12 models, 7 to 65kW
compact design

AquaMaster Inverter

5 models, 3 to 48kW
variable speed control

AquaMaster Inverter Combi

9 models, 3 to 23kW
integral DHW tank

Ground Source Heat Pumps (Ground-Water)

Ground Source Heat Pumps (GSHP) Explained

A Ground Source Heat Pump (GSHP) harnesses latent heat stored in the ground through circulating water/brine*. The heated water/brine is taken to the heat pump where it is condesned and compressed. The heat is transferred from the water/brine* to stored hot water. The cooled water/brine* is circulated back into the head of the collector for re-heating. This cycle repeats continuously. All components are housed within a single unit located inside the building.
*brine is the name given to the water/anti-freeze mix.


  • Higher capital cost
  • Trenchwork/drilling required


  • Less susceptible to weather change
  • Longer service life
  • Reduce energy bills by up to 75%
  • Ultra silent operation
  • Eligible for RHI


Requirements for ground loop: horizontal collector

Heat pump + horizontal collector

The size of land required for the construction of power depends on the heat pump and soil properties. The higher the humidity/water content, the larger the energy yield.

Generally, for every 1kW of heat you will need approximately 60 square meters of land. Slinky collector is one of the more convenient forms of horizontal collector, as illustrated below.

Requirements for ground loop: vertical collector (borehole)

Heat pump + vertical collector (borehole)

When outdoor space is limited or the building suffers extreme temperatures, we would recommend installing geothermal boreholes. Here, the ground collector is dropped into geothermal boreholes to harness heat deep from the ground.

The maximum depth of the well is dependant upon the driller, we would recommend a maximum of 100m per loop.

Generally, for every 1kW of heat you will need approximately 20m of geothermal

Sizing ground-water heat pumps

The AquaMaster range can be used in either a monovalent system, or bivalent. They have the capacity to provide 100% of the heating and hot water requirement when sized correctly. It is critical that the ground collector be sized according to house demand and not the capacity of the heat pump. oéí

How to maximise your savings

1st The heat pump

The heat pump must be sized to meet 100% of the demand of a building. Oversizing and undersizing may result in excessive running costs. MasterTherm Online Control combined with the latest technology and a robust design allows us to offer 7-year warranty on all parts of the heat pump. MasterTherm heat pumps must only be installed by certified personnel. For units under 45kW, please ensure that your installer is a member of the microgeneration certification scheme (MCS).

2nd Efficiency or heating factor (COP)

The higher the input temperature of the heat pump and the lower the output temperature, the higher the efficiency. A desuperheater can, when fitted, produce higher and more efficient domestic hot water. Hot water runs when the compressor is running as a "byproduct" to heat domestic hot water.

3rd System solutions

MasterTherm heat pumps are designed and equipped with control and pumps to circulate heat to the desired distribution system. There is no requirement to incude additional pumps. Everything required is included in the appliance. Simple and reliable installation.

High Efficiency Heat Pumps - AQ30I, COP of 4.6 at B0W35

Inverter technology with the latest BLDC compressors and electronic injection pushes the performance, and increases the overall efficiency. Expect all the usual MasterTherm refinements including 7 year warranty and internet control.

AquaMaster Inverter