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When to Replace Your Old Boiler (And When to Have it Serviced)

Got a deteriorating old boiler and not sure if you should repair it or get a replacement?

No problem: We’ve done the research and compiled this quick guide to help you understand whether you should ditch your old boiler or fix it!

Old boiler repairs and replacement

How Long Do Boilers Last?

Some good boilers can last for decades without developing major flaws, whilst others will start breaking down in a matter of years. 

A boiler warranty tells a lot about the appliance’s projected longevity — the longer the warranty term, the more confidence the manufacturer has in their boiler.

Some boiler manufacturers offer as little as 2-years warranty, which I personally believe, isn’t a great indication of product quality.

On the flip side, a friend’s about to upgrade his boiler (it still works), and it’s 22 years old!

Like with a car, a boiler’s life span boils down to its quality and how well it’s looked after.

Note, however, that even a functioning boiler that’s several decades old may be due for a replacement. Not only are old boilers incredibly inefficient, but they may also leak harmful exhaust fumes, like Carbon Monoxide, during operation.

So, the more important question is:

How Often Do I Need to Replace a Boiler?

You should replace a boiler when the potential savings due to reduced energy consumption outweigh the monthly cost of the new boiler. To find out how much a new boiler may cost, you can use this clickable form from Heatable to get a price on screen.

Another reason to consider a replacement is when your old boiler is out of warranty and you’re faced with constant repair costs that span into the 100s of pounds.

  1. Repair Costs

Let’s start with the repair costs associated with an old boiler. Unlike energy consumption, this isn’t a savings guestimate based on studies. It’s fact, it’s the money that your boiler is costing you every year.

If you experience a major failure with your boiler within the warranty period, your manufacturer should honour that warranty and replace the offending parts.

One boiler we like is the Baxi 600 Combi. For 7 years, Baxi have got you covered. If you’re out of warranty, repairing your boiler (check out our guide to boiler repair costs here) is going to start costing you a tonne of cash.

A typical example would be a pump, which costs around £250 to replace. That said, pumps are robust, so if yours has given up the ghost, there’s a good chance other parts are about to follow suit.

Repair Costs & A Boiler Health Check

It’s unlikely you’ll find a boiler repair company offering a specific service that gives you an overview of the current state of your appliance. However, there’s no harm in asking your Gas Safe engineer next time you’re getting boiler service.

You’ll want to get them to assess expensive components for wear and damage to provide an overview of the boiler’s condition. This way, you can decide whether to get a new boiler or repair the old one.

Key components to inspect include:

  • Printed circuit board (PCB)
  • Fan
  • Air pressure switch
  • Pump
  • Heat exchanger
  • Gas Valve
  • Burner

I’d be leaning towards a replacement if your boiler:

  • Has multiple expensive components that need replacing
  • Is out of warranty
  • Has a low energy efficiency rating

Or, at the very least, I’d be getting quotes for both replacement and repair and making a decision with the facts in front of me.

Either way, you can get quotes for both repairs and replacement boilers from multiple heating engineers here.

If your looking for a replacement and specifically want a Worcester boiler, we’d suggest using Heatable. Using their clickable form, you can get a price on screen in 90 seconds with flexible finance options available.

Worcester Bosch Greenstar 4000
  1. Energy Consumption

The next thing a lot of homeowners don’t consider is energy consumption.

You may be surprised to learn how much energy some old boilers use.

The Energy Saving Trust estimates that you can gain savings of up to £840 per year by replacing an old boiler with a new one.

Given that you can get boilers on finance for as little as £25 per month, you could:

  • Install a new boiler
  • Cover the cost of repayments
  • Have £540 to spare after repayments, thanks to energy savings

Of course, these £840 savings will reduce dramatically if you’re not using a G-Rated boiler or if you live in a small property with lower energy bills.

Here’s the chart showing potential energy savings:

Old boiler rating Semi-detached Detached Detached bungalow Mid terrace house Mid floor flat
G ( < 70%) £540 £840 £445 £420 £230
F (70–74%) £380 £590 £310 £290 £160
E (74–78%) £335 £460 £275 £260 £140
D (78–82%) £305 £375 £250 £235 £125

How Much Should a New Boiler Cost?

Expect to pay upwards of £2,000. We’ve created a detailed guide to new boiler costs here.

