Why surveys sometimes overstate the need
Heat pumps run at lower flow temperatures than gas boilers, so older radiators can deliver less heat. Surveys often recommend bigger units or underfloor heating to compensate. Yet some homeowners report their existing radiators already cope fine when the boiler is turned down to 55°C, the temperature a heat pump would use. Overly cautious heat-loss calculations appear to be driving some of these calls.
Simple checks before you commit
Lower your boiler's flow temperature to around 55°C and leave radiator valves fully open. If the house stays comfortable, your current emitters may be adequate. Always insist on room-by-room heat-loss calculations that follow the latest BS 12831:2017 standard and meet MCS requirements. Getting several quotes helps spot when estimates look inflated.
Real costs and smarter alternatives
The £7,500 Boiler Upgrade Scheme grant covers the heat pump itself but leaves radiator work as an extra bill. Improving loft, cavity or floor insulation first can cut the heat demand and sometimes remove the need for new emitters altogether. Running the system steadily at lower temperatures, rather than in bursts, also keeps bills down.
Where to start
Compare tariffs and see current grant rules on our energy pages. Question any survey that wants big radiator changes without clear evidence your home actually needs them.
