe in the knowledge that if there is a problem, then you’re covered.

However, not all warranties from all boiler manufacturers are created equally.

There can be huge differences in the length of the warranty offered on a brand new boiler between different boiler brands, whether that’s Ideal boilers or Glow Worm. In fact, some companies don’t offer a warranty; they provide a guarantee instead.

In this guide, we’re going to take you through everything that you need to know about the boiler warranty.

We’ll take a look at the difference between a warranty and a guarantee and the terms and conditions you should be aware of to keep your warranty/guarantee valid.

Then, we’ll check out what’s on offer by the different best boiler manufacturers included their extended warranty offers.

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What is a boiler warranty?

8 year boiler warranty

When a boiler manufacturer offers a warranty on their boiler, they are essentially making a promise that they will repair your boiler for a set period of time following its installation.

The length of the boiler warranty varies from one manufacturer to the next and even with their own range, there can be huge differences in what’s on offer.

What is a boiler guarantee?

There are a few boiler manufacturers who have decided to offer a boiler guarantee rather than a boiler warranty. Now, many people use those terms interchangeably but a guarantee is different from a warranty.

Here are the key differences:

Enhanced rights under consumer law

The first key and important difference between the two is that a guarantee is legally binding. That means that it strengthens your rights under consumer law.

Cover for the whole boiler

boiler parts

Have you ever tried to claim under a car warranty only to be told that the very thing that’s causing a problem isn’t covered?

That can be exactly the same issue with boilers when covered by a warranty. The boiler manufacturer may decide to exclude some key components such as the heat exchanger from the cover.

Guarantees cover the whole product. So no matter the problem that consumers may have with Worcester Bosch boilers, they will fix the boiler free of charge during the warranty period.

Call out charges

Under boiler warranty terms, the manufacturer can charge you a call-out fee. That can be an unexpected and unpleasant cost when you thought that you had manufacturer cover through the warranty.

Worcester Bosch makes no charge for their call-outs under their guarantee, as long as you have had your boiler serviced annually.

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Terms and conditions of boiler warranties

All boiler warranties will have terms and conditions that must be met in order for there to be cover. And that’s no matter the type of boiler, they still apply whether you have a system, regular or combi boiler.

Do remember as well, that there is unlikely to be cover for the entire heating system it does just cover the boiler. The most common requirements to keep the warranty valid are:

Installed by a Gas Safe engineer

Correct installation is essential for a new boiler to run efficiently. Not only that, but in the UK it’s a legal requirement that a gas boiler installation is only carried out by a qualified and gas safe registered engineer.

When heating engineers make mistakes during the installation process, not only can it be highly dangerous but it can cause excess wear and tear to the boiler components.

Annual servicing is carried out by a Gas Safe engineer

Just like all mechanical devices, over time, a boiler will begin to run less efficiently. When you have your boiler serviced on an annual basis, any minor issues can be identified and fixed before they become larger problems.

gas safe register

This is also the opportunity for the gas-safe registered engineer to ensure that your boiler is operating safely. Did you know that every year around 60 people die from carbon monoxide poisoning?

If you need a powerful reason for getting that annual service done other than for your warranty to remain valid, then we think that’s it!

Registered with the manufacturer within 30 days of installation

It’s not unusual for there to be a requirement for the new boiler to be registered with the manufacturer within 30 days of installation. This, in turn, provides the start and end date for the boiler warranty.

A boiler engineer will often do this for you, but do check with them that it’s been done to make sure there are no problems should you need to claim on the warranty in the future.

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Boiler installed within 12 months of manufacture

Now, this shouldn’t be a problem when you’re using a professional company for the installation. They will know to check all boilers to ensure that they’re well within the manufacturing period.

However, if you’ve ever been tempted to buy from an online auction or marketplace, then beware! That bargain priced new boiler might not prove to be such a good deal when you end up without a manufacturer warranty.

Completion of the benchmark commissioning paperwork

installation complete

The benchmark form or commissioning paperwork is a checklist that the engineer completes during the installation. It shows that they have followed the manufacturer’s guidelines in fitting the boiler and connecting it to the central heating system.

The paperwork covers installation, commissioning and servicing to ensure that it’s completed in a safe and efficient way, and in accordance with the appropriate Building Regulation.

So to ensure that you get the full boiler warranty period, make sure that your boiler is fitted by an accredited engineer who completes all the paperwork and that it’s included in the boiler replacement cost when buying the boiler.

Don’t forget!

It’s not unusual for a boiler manufacturer to request a copy of the completed benchmark form if you make a claim on the new boiler warranty.

So, make sure that you put it somewhere safe to keep your warranty valid!

Using only manufacturers approved parts

If you do need a boiler repair then the warranty may require that only manufacturer-approved parts can be used.

So, while it might be tempting to go for a cheaper generic part it may mean that the manufacturer’s warranty is no longer valid.

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How can you extend a boiler warranty?

As you’ll see in the next section, manufacturers offer different ways in which you can extend both boiler warranties or a boiler guarantee.

Some boiler brands provide extended warranties when the boiler installation is carried out by a gas safe registered engineer who has also attended their in-house training.

Others will provide a long warranty when a specific filter is fitted at the same time installation is carried out.

