Should I repair or replace my boiler? Re February 2, 2023

Should I repair or replace my boiler?

Boiler losing pressure

The big question we all inevitably ask at some point is, do we move towards a boiler replacement or a boiler repair? 

When your boiler reaches a certain age, and it starts to have issues, the inevitable question arises – should I keep repairing it or just replace it? It can be tempting to just keep repairing it as the thought of spending a few thousand pounds on a new one is quite daunting, but those repair bills can add up and a boiler replacement will need to be considered at some point. According to a study done by the BEIS (Department for Business, Energy & Industrial Strategy), 66% of UK homeowners would only replace their current boiler if the system failed or showed strong signs of deterioration.

Searching for the right boiler for your home can be difficult, with salesmen throwing technical jargon at you that makes absolutely no sense and trying to convince you to buy things you don’t need. That’s where WarmZilla comes in – you answer a few simple questions on our website and we’ll suggest the perfect boiler for your home – you don’t need to understand what a gravity-fed system is or what kW boiler you need, our system does the work for you.

Replacing your boiler will save you money on your heating bills

So your trusty old boiler has been going for twenty-five years and hasn’t failed you yet, why would you replace it? Because at some point, it will fail, and it could leave you without heating and hot water in the meantime. Not only that but switching to a more modern energy-efficient boiler will save you money on your utility bills.

Repairing your old inefficient boiler will cost you more in the long run

If your old boiler breaks down and you opt to repair it rather than bite the bullet and get a boiler replacement, it’s much more likely to break down again, leaving you with the quandary – ‘How many times do I get it fixed before replacing it?’. 

As your boiler gets older there is also the issue of parts being discontinued as the boiler is no longer made, and the requirement for spares becomes obsolete.

Signs you need a boiler replacement

Here are some signs that you might need to start looking for a new replacement boiler:

  • Water not heating up as quickly as it used to or getting as hot as it used to
  • Banging, whistling, gurgling noises coming from your boiler
  • Leaking or dripping from the boiler
  • Pilot light going out (back boiler)
  • Poor water pressure

In addition to the operation of your boiler, there are financial benefits to replacing an older boiler model. According to the Energy Saving Trust* you could save up to £305 per year by upgrading your old boiler to an energy-efficient A-rated boiler, which typically operates at 90% and over energy efficiency, which is obviously much better for the environment too.

Answer a few questions and let us recommend the ideal boiler for your home – so get a quote now

How can I repair my boiler?

There are many common issues with boilers and heating systems that you may want to try before replacing your boiler, it may be a simple fix that will keep your boiler going for another few years. Here are some quick fixes: 

  • Is your boiler still under warranty? It may sound obvious but it’s always worth a phone call to your boiler manufacturer to see if it’s still covered – whether under parts and labour or just parts, it could still save you some money. Your boiler make and model will be on the boiler.
  • A frozen condensate pipe is a very common boiler issue and one that is easy to fix by yourself with some warm water.

  • Another one that may sound obvious but make sure the thermostat is set to the correct time, or in the case of a smart thermostat, that it’s connected to the boiler. Sometimes smart stats can drop the connection and need to be reconnected to the boiler.

  • Bleed your radiators. If your home isn’t as warm as it should be, check your radiators to see that they’re all hot and that there any cold pockets on them. If air gets into the system, you can lose heating efficiency.

  • Leaks. Check all your radiators for any leaks, any leak in the system can depressurise your boiler and cause it to stop heating. On your boiler controls, there will be a gauge telling you the current pressure of your boiler, if this drops into the red zone then you may need to repressurize the system. Your boiler will stop working if the pressure drops below a certain level.

If these fixes don’t work you can try calling out a Gas Safe registered engineer to inspect the system. You can expect to pay a minimum call-out charge of £50 in addition to any work or fitting of replacement parts.

New boiler costs

A new boiler is relatively expensive, WarmZilla boilers start from £1819, including installation, smart thermostat, ten-year guarantee, flues and fittings, and a smart filter.

This price is quite competitive, especially when you look at the flexible finance options, allowing you to pay monthly rather than one big lump sum upfront. Payments can be as little as £11.67 monthly for a brand-new Ideal Logic boiler.

