The question of whether to repair or replace a boiler is one where bad advice is common — partly because there's money to be made either way. Here's an honest take.
Signs a new boiler is probably the right call
It's over 15 years old and breaking down regularly
Boilers have a typical lifespan of 10–15 years. Beyond that, parts become harder to source, efficiency drops significantly, and you end up spending on repairs that keep it limping along rather than running well.
If you're having it repaired more than once a year, add up what those repairs cost over two to three years. Often it approaches or exceeds the cost of a new boiler — without the efficiency gains.
The repair cost is more than half the price of a new boiler
A general rule: if a repair costs more than 50% of what a comparable new boiler would cost installed, replacement makes financial sense. You're spending significant money to extend the life of an inefficient system.
It's an old G-rated boiler
Older boilers run at around 70-80% efficiency. Modern condensing boilers run at 90%+. The difference in gas bills over a year can be substantial, particularly in a larger home.
Parts are no longer available
For boilers over 15 years old, specific parts — heat exchangers, PCBs, diverter valves — can become unavailable or only sourced second-hand. An engineer will tell you if this is the case.
Signs you probably don't need a new boiler
It's under 10 years old
A boiler under 10 years old is very unlikely to need replacing. Most faults at this age are component failures — a pump, a valve, a sensor — that cost a fraction of a new installation. Don't let anyone talk you into a full replacement on a relatively young boiler without a clear explanation of why the repair isn't viable.
It's losing pressure
Pressure loss is one of the most misdiagnosed boiler problems. It's usually a small leak, a bled radiator, or a failing filling loop — not a boiler on its way out. This is a repair, not a replacement.
It's making a noise
Kettling, gurgling, and banging are usually caused by limescale, trapped air, or sludge. A power flush or a specific component replacement fixes most of these. Noise alone is not a reason to replace a boiler.
One engineer told you to replace it
Get a second opinion before committing to a boiler replacement, especially if the first engineer didn't show you specifically what's failed and why it can't be repaired. It's a significant spend and you're entitled to understand the reasoning.
What a new boiler actually costs
A new combi boiler supplied and installed in a standard configuration typically costs between £1,800 and £3,000 depending on the brand, output, and any additional work required (new pipework, flue relocation, etc.).
That's the realistic range. Below £1,500 is usually a budget brand with limited warranty cover. Above £3,500 should come with a clear explanation of what's driving the cost.
If your boiler is giving you problems and you're in Hemel Hempstead, Ealing, or NW London — get in touch. We'll tell you honestly whether it's worth repairing and what it'll cost either way.