Buffer Tank vs Volumiser for Heat Pumps
Buffer tanks and volumisers are both used to increase water volume in heating systems, but they serve slightly different purposes. This guide explains the differences and when each option may be used.
Why Water Volume Matters
Heat pumps operate most efficiently when they run steadily rather than frequently switching on and off. Heating systems with very low water volume can sometimes cause short cycling, where the heat pump starts and stops repeatedly.
Increasing the amount of water in the system can help stabilise operation and improve performance.
Buffer Tank vs Volumiser
Buffer Tank
A buffer tank is a small water storage tank installed within the heating system. It increases water volume and can also separate different hydraulic circuits.
Buffer tanks are sometimes used when heating systems have multiple zones or when hydraulic separation is required.
Volumiser
A volumiser is a smaller tank installed directly in the heating circuit. Its primary purpose is simply to increase system water volume.
Volumisers are often used when a system needs a small increase in water volume but does not require hydraulic separation.
Key Differences
- Buffer tanks are usually larger
- Volumisers are smaller and simpler
- Buffer tanks can provide hydraulic separation
- Volumisers mainly increase water volume
In many modern heat pump systems, volumisers are used when additional water volume is required but system separation is not needed.
Do All Heat Pump Systems Need Them?
Not necessarily. Many heating systems already have sufficient water volume from radiators and pipework.
In these cases, additional tanks may not be required. System design and heat loss calculations are usually more important factors.
Estimate Your Heating Requirements
Use the HeatPick heat loss calculator to estimate radiator sizes and heat pump system requirements.
Use the Heat Loss Calculator