How long is piece of string? (Or how long should a domestic boiler last?)

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How long should a domestic boiler last?

And by "last", i mean, how long does it remain economically viable?

I suppose there are a few key factors.

Cost of unit,
Cost of install,
Cost of maintenance/servicing,
Cost of decommissioning.
Future tech efficiency costs
Reliability
Warranty
Parts availability.

Lots of ways to figure this out, you can graph the costs over time to give you a cut off.

If you have an old, inefficient boiler, your point of return will be shorter, but then again, efficiency is controversial as the average working condensing boiler efficiency in the UK is about 82% (apparently).

Boilers are modular? You can repair or replace parts on an ongoing basis. Does this mean a boiler kept in good condition can last as long as parts are available?

In fact, is that the limit? Parts availability?

You are not normally going to recover the install, purchase and decommissioning costs of a boiler by efficiency improvements surely?

How long are parts available? My Suprima is getting on for 20 years old and parts are readily available. Not that there is much in it to go wrong, which is great, I'll take the 4% efficiency hit and you can keep your order-of-magnitude increase in complexity.

Why does the industry say that a boiler lasts only 10-15 years?

Which bit is failing so badly that they are not economically viable after that time?
 
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You are fogetting the most important factor,who fitted it in the first place,boiler slingers and grant scheme installers are the cause for more boiler early repacement thany anything else
 
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Ours is 16 years old and outlaws is 20 and can still get parts and both going OK.
I might be wrong but the sludge and rust in system kills them off early. Ours has had new heat exchanger and some smaller parts fitted but no sludge in system.
I think a boiler should last over 20 years easy but I'm not convinced some of the locations they are fitted help especially with damp
 
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Mine has been in 25 years (Ideal FF240) and have been looking at replacing with condensing boiler at a cost of £2000. New boiler states 92% efficient, old one 74% but a bit like mpg's it all depends how things are run and set up so actual gas savings on a £1200 yearly gas bill questionable (especially now this is going to increase by 50%). It grumbles a bit but central and water heating still OK and have a standby flue fan ready if required (which seems to fail every 7 years or so due to seized bearings), only other thing ever required was a replacement gas valve. Jury still out.
 
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Older gas boilers (thinking my old Baxi) had very few components and no moving parts (apart from the gas valve) so as long as the hex wasn't bunged up and still held water they would pretty much run for ever.
Modern boilers have all manner of moving parts (fans, diverter valves) and electronics of varying sophistication. The electronics package is the big nasty- if that fails on anything more severe than a power supply or simple component (cooked resistor, failed cap or diode) then repair is likely to be prohibitively expensive, replacements could be rare and similarly pricey. Probably sensible to depreciate it over 10 or 12 years- meaning after that time be prepared to replace. The economics may change if gas boilers actually do get banned from new builds.
 
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My boiler a Stelrad Ideal seems to date back to the 80s

I guess it will go bust eventually, it gets serviced every year and fingers crossed it will last a bit longer.

it’s outlasted the heating engineer who has now retired - every year, his advice was: this old boiler is primitive but solid and simple, modern boilers go wrong. As his job was fixing boilers I guess he knew what he was talking about.
 
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Why does the industry say that a boiler lasts only 10-15 years?

Housing association I know has a 10-12 year lifecycle replacement policy. Works out about 100 boilers a week.
 
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As @Notch7 , the heat exchangers in older boilers tended to be much more substantial bits of metal and with far bigger waterways- all combined to reduce the amount of energy that went into the water per second but made them less susceptible to blockages and leaks
 
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Price of gas changes the equation a lot - I was wondering what the payoff is to replace my Band B, but it's another venerable ideal classic (and I have a brand new spare fan and PCB) - so its probably going to be never.
 
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How long should a domestic boiler last?

And by "last", i mean, how long does it remain economically viable?
Depends on the quality of the installation and ongoing maintenance throughout the boiler's lifetime (as well as the quality of the appliance being installed of course).