Then there’s the opportunity to extend the manufacturer warranty through the payment of an extra cost, and finally, you could take out a coverage plan through an external company such as Homeserve.

Warranties by the boiler manufacturer

We’ve already mentioned that most manufacturers offer different warranty periods across different boiler models. So, we’ve come up with a quick summer for you for some of the most popular and best boiler companies.


Baxi 600 combi boiler

Baxi is one of the most flexible companies when it comes to their boiler warranty and that’s because they provide 60 days on either side of the installation date to get your boiler serviced.

That’s perfect for those times when life is hectic and you completely forget to get the annual Baxi boiler service arranged.

Do be aware though that Baxi may ask you to pay a deposit before an engineer comes out if your boiler breaks down. If the problem turns out not to be boiler-related and so not covered by the standard warranty, then you’ll end up forfeiting the deposit.

Get a Baxi boiler price if you are looking for this.

Baxi warranty period

Baxi offer between a three and ten-year warranty on their new boilers. The Baxi 200 boiler is at the lower end with just three years of boiler cover while the Baxi EcoBlue Advance gets an impressive 10-year warranty.

Glow Worm

Glow Worm is one of the boiler companies that have decided to offer a guarantee rather than a warranty. They do offer extended warranty cover but that’s only when new boilers are installed by a Glow Worm Club Energy Installer.

Glow Worm guarantee period

Glow Worm offer some great budget boilers but they’re not one of the most generous companies when it comes to boiler cover. Their Glow Worm energy boiler has just two years of cover and that goes up to five years for the Glow Worm Ultimate 3. To ensure this cover stays valid, you should get an annual Glow Worm boiler service.

Glow-worm boiler prices are a little higher than the rest but


Valliant boilers have the standard conditions for their warranty through the boiler must be fitted by a Vaillant Advance Installer if you want to get the extended warranty. You should also get Vaillant boiler service to ensure you warranty year after year.

Vaillant also offers a guarantee rather than a warranty but do be aware this does just apply to the boiler and not to any other Vaillant products installed at the same time.

Valliant guarantee period

The standard Vaillant guarantee term stretches from two to five years. However, this goes all the way up to a ten-year warranty/guarantee, for their entire range, when boilers are fitted by a Vaillant Advance Installer.

Worcester Bosch

For the best warranty from Worcester Bosch boilers need to be fitted by a Worcester Accredited Installer. Do be aware that Worcester Bosch will charge if called out for what turns out to be a non-boiler fault.

Worcester Bosch Greenstar 4000

This also applies if you’ve not met all the conditions such as annual boiler servicing or if you’ve not got all the paperwork available for the engineer to see. This means that you should be sure to have everything prepared and to get your Worcester Bosch boiler service done every year.

Unlike Vaillant, Worcester Bosch also provides a guarantee to other qualifying products as long as they’re fitted at the same time as your new boiler. So this might include the WAVE or Comfort controls or a Greenstar Filter.

Worcester Bosch guarantee period

The standard guarantee from Worcester is an impressive five to seven years. However, this then leaps up to a 10-year warranty/guarantee for their extended cover.

This is a company that not only has a strong reputation for some of the best heating solutions they also have some of the best boiler guarantees.

View our Worcester boiler prices page for further information.

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How long should a warranty be?

10 year boiler warranty

Different companies can offer a range of different warranty times, depending on what the customer wants and the boiler that they are selling. Typically, manufacturers will offer a minimum of 5-year warranties for their boilers, although a lot of the top companies can offer around 8-12 years.

Is boiler warranty worth it?

Depending on the terms of the warranty and the boiler manufacturer, boiler warranty can be very much worth getting, as you will be covered in the majority of problems your boiler might have. Longer warranties are also usually more expensive, but can often save you money long term as money isn’t being spent on constantly repairing your boiler, given that you get annual service.

Most of the time, should your boiler have a problem, it will be covered under your boiler warranty, saving you money on any extra repairs or parts that might be required for it.

How to keep my boiler warranty valid?

Almost all warranties have the same policy, which is to make sure your warranty stays valid, you have to get it serviced at least once every year. This is not only beneficial in the sense that your warranty stays intact, but when it gets serviced annually, you can make sure your boiler is in good condition.

Engineers will check that all the parts of your boiler are up to scratch and produce a full report on your boiler’s condition. Then if your boiler requires new parts or repairing, this will likely be covered under your boiler warranty.

Who offers the best boiler warranty?

The boiler warranty provides you with peace of mind that in the unlikely event of your boiler breaking down that you’re not going to face a big bill and have to get a new boiler replacement quote because it’s totally broken.

But, as you’ve seen there are huge differences in the length of a standard warranty and several options for extending that when you’re prepared to pay an additional cost.

boiler warranty

It’s not always easy to find all the information you need to understand exactly what a manufacturer is offering. But, that’s important information to have before purchasing a new boiler.

After all, it might seem to be the best boiler but if the manufacturer isn’t offering a decent warranty then that might raise concerns about the confidence they have in their products.

That’s why we make life so much simpler for you with our new online boiler quote service.

Simply provide a few details about what you need from your heating system and we’ll provide you with a whole range of new boiler quote options all with a fixed price including installation.

Even better, you might also find that we’re offering warranties that are even longer than going directly to the manufacturer!

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