Running Costs
Find out which heat pump settings could be driving up your energy bills.
A high flow temperature is one of the most common reasons a heat pump can cost more to run than expected. Some systems may be configured to operate at around 55–60°C, but heat pumps generally operate more efficiently at lower flow temperatures, often around 35–45°C, provided the home can still reach a comfortable temperature.
Lowering the heat pump flow temperature can reduce electricity consumption and improve efficiency. The exact saving depends on your heat pump, heating system, insulation, outdoor temperature and controls, so a 60°C flow temperature should not be assumed to cost exactly twice as much as 40°C in every home.
Weather compensation automatically adjusts your heat pump’s flow temperature in response to the outside temperature. It increases the flow temperature when the weather is colder and reduces it during milder conditions, helping the system run efficiently while maintaining a comfortable indoor temperature. Your installer should set the heating curve during commissioning, but an incorrectly configured curve can increase heat pump running costs. If you are unsure whether it is enabled or correctly configured, ask your installer or the manufacturer’s technical support team to check it.
The electricity tariff you use can have a major impact on heat pump running costs. Specialist heat pump and time-of-use tariffs can offer cheaper electricity during periods when your heat pump is most likely to operate, potentially reducing your annual energy bills. Energy Saving Trust research found that choosing an appropriate heat pump tariff can deliver significant savings compared with standard tariffs. Check the current rates, qualifying conditions, standing charge and any off-peak hours before switching.
Your heat pump’s immersion heater is designed as a backup or supplementary source of heat, so frequent unnecessary use can increase electricity consumption and heating costs. Check your controller or app to see when the immersion heater is operating and whether a heating boost or hot-water setting is triggering it more often than necessary. Do not disable the system’s required hot-water sterilisation (Legionella protection) cycle simply to reduce electricity use; this should be programmed to run safely at an appropriate time, ideally when electricity is cheaper.