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How long do boilers last?

A father is cooking in a kitchen with two children, the Vaillant ecoTEC plus is in the background

What you'll learn

  • How long does a combi boiler last?
  • How to increase boiler life expectancy
  • Can you fix your own boiler?

If you’ve recently bought a new boiler or you’re considering when it’s time to get a replacement, you will most likely be wondering how long a typical boiler lasts.

For an average household, boilers can last up to 15 years or more depending on regular maintenance and servicing. Though it’s important to understand this timespan is conditional. Your boiler’s life expectancy may be cut short if it doesn’t receive regular maintenance, meaning you need to be proactive in looking after your boiler to prolong its lifespan as much as possible.

Whether you have a combi, system or open vent, read on to find out our expert advice on prolonging the life of your boiler.

Couple in kitchen talking to Vaillant engineer with Vaillant ecoTEC plus in background

How long does a combi boiler last?

Modern combi boilers should last up to 15 years with their high efficiency and fewer pressure issues when compared to a conventional boiler. Of course, this all depends on the quality of your chosen model and how well you look after the system.

When choosing a boiler, make sure to carefully consider the model, make and quality of the system. Although you may need to pay a little more for a higher quality boiler, you’ll find the benefits later down the line when avoiding unnecessary, costly repairs.

How to increase boiler life expectancy

There are no two ways about it, at some point you will need to replace your boiler. However, there are several things you can do to increase your boiler life expectancy and keep your central heating system running smoothly for as long as possible.

Get an annual service

We can’t stress enough the importance of an annual service from a Gas Safe Registered (GSR) engineer. A qualified professional will be able to check your boiler is running efficiently and spot early signs of damage to avoid costly repairs.

Even if you believe your boiler is running smoothly, an annual service is a sure way to increase its life expectancy by keeping it that way. For Vaillant installed boilers, an annual service is necessary to maintain your guarantee after the first year.

Prevent corrosion

As with many systems, boilers are not insusceptible to the effects of rust and corrosion over time. This then carries the potential for damage to the boiler. The best way to prevent this would be to request that your Vaillant engineer adds an inhibitor to your system. This is a protective coating that will form around the metals, preventing limescale build up and corrosion.

Please be aware, however, that an inhibitor is not a solution to limescale build up, but a preventative measure. If your system is suffering with corrosion, sludge and limescale, you’ll need your engineer to perform a powerflush (detailed below).

Prevent sludge build up

Sludge and debris can build up within the pipes of the central heating system over time, causing damage to your boiler. By installing a magnetic filter, a small component which sits within the pipework of the system, sludge will be safely filtered before it reaches the boiler.

A GSR engineer can install and clean a magnetic filter during your annual service, which will ultimately prolong the lifespan of your boiler.


If you have an older boiler, you may already be facing limescale build up or excessive sludge. This can cause blockages and corrosion to the central heating system, leading to a boiler breakdown. Quite simply, sludge build up can drastically reduce the lifespan of your boiler.

A Vaillant installer can resolve the issue with a power flush which involves pushing a specialist cleaning chemical through the heating system at high-pressure. This can take anywhere from 8 hours to 2 days, but it is necessary if you want to get the longest life possible span out of your boiler.

Can you fix your own boiler?

If your boiler is experiencing any of these issues, contact your local GSR engineer. Never attempt to fix these problems for yourself (outside of the minor fixes stated below) can void your warrantee and pose a serious safety hazard.

  1. 1

    Reset the boiler

    Firstly, try resetting the boiler using the reset function (for modern boilers) or by relighting the pilot light (for older models). It is also worth checking the timer to see if this needs resetting, which may be an easy solution to your boiler not turning on when you expect it to.

  2. 2

    Defrost frozen pipes

    In the colder months, it is possible for the condensate pipe to freeze which may prevent your boiler from starting, leading to a lack of both heating and hot water. The first thing to do in order to resolve this would be to locating the condensate pipe (which will be on the outside of your property) and begin to thaw it out with warm (not boiling) water. Once the pipe has thawed, resetting the boiler should then resolve the issue. You can find a more detailed explanation of this process here.

  3. 3

    Check for low pressure

    Check the pressure gauge on your boiler to see if the pressure has dropped too low due to natural loss or a water leak. If you find the pressure has dropped below the required pressure for it to operate, you can attempt to repressurise the system yourself.

    Do this by first locating the system filling loop. As different devices operate in different ways, you’ll need to follow your specific model instructions to repressurise the system. Read more about what to do if your boiler has no pressure, or contact a GSR engineer if you believe the problem is part of a wider boiler fault.


  • Boilers typically last 15 years with the correct care and maintenance
  • An annual service is crucial to prolong the lifespan of your boiler and maintain warranty
  • Magnetic filters and inhibitors can be used to prevent damage
  • Always consult a GSR engineer to resolve any boiler issues

Maintain your boiler's efficiency with annual servicing