Note that the final replacement boiler costs will depend on a variety of factors, such as:

  • Your chosen new boiler model — obviously, you can save by opting for cheaper models from lesser-known brands.
  • Boiler size and type — higher capacity boilers tend to cost more.
  • New boiler location — reconfiguring the pipework and rewiring the power supply will add to the costs.

If you’d prefer, you can jump online now and compare quotes from 3 different installers.

Then, compare the quotes directly to an on-screen price from Heatable. They’re the a new kid on the block for online boiler installation, and their prices for Worcester boilers are about as good as you’ll get.

Heatable boiler installations

You can also explore your boiler replacement options with a large national company, like British Gas. Although these companies tend to be more expensive, they often have promotions for new customers.

Also, if you’ve got an old boiler, be sure to check out the government’s Boiler Upgrade Scheme (previously the Boiler Scrappage Scheme). You may qualify for a grant to help you out with replacement costs.

Protecting Your New Boiler

As we’ve already mentioned, the lifespan of your boiler is dependent on the care you give it. If these preventative measures haven’t been put in place in your current heating system, there’s a good chance your boiler is suffering.

Annual Service (To Comply With the Manufacturer’s Warranty)

Prevention is better than repairs, and annual service from a Gas Safe engineer is going to help spot potential problems before they require expensive repairs.

And, if you want to comply with the warranty terms and conditions from most boiler brands, you’ll need to get annual service anyway. The best boiler cover plans include free annual boiler service and help you out with emergency repairs if your boiler breaks down.

There’s a quick guide to boiler servicing costs here.

Central Heating Inhibitor

Over time, the water in your heating system gets dirty. This debris is a mixture of minerals in water and bits of rust from the inside of towel rails, radiators, and the copper pipework.

Dosing your heating system will break down these particles, thus preparing them for removal from the system.

We’ve created a guide to central heating inhibitors here.

Magnetic System Filters

With the debris particles are broken down into manageable chunks, they can be caught by a magnetic system filter. We’ve created a guide to exactly what they do, and which brands are the best, here.

Most boiler installers will fit a magnetic boiler filter as standard.

And, if you know you’re in a hard water area, consider a limescale reducing filter. This device removes limescale from the heating system.

FAQs About Old Boiler Repairs and Replacement

Below, we’ll answer a few common queries about boiler repairs and replacement.

Should a 40-year old boiler be replaced?

Yes — if your boiler is 40 years old, you should consider investing in a replacement boiler and sending your old one to the scrap yard. Even if your 40-year-old boiler is still chugging along without major faults or extensive repairs, it’s still far less efficient than modern condensing boilers. This means you’re paying more on your gas bills than you should be.

Can a boiler last 30 years?

Most boilers last about 15 years before the repair bills start to mount and a replacement becomes the better option. However, in theory, yes — a gas boiler can last 30 years and more.

But even if your old boiler is still working smoothly despite its old age, you should consider its energy efficiency and its effect on your heating bills. Older boilers — especially those that have been in service for several decades — are likely only 60% efficient; this means that you only get 60p worth of heat for every pound spent on gas.

In contrast, new condensing boilers are typically over 90% efficient, so you can see some significant savings on your bills by getting a modern replacement boiler.

How efficient is a 60 year old boiler?

A 60 year old boiler is likely only 60% efficient, meaning that almost half of what you spend on your gas bill gets wasted due to the boiler’s inefficiency.

If you’ve got a boiler that’s 60 years old, it’s time to put the old workhorse out to pasture and see which of the modern, condensing boilers would make a good replacement.

And while you’re at it, you should also consider upgrading your heating controls, as these can help you save even more on your energy bills.

What are the 3 types of boilers?

The 3 most common boiler types are combination boilers, regular boilers, and system boilers.

Combination boilers (better known as combi boilers) supply hot water on demand, getting their supply from the mains. They work without any water storage facilities, and are typically suitable for small-to-medium properties with average water demand.

System boilers heat water that gets stored in a hot water cylinder. From there, the water flows to your taps and showers as required. System boilers are a better fit than combis for households with high hot water demand.

Regular boilers work similar to system boilers, but also require feeder tanks to store water. They’re best suited for properties that already have a conventional central heating setup.

What’s Next?

Thanks for reading our guide to old boiler repairs and replacement.

Is there anything we’ve missed? Do you have any questions about boiler replacement?

Drop us a line, and we’ll get back to you as soon as possible.



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