System-to-combi conversion typically £3,500–£4,800.

From £2,300–£2,450 (inc. standard kit)
Why pick it: Fantastic value range combi from the Vaillant Group — Vaillant-backed build quality with simple controls, compact footprint, and efficient performance. Often supplied in a pack (boiler + horizontal flue + filter) for extra value.
Warranty: Up to 10 years manufacturer warranty when installed/registered to scheme requirements and serviced annually.
Good for: Value seekers who still want Vaillant-group engineering and long cover.

Option: System-to-combi conversion typically £3,500–£4,800.