Combi vs system vs conventional boilers
A combi heats water on demand with no tank or cylinder, suits smaller properties with one bathroom. A system boiler uses a hot water cylinder but no cold water tank, better where several taps might run at once. A conventional (regular) boiler uses both a tank and cylinder, common in older or larger properties, or where mains pressure is poor.
Gas fires and stoves — same Gas Safe rule applies
Installing or servicing a gas fire, gas stove, or gas oven/hob is gas work under the same legal framework as a boiler — it must be done by a Gas Safe registered engineer qualified in that specific appliance category, not just any gas-qualified engineer, since categories are appliance-specific.
Water-based underfloor heating and your boiler
A water-based underfloor heating system runs off the boiler via a manifold, usually at a lower flow temperature than radiators, and needs the floor buildup to accommodate the pipework. It's often more efficient paired with a heat pump than a gas boiler, because of that lower operating temperature.
Carbon monoxide safety
A carbon monoxide alarm should be fitted near any gas appliance, and tested regularly like a smoke alarm. Signs of a potential CO issue include a yellow/orange (rather than blue) gas flame, soot marks around an appliance, or unexplained headaches/nausea that ease when you leave the property — treat these as urgent.
Red flags in a cheap heating quote
A quote well below others is worth questioning — check it specifies a named boiler make and model (not just "combi boiler"), includes a powerflush if the system is older, and states the warranty length. No Gas Safe registration number offered unprompted is a clear red flag.
Common heating engineer jobs
Heating engineers install, service and repair boilers and central heating systems: annual boiler services, fault diagnosis, radiator installation and balancing, powerflushing, and full system replacements. Many also work on unvented hot water cylinders and, increasingly, heat pumps and other low-carbon heating.
How long should a boiler last, and when to replace vs repair
Most boilers last 10-15 years with regular servicing. As a rough guide, if a repair would cost more than a third of a new boiler's price, or the boiler is over 10-12 years old and parts are getting harder to source, replacement is usually the better long-term value than another repair.
Why Gas Safe registration is a legal requirement
Anyone installing, servicing or repairing a gas appliance or gas pipework in the UK must by law be on the Gas Safe Register, which replaced CORGI in 2009. This covers boilers, gas fires and gas cookers. Using an unregistered engineer for gas work isn't just risky, it's illegal, and any resulting certificate isn't valid.