Replacing an Old Boiler

Having your boiler replaced isn’t something you want to put yourself – or your purse – through more often than is necessary. Luckily, boilers are tough pieces of machinery and can last 15–20 years if maintained properly. That’s one reason why you should have it checked and serviced every 12 months by a professional boiler installer, and the other reason is that the warranty usually demands regular services to keep your guarantee valid.

However, if your boiler has seen better days, is no longer running efficiently, or keeps breaking down, it may be time to look at a replacement. That’s why we’ve put together this handy guide to tell you everything you need to know about home boiler replacement.

Read our full guide to gas boilers here

Why are you replacing your boiler?

Firstly, let’s look at the most common reasons for replacing your boiler and work out the best way to proceed.

Identifying if your boiler is on the blink

You’ve just run a nice hot bath, stepped in and realised it’s stone cold. That’s it — time to replace my boiler. Well, not so fast. The first thing you should do is check the digital readout, if it has one. If it’s showing an error message, it could mean your boiler has tripped. In this instance, head to our FAQ section or Google the error message. This is always worth doing, as a lack of hot water could be as simple as topping up the water pressure or resetting the system.

If you’re unsure what’s causing the issue, get in touch with a qualified boiler specialist and let them have a look. It may well need repair, so it’s best to check before paying for a central heating boiler replacement.

When a system is beyond repair

If you call an expert and they decide the repair costs would be greater than buying a new boiler, it may be time to take the plunge. Speak with the trustworthy installer, and they’ll be able to advise you on your next boiler. It’s possible that your existing boiler wasn’t the right type for your household anyway, in which case you’ll need a different one. This could provide you with a more efficient model and end up saving you money in the long term.

Upgrading an old and inefficient boiler

The older a boiler is, the less efficient it is. That comes from a combination of wear and tear plus the better technologies and regulations that keep improving boilers’ running costs. Your 30-year-old model might be steadfastly supplying you with hot water, but the chances are you’re probably paying higher bills and leaving a bigger carbon footprint.

Learn more about the benefits of high-efficiency condensing boilers

Is your boiler still right for your changing needs?

Building an extra bathroom? Is one of your elderly parents moving in? Kids flying the nest? Different household sizes and hot water demands call for different types of boilers. We’ve written a guide on what size boiler you need, so have a look at that before you make up your mind.

An important thing to note is that different boilers have different systems, and the costs will change accordingly.

Generally speaking, if you’re changing from a Combi boiler to a System boiler, or from either of those types to a Heat Only boiler, you’re going to need extra piping and tanks.

However, if you’re going the other way (conventional > System > Combi), you’ll usually be able to use most of the existing hardware, resulting in a lower-cost home boiler replacement.

Not sure which boiler you need? We have a guide on each to help you choose the best for your home:

Replacing your boiler to sell your home

There are two types of home-seekers: those looking for a cheap doer-upper, and those who want to move in, unpack their boxes and start living. Giving the second group as little to do as possible will boost your home’s value. That’s why it can easily pay for itself if you get new carpets, wallpaper... and, you guessed it, a new boiler.

By getting a new boiler, you’re making the new owner’s move less of a hassle. Also, note that if your boiler is old and has a low efficiency rating, it will definitely come up on the survey, and you could scare away buyers.

Why modern boilers are more efficient

As time has progressed, boilers have become more reliable, more efficient, smaller and easier to control thanks to technology and legislation, and that trend will no doubt continue. To encourage greener home heating, any boiler installed in the UK since 2005 has had to be a condensing boiler. But what does this mean?

Before condensing boilers, the gas flame heated the circulated water, which in turn heated the hot water and central heating you use in your home. The flame certainly did its job, but the hot gases emitted would be exhausted to the atmosphere, often at more than 200 °C, a huge waste of heat energy.

Modern condensing boilers force those hot gases through a series of baffles, where they pass around pipes containing the cool water returning from the radiators or hot water system. This has two effects: it warms the cool water, and it cools the hot gases. So by the time the “cold” water passes over the flames, it’s actually already been warmed up quite a lot.

Essentially, that means much less power from the flames is needed to raise the water to its operating temperature, resulting in a much more efficient boiler. In fact, it can work so well that the hot gases condense (turn into liquid), hence the name.