Repair or replace your boiler?
A rule of thumb from a Gas Safe engineer, the numbers to compare, and the signs a boiler is near the end.
Smell gas?
Do not use this page. Leave the property, do not use switches, and call the National Gas Emergency Service on 0800 111 999.
The guide
When a repair makes sense
The short answer: repair a boiler that is under about ten years old when the fault is one part that is still made. Think about replacing it when it is 12 to 15 years old and breaking down more than once a year, when parts are no longer available, or when the repair would cost close to a third of a new boiler. A new combi typically costs £1,800 – £2,800 fitted, so that third is roughly £600 – £950.
Age on its own is not a verdict. A well-serviced 12-year-old boiler can have years left; a neglected six-year-old one can be on its third fault. The pattern matters more. One repair after years of reliable running is normal wear. Three call-outs in one winter is a boiler telling you something.
Parts are the hard limit. Manufacturers stop making parts for older models, and once a key part such as the heat exchanger or the main circuit board is unavailable, a repair stops being an option at any price.
Efficiency is the quiet cost. Gas boilers fitted before 2005, when condensing models became the rule, send much more heat out of the flue. Replacing one usually lowers the gas bill, though by how much depends on the house.
Ask for both numbers. Andy diagnoses before he replaces any part. If the boiler is worth fixing, you get the repair price; if it is near the end, he says so and gives you the replacement price too, so you are comparing real figures rather than guesses.
Warning signs
Signs a boiler is near the end
Any one of these is worth a look. Several together usually mean it is time.
- The pressure keeps dropping and needs topping up week after week.
- Radiators take far longer to warm up than they used to, or stay cold at the bottom.
- It locks out or shows fault codes again and again.
- Banging, gurgling or kettling noises when it fires up.
- A yellow or orange flame instead of a crisp blue one, or soot marks on the case. Switch it off and ring a Gas Safe engineer: these can be signs of poor combustion and carbon monoxide.
Questions
Common questions
Keeping the one you have? A full service is £90 – £120. What a service includes.
How long does a boiler last?
Typically 10 to 15 years, depending on the make, how hard it works and whether it has been serviced every year. An annual service is the single biggest thing that stretches a boiler's life, and most manufacturers need the service history to honour a warranty claim.
Is it worth repairing a 15-year-old boiler?
Sometimes, for a cheap, simple fault on a boiler that has otherwise been reliable. At that age, though, parts get harder to find and the next fault is rarely far behind. Get the repair price and the replacement price side by side before you decide.
Will a new boiler lower my gas bill?
Usually, if the old one is a non-condensing model. A modern condensing boiler sends far less heat up the flue. The saving depends on your house and how you use the heating, so be wary of anyone promising a fixed figure.
Get the repair price and the replacement price
Andy diagnoses the fault first, then tells you honestly which makes more sense. New combis from £1,800 fitted.