What is Rare Plumbing Website?

A bespoke digital atelier providing precision engineering and climate control services for London's most discerning luxury estates.

What is the average lifespan of a boiler?

Most modern condensing boilers last 10–15 years with regular annual servicing. Beyond 12 years, repair costs and breakdown frequency typically rise sharply.

Is it worth repairing a 10-year-old boiler?

It depends on the fault. Minor repairs (thermostat, pump) are usually worth doing. Major faults like a cracked heat exchanger on a boiler this age are rarely worth repairing — replacement is usually the better investment.

How much does a new boiler installation cost?

A combi boiler installation in London costs £3,200–£4,200 including the boiler, system flush, magnetic filter, Gas Safe certification and smart thermostat. A system boiler with a cylinder costs £4,800–£6,000. See our full pricing guide for a breakdown.

Can a new boiler reduce my energy bills?

Yes — modern A-rated condensing boilers are up to 30% more efficient than boilers over 10–15 years old, typically saving £200–£400 a year on gas bills.

Do you offer a replacement assessment?

Yes — our engineers will assess your existing boiler, give an honest repair vs. replace recommendation and provide a fixed quote with no hidden extras.

Should I replace my boiler with a combi or system boiler?

If your home has 1–2 bathrooms, a combi boiler is usually the right replacement — compact, cost-effective and instant hot water. If you have 3+ bedrooms or 2+ bathrooms, a system boiler with an unvented cylinder (Megaflo) delivers mains-pressure hot water to multiple outlets simultaneously. See our combi vs system boiler comparison for a detailed guide.

How long does a boiler replacement take?

A like-for-like combi replacement takes one day. Switching from a regular boiler to a combi, or adding a system boiler with a cylinder, takes 1–2 days depending on the property and pipework required.

What warranty do I get with a new boiler?

Premium brands like Vaillant, Viessmann and ATAG offer 5–10 year warranties when installed by an accredited engineer and serviced annually. Worcester Bosch and Ideal offer 5–7 year warranties. We register your warranty on your behalf after installation.

020 7458 4949

18°C020 7458 4949 Book Now

Boiler Repairs Plumbing Underfloor Heating Central Heating Combi Boiler Install Power Flushing Smart Thermostats Air Conditioning PPM Maintenance

Boiler Guide

Boiler Repair vs Replacement

Is your boiler worth fixing? Or is replacement the smarter investment? Expert guide with cost comparison and efficiency gains.

Consultation

Book This Service

Available 24/7. Gas Safe registered engineers.

Replace your boiler when it is over 10–12 years old, when repair costs exceed 60% of the installation cost, or when a major component like the heat exchanger fails. A new A-rated condensing boiler can reduce gas bills by up to 30% and comes with a 5–10 year warranty. RARE provides fixed-price quotes with honest repair-vs-replace recommendations.

Quick Facts

Average lifespan: 10–15 years with regular annual servicing
Replace when: Over 10–12 years old or repair exceeds 60% of replacement cost
Efficiency gain: Up to 30% lower gas bills with a new A-rated boiler
Warranty: 5–10 years on new boiler installations
Installation time: 1 day for like-for-like combi replacement
Next step: Assessment with honest repair-vs-replace recommendation

The Boiler Rule of Thumb

There's a simple formula: boiler age × repair cost ÷ installation cost. If the result is greater than 0.6, replacement is usually the better investment.

Example: A 12-year-old boiler needing a £800 repair (12 × 800 ÷ 3,500 = 2.7). Replacement is the smarter choice.

Key factors in the decision

Boiler Age

Modern boilers last 10–15 years. If yours is older than 10, replacement saves money long-term.

Repair makes sense

Under 8 years old

Consider replacement

8–12 years old

Replace now

Over 12 years

Repair Frequency

If your boiler needs repairs more than once per year, it's signalling failure. Replacement stops the cycle of expensive call-outs.

Boiler Efficiency

Old boilers (pre-2005) are 60–70% efficient. New condensing boilers are 90%+. A 20% efficiency gain saves £200–£400/year on gas bills.

Parts Availability

Obscure boilers become hard to repair. Spares cost more. Rare parts mean longer waiting times during breakdowns.

Repair vs Replace Cost Comparison

Scenario	Repair Cost	Replacement Cost	Better Choice
6-year-old boiler, thermostat failure	£350	From £3,500	Repair
10-year-old boiler, pump failure	£650	From £3,500	Repair
12-year-old boiler, heat exchanger crack	£1,200	From £3,500	Replace
15-year-old boiler, multiple faults	£2,000+	From £3,500	Replace

Why Upgrade to a New Boiler?

Save on Bills

Modern condensing boilers save £200–£400/year on gas costs.

Reliability

10–15 year lifespan with minimal repairs.

Smart Control

Integrated smart thermostats. Control heating from your phone.

Peace of Mind

Warranty coverage and predictable operating costs.

Need Expert Advice?

Our engineers assess your boiler and recommend the best option for your home and requirements.

020 7458 4949 Boiler Assessment

No-obligation advice

Honest assessment

Compare repair vs replace

Fixed pricing

Boiler replacement — complete topic guide

Combi Boiler Installation

For flats & smaller homes

System Boiler Installation

For larger homes & plant rooms

Hot Water Cylinder Installation

Megaflo, OSO & unvented cylinders

Boiler Installation Costs

Full London pricing guide

Combi vs System Boiler

Which type is right for your home?

Vaillant vs Viessmann

Brand comparison

Boiler Repairs

24/7 emergency & planned repairs

Boiler Servicing

Annual Gas Safe service

Get a Boiler Quote

Fixed price in 3 steps

Heat Loss Calculator

Size your boiler correctly

FAQ

Repair vs Replace Questions

Still have questions?

Reviewed by RARE Plumbing London Engineering Team

Gas Safe Registered Heating Engineers · Reviewed 28 August 2026