How to calculate the required buffer tank volume

The correct buffer tank volume depends on the heat pump's power, the minimum runtime, and the permissible temperature range.

Basic logic

The higher the unit's minimum power and the lower the active load, the more water may be required.

Minimum water volume

Many manufacturers provide a minimum required water volume or minimum flow rate in the manual.

Practical selection

The final volume should be based on the data for the specific model and not on a general rule of liters per kW.