Ideal Boiler Installation

New boilers on finance

Boiler finance is the most popular payment option – you can spread the cost interest-free (0% APR) over 24 months or up to 10 years (11.9% APR) if you want to get those monthly payments right down. The monthly repayments on your boiler finance plan will depend on the length of term finance you select, the boiler you choose, and the deposit amount you choose to pay.

Boiler finance deposits

Deposit amounts vary between 10-50%. The actual deposit amount you will pay will depend on the boiler model you choose to buy. Deposit amounts vary between £180 – £1100. The example above shows how the monthly deposit can make a difference in monthly repayments.

Boiler finance with a bad credit history

If you’re applying for boiler finance/credit, the finance provider will do a credit check which is standard practice.

Generally speaking, the pass rates for boilers on finance are quite high, and our selected finance providers are known for their high acceptance rates too. But in some cases, if you’ve had a recent CCJ or any IVAs within the last 5 years, it can get a bit tricky – so please contact our support team to find out more about the available finance options to you and how we could help.

Time for a boiler replacement?

The first step is to identify what kind of boiler you currently have. There are four main types of boiler:


Combi Boiler
The most popular boiler type in the UK. You can identify a combi boiler as it is not connected to a hot water storage tank (airing cupboard) or a cold water storage tank (usually found in the attic or loft). A combi boiler works by heating water directly from the mains supply, this means that you don’t waste energy by heating water which you may or may not use.

System Boiler
A system boiler has a hot water storage tank but doesn’t have a cold water storage tank. They are usually found in older houses or houses with more than one bathroom as they can supply hot water simultaneously to multiple bathrooms as it’s stored in the hot water tank.

Regular Boiler
Standard boilers have both a hot water cylinder (usually in the airing cupboard) and a cold water storage tank in the attic/loft. Like system boilers, they can cater for multiple bathrooms using hot water simultaneously but they do take up a lot of storage space with tanks. Standard boilers are sometimes referred to as traditional, standard, open vent or heat only boilers.

Back Boiler (BBU)
Back boiler units are located behind an electric gas fire. As is the case with a regular boiler they will usually have a hot water storage tank and a cold water storage tank. Back boilers are becoming less and less common as they are less efficient than modern combi boilers but they do last for a lot longer than the combi boilers.

Hopefully, you will now be able to identify which kind of boiler you have.

As well as being able to identify the type of boiler you have, hopefully, you will have some idea of what each boiler type does and which would work best for your home. We recommend combi boilers as they are so efficient, easy to install and take up less space as they don’t require storage tanks. There may be additional costs involved if you are replacing a system or regular boiler with a combi as there will be storage tanks coming out and pipework may have to be moved accordingly but you will soon make these costs back on increasing energy efficiency and your heating will perform better also.

Will any boiler service any house size?

In short, no. You will need to choose a boiler that can cope with the heating demands of your home. This depends on the size of your home, how many radiators and how many baths there are. Below is a very rough guide on the size of boiler that will cater to your home.

24 – 27 Kw Combi
Suitable for most flats, apartments and smaller houses with up to 10 radiators and 1 bathroom.

28 – 34 Kw Combi
Suitable for 3-4 bed houses with up to 15 radiators and 2 bathrooms.

35+ Kw Combi
Suitable for large houses with up to 20 radiators and 3 bathrooms.

Again, this is not something you will need to worry about when getting a boiler quote from WarmZilla as we will automatically suggest the right Kw boiler based on the answers you give to survey questions.


Your boiler is one of the hardest working, most underappreciated but vital appliances in your home. If you’re thinking about replacing it, then you want to make sure you get the right one. Do some research so you have some understanding of what would work best in your home.

If your boiler has stopped working then you may not want to wait around and do any research, you just want to get it up and running again. WarmZilla is ideal for this situation as it’s so quick and easy to purchase a boiler and get the installation date within minutes.

We hope that this guide will have provided you with some of the necessary information to help you in making a decision on whether it would be best to try and repair your old boiler or to commit to buying a new boiler. Every boiler is different and so is every person’s situation, so there isn’t one solution that will be right for everyone but it’s never been easier or more affordable to replace your old boiler. Please contact us if you have any questions. We’re always happy to help.

*The Energy Saving Trust calculates that upgrading an old G rated gas boiler with a programmer and room thermostat in a Detached house, with a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls could save you £305 per year.

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