Should I repair or replace my boiler?
Repair your boiler if it’s under about 10 to 15 years old, parts are still available and this is a one-off fault that costs well under the price of a new one. Replace it if it keeps breaking down, parts are obsolete, or it’s an old non-condensing model burning more gas than it should. Plenty of boilers I see only need a repair, so don’t let anyone rush you into a new one.
Below is how I weigh it up when I’m stood in front of a customer’s boiler.
How old is your boiler?
Age is where most people start, and it’s a fair starting point. A decent boiler that’s been serviced every year will often run 10 to 15 years, and some go well past that. Age on its own doesn’t tell you much, though. I’ve seen 18-year-old boilers still running fine and 7-year-old ones that have had three new parts.
What age does change is the odds. Past the 10-year mark, wear builds up on pumps, fans, valves and seals. Fix one of those and the next one can go a few months later. So an older boiler isn’t a reason to replace, but it’s a reason to look harder at the other points below.
If you don’t know how old yours is, check the data badge (usually inside the front panel or underneath), the paperwork from when it was fitted, or ask your engineer at the next service.
Can you still get parts for it?
This one often settles it. Manufacturers stop making parts for older models eventually, and once the stock runs out, a repair can mean waiting weeks for a reconditioned part or finding there isn’t one at all.
If an engineer tells you a part is obsolete, ask whether a compatible alternative exists. Sometimes it does. If it doesn’t, you’re into replacement whether you like it or not, and it’s better to plan that in September than find out in January.
How often has it broken down?
One breakdown in five years is bad luck. Three in one winter is a pattern.
Repeat faults usually mean more than one component is near the end of its life. Each repair on its own might look reasonable, but add them up over a couple of years and you can end up paying a good part of the cost of a new boiler while still owning an old one. Keep your repair invoices. They make this decision much easier.
What does the repair cost against a new boiler?
This is where most decisions actually get made. The table below uses illustrative price ranges only. They’re rough figures to show the comparison, not a quote. Real prices depend on the fault, the part, the boiler and your home.
| Situation | Illustrative cost | What I’d usually suggest |
|---|---|---|
| Minor fault (repressurising, a sensor, a thermocouple on an older system) | Roughly £100 to £250 | Repair |
| Major part (fan, pump, diverter valve, circuit board) | Roughly £200 to £500 | Repair if the boiler is otherwise sound |
| Heat exchanger or several parts at once | Roughly £400 to £900 or more | Usually replace on an older boiler |
| Like-for-like combi replacement | Roughly £2,000 to £3,500 | Replace if the points above stack up |
A rule of thumb I use: if the repair is heading towards a third of the cost of a new boiler and the boiler is past 10 years old, it’s time to at least get a replacement price. For a fuller breakdown of what goes into a new boiler price, read our guide on how much a new boiler costs.
Is your old boiler wasting gas?
Condensing boilers have been required for most new gas boiler installations in England and Wales since 2005. If your boiler is older than that, there’s a fair chance it’s a non-condensing model. A clue is a thin metal flue rather than a plastic one, and no condensate pipe running to a drain.
Non-condensing boilers lose more heat up the flue. A modern condensing boiler recovers much of that heat, so it uses less gas to warm the same home. Swap an old non-condensing boiler for a new one and you should see a real drop in gas use. Replace a 10-year-old condensing boiler with a newer condensing boiler and the saving is much smaller. Don’t replace a working modern boiler just to save on bills. The numbers rarely add up.
Is it still under warranty?
Check this before you pay for anything. Many newer boilers come with a manufacturer’s warranty, but it usually depends on the boiler being registered and serviced every year by a Gas Safe engineer. If yours is covered, the manufacturer may send their own engineer or cover the part.
If it’s out of warranty, that doesn’t mean replace. It just means you’re paying for repairs yourself, so the cost comparison above matters more. A new boiler comes with a fresh warranty, which is worth factoring in when an old one is starting to cost you every year.
When is a repair the right call?
More often than you might think. If your boiler is a condensing model, parts are available, it’s been reliable until now and the fault is a single component, repair it. You’ll save a lot of money and probably get several more good years out of it.
I’d rather fix a sound boiler and have you ring me again in five years than sell you one you didn’t need. What keeps an older boiler going longest is a proper annual service, which catches worn parts before they fail. Our guide on how often a boiler should be serviced explains what that involves.
What should you do next?
If your boiler has stopped or is showing a fault code, don’t take the casing off. Check the pressure gauge and your thermostat, and in freezing weather check whether the condensate pipe outside has frozen. Beyond that, it’s a job for a Gas Safe registered engineer. If you smell gas, turn off the supply at the meter if you can do so safely and call the National Gas Emergency number on 0800 111 999.
If you’re in Swindon or out towards Wroughton, Highworth or Royal Wootton Bassett, we can come and look at it. We’ll tell you straight whether it’s worth a boiler repair or whether a replacement makes more sense, and give you prices for both so you can decide.
Frequently asked questions
How old is too old for a boiler?
There's no fixed cut-off. Once a boiler passes 10 to 15 years it's worth asking whether parts are still made for it and how often it's failing. A well-serviced older boiler can keep going for years, so age on its own isn't a reason to replace.
Is it worth repairing a boiler that's out of warranty?
Often, yes. A single fault on an otherwise reliable boiler is usually cheaper to fix than replacing the whole thing. It gets harder to justify when the repair costs a big share of a new boiler, or when it's the third call-out this winter.
Will a new boiler save me money on my gas bill?
If you're replacing an old non-condensing boiler, it should use noticeably less gas for the same heat. Swapping one modern condensing boiler for another saves far less. How much you save depends on your home, your controls and how you use the heating.
Can I fix a boiler fault myself?
You can check simple things like the pressure gauge, the thermostat settings and whether the condensate pipe has frozen in cold weather. Anything inside the boiler casing or on the gas side must be done by a Gas Safe registered engineer. It isn't a DIY job and getting it wrong can be dangerous.
Do you cover my village for repairs?
We cover Swindon and the villages around it, including Wroughton, Highworth, Royal Wootton Bassett, Purton and Chiseldon. Get in touch with your postcode and a description of the fault and we'll tell you how soon we can get out to you.