If you have an old, inefficient boiler, your point of return will be shorter, but then again, efficiency is controversial as the average working condensing boiler efficiency in the UK is about 82% (apparently).
Again, this is affected by the installation. It's perfectly possible to achieve manufacturers quoted 92-95% efficiency but done-in-a-day box slingers aren't interested in setting up the boiler for best efficiency. They just want to get it on the wall, switch it on, and get paid.

Boilers are modular? You can repair or replace parts on an ongoing basis. Does this mean a boiler kept in good condition can last as long as parts are available?

In fact, is that the limit? Parts availability?
It certainly can be a limit. Parts are usually available for a minimum of 15 years after manufacture, but many can be available for much longer than that.

You are not normally going to recover the install, purchase and decommissioning costs of a boiler by efficiency improvements surely?
It can be done, but the payback is certainly not immediate. Depends on the efficiency of the outgoing boiler of course. If you're changing an old dinosaur G-rated boiler for an A-rated one, the payback will be much faster than changing a B to an A. Changing one condensing boiler for another will never pay for itself in gas savings alone.

Why does the industry say that a boiler lasts only 10-15 years?

Which bit is failing so badly that they are not economically viable after that time?
The boiler replacement industry says this because they want you to believe you need a new boiler every 10 years. They have said it over and over until the general public believe it to be true, in much the same way that Worcester have spent millions of pounds telling people over and over that their boilers are the best, until people believe it to be true. Between them they've built up the perfect business model of boilers being replaced every 10 years with a brand everyone has heard of and believes to be the best, because they've been told that it is. As a result, box-slingers with no technical knowledge of what's inside the box beyond that which they need to switch it on, can sell 100+ boilers a year to a general public who believe their boiler needs replacing because it is ""old"" and who have already mentally selected their next boiler purely based on the badge on the front.

If word got out that neither case is true - that boilers will happily last for 25-30 years and there are better manufacturers out there who are also charging less money - the box-slinging boiler replacement industry falls apart and the country's biggest manufacturer suffers too. As I said above, some installers who have based their entire business model around replacing boilers can, as a one man band, be found to be replacing over 100 boilers a year each. They are responsible for boilers not achieving the efficiency on the data badge as they simply aren't allowing enough time to set the boilers and systems up correctly, and they are responsible for the myth that a new boiler will only last 10-15 years as they need that to be the case in order to have a viable business.

Personally I think the most boilers I've replaced in a year is about 12, and most of those are conversions to a different system type rather than because the existing boiler is actually broken.
 
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@muggles , super reply.

I tried looking for real world efficiency figures for condensing boilers but its tough info to find and its a tough comparison to look at real world gas usage of my old boiler vs a new one.
Hence my question because if the old girl is going to die soon anyway, it becomes a moot point.
However, its quite a simple boiler so really, it could easily plod on for another decade or so, at which point alternative methods may have become the norm. (Electric, solar, hydrogen, etc).
Or not.
 
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A condensing boiler 92% efficiency will only be achieved for a short while and under optimum conditions majority of the time it will be working at just over 80%. so dont base any calcs on the headline figure
 
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I have an old Ideal FF360 that I was going to replace, but looking at the cost, it is just not worth it, even with the increase in gas prices. If I repair it when it breaks, it will probably outlive any new boiler I could replace it with, at a much lower cost. Most of our demand is hot water, so the Ideal FF360 conservatively rated at 78% it is probably only 5% less efficient than a new one in real-life service. A new boiler will not even pay for its purchase price in gas savings before it will need to be replaced.

I have a spare fan, and a new flu, but would be interested in obtaining a complete used boiler (FF350 or 360) for parts if anyone has decommissioned one in good shape recently. I am in Norwich.

To answer the original question, I doubt any new boiler will last much more than 10 years before it becomes uneconomical to repair.
 
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