Vaillant boilers.

What Vaillant are good at

Genuinely quiet, which is why they turn up so often in flats and in houses where the boiler is on a bedroom wall. Build quality is excellent.

What to watch

At the higher end on price, and the longest warranties need an accredited installer.

Who they suit

Anywhere noise matters, and anyone happy to pay a bit more for it.

What a Vaillant actually costs

£2,400 to £3,300 fitted for a like-for-like combi swap in an average home, including the appliance, the labour, the flue, standard controls and VAT.

You will see lower numbers quoted elsewhere. Those are almost always the price of the appliance alone, at trade, and no homeowner pays that. Treating the box price as the cost of a new boiler is the single most common reason people are shocked by their first quote. Moving the boiler, removing a cylinder or a system flush all sit on top - the cost guide breaks it down.

The honest bit

Between the brands on this site the differences are real but modest. Who fits it matters more than what they fit. A mid-range boiler installed properly will outlast a premium one installed badly, every time, and most early failures are installation rather than manufacturing.

Which is the argument for getting three engineers to look at your house and tell you what they would put in it. It is free, it takes thirty seconds, and it is the only way to find out what the job is actually worth.