New Boiler vs Boiler Repair

When your boiler starts having problems, the question comes down to money: is it cheaper to repair it, or replace it?

The answer depends on four factors. Read on to find out about each so that you can make the right call.

Should you repair or replace your boiler?

The answer usually comes down to age.

If your boiler is under 10 years old, within warranty, and this is a first breakdown with a single fault, repairing it is likely the right call.

Meanwhile, once a pre-2005 boiler starts breaking down, it rarely makes financial sense to keep repairing it.

These are non-condensing models, which are significantly less efficient than modern alternatives.

Replacement is an especially good choice when:

• You’ve had two or more breakdowns in the past 12 months
• A single repair is going to cost £500 or more
• Your engineer is struggling to source the parts (manufacturers typically stop producing spares after 10 years)
• Your gas bills have been rising steadily without any change in how you use your heating
• The boiler keeps locking out and needing a manual reset to restart.

How to know if your boiler needs replacing

Beyond the signals above, look out for these warning signs that a boiler is nearing the end of its operational lifespan:

• Frequent lockouts: The boiler repeatedly turns off and displays fault codes, requiring manual resets.
• Noisy operation: Kettling (banging or rumbling sounds caused by limescale on the heat exchanger) or grinding pump bearings indicate severe internal wear.
• Persistent pressure drops: The system constantly loses pressure despite topping up via the filling loop, indicating internal leaks or a failed expansion vessel.
• Yellow burner flame: Gas flames should burn crisp blue. A yellow or orange flame indicates incomplete combustion and potential carbon monoxide leaks, requiring an immediate Gas Safe check.
• Slow heating performance: Radiators take significantly longer to warm up than they used to, even after bleeding air.

Repair vs replacement costs

What repairs typically cost

A Gas Safe engineer will charge £80–£120 for a callout, plus £50–£100 per hour for labour (which may be higher on evenings and weekends).

Some common repair costs to add on top of this callout charge:

• Thermocouple replacement: £100–£150
• Pump replacement: £150–£300
• PCB (circuit board) replacement: £300–£500
• Heat exchanger replacement: £400–£700

A single repair can seem manageable in isolation. But an ageing boiler that breaks once tends to break again.

Two or three repairs a year at £200–£400 each adds up to £600–£1,200 annually.

And even after this, the boiler is still inefficient and more likely to break down again than a new boiler.

What a new boiler costs

• Boiler unit: £600–£2,500 depending on type and brand
• Like-for-like installation (a straightforward combi swap): £1,000–£2,000
• Conversion (e.g. switching from a conventional to a combi boiler): £1,500–£3,000+
• Total typical range: £1,500–£4,500

For more on what drives installation costs, see our guide to what to consider when replacing your boiler.

A useful rule of thumb: if a single repair is going to cost more than half the price of a new boiler, replacement is almost always the better financial decision.

How much a new boiler can save on energy bills

Modern A-rated condensing boilers achieve 90% efficiency or higher.

Pre-2005 non-condensing boilers typically manage 70–80%. That gap shows up in your gas bill every month.

Below is a breakdown of projected annual savings from replacing lower-rated boilers with a modern A-rated model, based on Energy Saving Trust data:

Property Type	Grade G Boiler (under 70% efficient)	Grade F Boiler (70-74% efficient)	Grade E Boiler (74-78% efficient)	Grade D Boiler (78-82% efficient)
Detached Property	£540	£380	£300	£245
Semi-Detached Property	£355	£250	£225	£200
Detached Bungalow	£320	£225	£200	£180
Mid-Floor Apartment	£135	£95	£80	£75
Mid-Terrace House	£295	£205	£185	£165

Figures based on Energy Saving Trust data, October 2023 fuel prices. Current savings may differ.

On a typical semi-detached property replacing a G-rated boiler, that’s £355 saved per year on gas bills alone.

Over 10 years, that’s £3,550 in energy savings. And this is before accounting for the repair costs you’ve avoided.

Is it cheaper to repair or replace in the long run?

Here’s a worked example for a common scenario: an 18-year-old non-condensing boiler needing a £400 pump repair.

	Keep & repair	Replace with new A-rated boiler
Upfront cost	£400	£2,500
Annual energy saving vs new boiler	£0	£355
Estimated further repairs over 5 years	£1,200	£0
3-year total	£1,200	£1,435
5-year total	£2,000	£725
7-year total	£2,800	£15

The repair option looks cheaper in year one. By year five, the new boiler has more than paid for itself through avoided repairs and lower energy bills.

On larger properties, where energy savings are higher, the break-even point comes sooner.

What if I can’t afford a new boiler right now?

Upfront cost is the most common reason people keep repairing a boiler that would be cheaper to replace. A few options worth knowing about:

Financing

Most boiler installers offer payment plans, including 0% finance deals that spread the cost over 12–60 months.

Monthly repayments on a £2,500 boiler over five years are often lower than the combined monthly cost of ongoing repairs and higher energy bills.

Boiler cover

For boilers under 10–12 years old, a boiler cover plan converts an unpredictable large repair bill into a fixed monthly payment.

It’s less suited to very old boilers because cover becomes harder to obtain and the case for replacement becomes stronger.

So, it can provide useful protection for a mid-life boiler in reasonable condition.

Government schemes

Households on certain qualifying benefits may be eligible for a free or subsidised boiler replacement through schemes such as ECO4. Check eligibility at GOV.UK.

Get your boiler covered with Hometree

Our boiler cover includes unlimited repairs, an annual boiler service, zero parts & labour charges, and 24/7 claims support to keep your home warm. Subject to exclusions and T&Cs apply.

With no hidden fees and coverage across England, Scotland, and Wales, we’ve got you covered.

You can get covered today or contact us for a free quote.