Figures on this page are indicative ranges based on 2026 Belfast installer pricing. Every installer quotes independently and the exact cost depends on your property and the boiler you choose.
Seven signals your boiler is near end of life
- 01 Boiler is 12+ years old and has had a repair in the last 18 months.
- 02 Repair costs are running above £400 on a single call-out.
- 03 Gas or oil bills have crept up year on year despite similar usage.
- 04 Boiler is noisy, kettling, banging, hissing on warm-up.
- 05 You need more hot water capacity (new bathroom, bigger family).
- 06 Manufacturer has stopped making parts (common on 20+ year old boilers).
- 07 The pilot light or ignition is failing more than once a month.
The 50% rule
Rough heuristic: if a single repair is going to cost more than 50% of the price of a new boiler, replacement usually makes more sense. A £400 PCB swap on a 15-year-old boiler rarely stacks up when a new flagship combi with a 10-year warranty sits in the £2,200–£2,800 fitted range.
Efficiency compounding
Boilers lose 10–15% efficiency over their lifetime. A 15-year-old non-condensing boiler runs at around 75% efficiency; a new A-rated condensing boiler runs at 94%. That's £200–£300 a year on a typical household gas bill. Over 10 years the gap covers a new boiler on its own.
Parts availability
For boilers older than 15 years, specific parts sometimes aren't available. Installers regularly report call-outs where the fix existed in principle but the part had been discontinued. If a boiler is on the edge, a proactive replacement is cheaper than an emergency one in February.
What to replace with
For most Belfast homes, a combi boiler in the Ideal Logic Max or Worcester Greenstar range is the right call — typically £2,200–£2,800 fitted, 10-year warranty, compact and efficient. Larger homes with multiple bathrooms benefit from a system boiler with an unvented cylinder, which typically pushes the total closer to £3,500–£4,500.
See the brand comparisons for an honest take on Worcester, Vaillant, Ideal and Warmflow.
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