Which cylinder for this heat pump?

The figures we use

Per person

40 L

a day at 60 °C

Stored

50 °C

heat pump

Coil

0.25 m²

per kW

Occupants

beds + 1

people

A heat pump stores water at 50 °C rather than 60 °C, so the cylinder holds more for the same hot water, and holds the whole day's demand because it reheats slowly. Each bathroom after the first adds 30 litres a day. Every assumption is listed under the result.

Stored below 60 °C, the cylinder needs a regular thermal disinfection cycle set by the system's Legionella risk assessment (see our Legionella guide).