When to replace your boiler

Key Takeaways

• • Boilers usually last 10-15 years.

  • Frequent repairs, leaks, rising bills, or strange noises may mean it’s time to replace yours.

  • Repairs can sometimes work, but older boilers often cost more to maintain than replace.

  • A new boiler is more efficient, reliable, and could save you money in the long run.

  • Always use a Gas Safe registered engineer for servicing or replacement.

Nobody wants to wake up to a cold shower or a freezing home. Your boiler should give you comfort, not stress. Let’s walk through the signs that mean it may be time for a boiler replacement, and what you can do about it.

When to replace a boiler

• • Most modern boilers last 10-15 years.

  • Regular servicing helps extend that lifespan.

  • If your boiler is around 15 years old, it’s probably time to start planning for a replacement.

Annual servicing by a Gas Safe registered engineer can help to spot problems early before they develop into more serious faults. 

Should you repair or replace your boiler?

Sometimes a simple boiler repair is enough. If your boiler is new, parts are easier to source and repairs usually make sense.

But with older boilers:

• • Parts may be discontinued.

  • Breakdowns can happen more often.

  • Repairs can add up quickly.
    
    

That’s when replacing your boiler is the smarter and more cost-effective choice.

Signs you might need a new boiler

1. Leaks or drips

• • A leaking boiler can sometimes be an emergency. 

  • Boiler leaks can come from broken parts, damaged seals, or corroded pipes.

  • Left unchecked a leaky boiler could result in far more serious problems. Water seeping into the system’s wiring can lead to electrical short circuits, or if the leak is large, it could even cause structural damage to your home.

  • Always get a leaking boiler checked out by a Gas Safe registered engineer.
    
    

2. Repeated low pressure

• • Low boiler pressure could be caused by a number of things, including a leaking boiler, bleeding radiators, leaking pressure valve, or faulty expansion valves. 

  • The ideal boiler pressure should show 1-2 on the pressure gauge.

  • If your pressure gauge shows below 1, you may have leaks or a faulty part.

  • The cost to repair can be between £80 if it’s only the pressure release valve (PRV) that needs to be replaced to  £600+ if the entire heat exchanger is broken.

  • Quick fixes exist, but repeated pressure issues suggest a deeper problem with your boiler.

  • Contact a Gas Safe registered engineer to diagnose the problem.
    
    

3. Strange noises

• • A boiler making noise can be from the pipes expanding and contracting, water moving through the system and the boiler itself firing up.

  • Noisy boilers can also occur from blockage or build-up of sludge, but this can be fixed by a power flush.

  • New, excessively loud or persistent boiler sounds could mean there’s a problem.

  • If your boiler is making a kettling, banging, gurgling or clunking sound, especially if it’s accompanied by vibrations, this can be a sign of a more serious problem.

  • Contact a Gas Safe registered engineer to diagnose the problem.
    
    

4. Odd smells

• • A Sulphur/eggy smell could be a gas leak which is very dangerous. Turn the boiler off and call 0800 111 999 (National Gas Emergency line).

  • Carbon monoxide has no smell and can be fatal if leaking from your boiler. Carbon monoxide warning signs include:

    • Yellow boiler flame instead of blue

    • Soot marks around the boiler

    • Pilot light keeps going out

    • Headaches, dizziness, nausea at home

  • If you suspect a carbon monoxide leak in your home, turn your boiler off and call 0800 111 999. 

  • It’s recommended to have a carbon monoxide alarm in your home. 

  • Boilers can produce a burning smell if an internal component is melting or burning. It’s possible that this can be repaired by replacing the particular part that’s broken, but not always. If left unfixed, this could lead to the complete failure of your home’s central heating system, so it’s important to get it investigated by a registered Gas Safe engineer.
    
    

5. Hard-to-find parts

• • If your boiler’s parts aren’t made anymore, replacement is the only option.

  • Even if parts exist, high costs may make a new boiler the better choice for longevity. 

  • During a boiler repair or service, a Gas Safe registered engineer will advise you on the best course of action. 

6. Higher energy bills

• • Boilers over 10 years old, may have as low an energy efficiency rating as a G, which means they may waste energy. 

  • New A-rated boilers use over 90% of their fuel efficiency. 

  • If you’ve noticed your energy bills creeping up without any changes to your needs or home, it may be time to get a new boiler.
    
    

7. Not enough hot water

• • If your family has grown or you’ve extended and added a new bathroom, the demand on your boiler has likely increased and you may need a larger boiler. 

  • Large homes often need a system boiler or standard boiler.

  • Smaller homes usually benefit from a combi boiler.

  • Find out which new boiler is most suitable for your home with BOXT’s boiler recommender.
    
    

8. Frequent breakdowns

• • A one-off issue is usually fine to fix.

  • But recurring boiler breakdowns can be a sign that that your boiler needs replacing. 

  • It’s often not cost-effective to keep paying for boiler repairs.

  • If you’re calling an engineer more than once a year, replacement is usually smarter.

  • BOXT offers monthly boiler finance plans, and a boiler plan which includes servicing and repairs as part of the monthly cost.
    
    

What to consider before buying a new boiler

To help make the process of choosing a replacement boiler a little easier, we’ve compiled a list of the things you should consider to ensure you’re making a worthwhile investment.

1. Price

It’s generally recommended to invest in the best boiler you can, as they’ll usually come with longer warranties to ensure your boiler lasts as long as possible.

2. Brand Reliability

Some brands are more dependable and have longer warranties than others. BOXT only stocks trusted brands with strong guarantees, ranging from 5-12 years.

3. Your Engineer

Only use a Gas Safe registered engineer. It is illegal for anyone to install a boiler if they’re not Gas Safe registered. 

BOXT engineers are Gas Safe registered and have a minimum of two years of experience. BOXT installers have all passed our rigorous 25-point vetting process, which includes a DBS check.

4. The Future

Think ahead. Will your family grow? Will your home change? Choose a boiler that’ll meet your needs for the next 10-15 years.

Need a New Boiler?

We’re here to make it simple. At BOXT, you’ll find:

• • A-rated, energy-efficient boilers.

  • Flexible payment options.

  • Expert engineers who handle everything for you.
    
    

Whether you want to pay upfront, spread the cost, or join BOXT Life for monthly servicing and peace of mind—we’ll help you find the perfect fit.