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.
What affects the cost
Cost depends on the type of system (combi vs system vs conventional), whether it's a straightforward swap or a full system change, boiler brand and output size, and property access. Moving a boiler's location, rather than replacing it in place, adds cost because of the extra pipework, flue routing and making good involved.
Solar thermal (hot water) systems
Solar thermal panels heat water directly (different from solar PV, which generates electricity) and work alongside a conventional boiler or immersion heater as backup for when there isn't enough sun. They need a compatible cylinder with an extra heating coil, so retrofitting to an existing system isn't always straightforward.
Grants and schemes for heating upgrades
Government schemes like the Boiler Upgrade Scheme offer grants toward heat pump installations (not gas boilers). Eligibility and amounts change, so check current details with your installer or the scheme's own guidance rather than assuming a figure quoted a while ago still applies.
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.
Air source heat pumps, what to know
A heat pump extracts heat from outside air even in cold weather, and typically runs at a lower flow temperature than a gas boiler, which usually means larger radiators or underfloor heating for the same comfort level. Installation is a bigger job than a boiler swap and government grant schemes (like the Boiler Upgrade Scheme) can offset some of the cost.
What a good heating quote should include
A proper quote should specify the boiler make and model (not just "a combi boiler"), whether a powerflush is included, the warranty length, and what certificate you'll receive on completion. If a quote is missing the boiler model, ask before agreeing.
When to replace vs keep existing radiators
Radiators themselves rarely need replacing unless damaged, corroded, or you're changing the property's heat demand (e.g. adding a heat pump, which often needs larger radiators to run at a lower temperature). A power flush can often extend a radiator's working life significantly cheaper than replacement.