Boiler Repair vs Replacement: When to Replace

Quick Answer: Consider replacement if: boiler is 15+ years old, repair costs exceed £500, you've had 3+ repairs in a year, or parts are unavailable. New boilers cost £1,800-£3,500 but save £150-£300 annually on energy.

The 50% Rule

If a single repair costs more than 50% of a new boiler, replace instead.

Scenario	Repair Cost	New Boiler	Decision
Old boiler, heat exchanger	£500+	£2,200	Replace
5-year-old, pump failure	£300	£2,200	Repair
12-year-old, PCB board	£400	£2,200	Consider either

Age Considerations

Age	Typical Condition	Recommendation
0-5 years	Warranty likely covers	Repair
5-10 years	Should still be reliable	Repair unless major
10-15 years	Efficiency declining	Case by case
15+ years	Parts scarce, inefficient	Seriously consider replacing

Signs You Should Replace

Definitely Replace

• No parts available
• Repeated breakdowns (3+ per year)
• G-rated efficiency (wastes 30% of gas)
• Unsafe operation (yellow flame, CO concerns)
• Major component failure on old boiler

Probably Repair

• Under warranty
• First breakdown in years
• Minor fault (thermostat, valve)
• Boiler under 10 years old

Financial Calculation

Old G-rated boiler (55% efficient): Annual gas cost: £1,200

New A-rated boiler (92% efficient): Annual gas cost: £850

Annual saving: £350 Payback period: 5-8 years

What a New Boiler Gives You

• Efficiency: 90%+ vs 60-70% on old models
• Reliability: Fewer breakdowns
• Warranty: 5-12 years coverage
• Smart controls: Better temperature management
• Lower bills: Typically £150-£300/year saved

Glasgow Boiler Prices 2025

Boiler Type	Installed Cost
Combi (budget)	£1,800-£2,500
Combi (mid-range)	£2,500-£3,200
System boiler	£2,200-£3,500
Premium brands	£3,000-£4,000

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