Viessmann boilers.

What Viessmann are good at

Stainless steel heat exchanger rather than aluminium, which is the bit that usually decides how long a boiler lasts. Consistently top of reliability surveys.

What to watch

Fewer UK engineers fit them than Worcester or Ideal, so ask whether yours does.

Who they suit

People who intend to stay in the house and want the boiler to outlast the warranty.

What a Viessmann 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.