What is flow temperature?
It is the temperature of the heating water leaving the heat source and travelling towards the radiators or underfloor heating. The return temperature is the temperature coming back to the heat source.
Why does it matter to a heat pump?
In general, a heat pump has to work harder to produce hotter water, particularly when the source temperature is low. Good system design therefore aims to meet the building's heat requirement at an appropriate flow temperature rather than simply setting the system as hot as possible.
Radiator size matters
A radiator emits less heat when supplied with cooler water. Heat-pump design therefore checks whether existing radiators can provide the required room output at the proposed design temperatures or whether changes are needed.
Underfloor heating
Underfloor heating uses a large emitter area and is often well suited to lower water temperatures, subject to correct design and controls.
Weather compensation
Many heat pumps vary the target flow temperature according to outdoor conditions. When the weather is milder, the system can use cooler water; when it is colder, the target increases according to the configured heating curve.
Heat pump expertise in Hull
Envirowarm works with air source and ground source systems across Hull and East Yorkshire. Read our heat pump servicing guide or explore our heat pump services.