Boiler warranties explained: standard, extended and the small print

Warranty vs guarantee

Manufacturers use the words loosely. A guarantee (Worcester Bosch's term) is generally a promise to repair; a warranty may carry more exclusions. In practice, what matters is not the word but the duration and the conditions attached to it.

Standard vs extended cover

Almost every boiler has two numbers: the standard term (what you get by default — as low as 1 or 2 years on some ranges) and the extended term (what you get when the conditions are met — up to 12 years on the best ranges). The gap between them is the most ignored figure in boiler buying.

• Registration — usually within 30 days of installation, sometimes by the installer
• System filter — many extended terms require a magnetic filter fitted at installation
• Annual servicing — every year, by a qualified engineer, with records kept

How 10-year warranties really work

A 10-year warranty is the manufacturer betting the boiler will not fail if it is installed properly and serviced. That is why the conditions exist — and why a 10-year boiler fitted badly is a 2-year boiler in disguise. The warranty term is the best single quality signal when comparing models.

How we show it

Every boiler in our shop shows its standard and conditional extended warranty on the card and the product page, and you can filter the whole range by warranty length. Where a model's exact terms are unconfirmed, we say so rather than guessing.