Boiler Replacement Cost Calculator UK

Mid figure matches Gas Safe registered installer averages for 2024-2025. Variance ±20% reflects real quote spread. Site-specific factors not modelled: flue routing complexity, magnetic filter type, smart thermostat, system flush requirement.

The difference is the model line — Worcester has 4 tiers (4000, 7000i, 8000 Style, 8000 Lifestyle). The 4000 series sits in mid tier; the 8000 Lifestyle is premium. Always check the model number, not just the brand. The 8000 Lifestyle includes a 12-year warranty when installed by an Accredited Installer.

The Boiler Upgrade Scheme (BUS) gives £7,500 toward replacing a fossil-fuel boiler with a heat pump (not a new gas boiler). If you're considering a heat pump as an alternative, see our heat pump cost guide. Most homes still replace like-for-like as gas boilers are 1/3 the upfront cost of heat pumps.

Yes — magnetic filters (Magnaclean, Adey) capture metallic sludge before it reaches the boiler, extending its life and protecting the warranty. Most premium installers fit one as standard (~£250 installed). It's required for some manufacturer warranties (Worcester, Vaillant).

Like-for-like combi swap: 1 day. System change (e.g. regular → combi): 2-3 days. New install / major relocation: 3-5 days. Old boiler removal, new pipe routing, gas safety check, certification, and Building Regs notification (every install) included.