Heat pump systems have reverse-cycle technology meaning they can produce heating and cooling to your home. In cooling mode the heat pump creates cold water and pumps it to a fan coil unit. The fan coil unit transfers the chill from the water to air which flows through living areas via ducts in the ceiling.

Heat Pump – Heating

Heat Pump - Heating

Heat pump units use a refrigerant to transfer heat from one place to another. In the heating cycle:


  • Refrigerant enters the ground loop coils as a high pressure liquid
  • The refrigerant passes through an expansion device which causes instant pressure and the temperature of the liquid to drop
  • The liquid passes through the ground loops, absorbing heat from the surrounding earth, which causes refrigerant to boil off and change state into a vapour form.
  • This vapour is now a useable substance to be re-compressed into a high pressure/high temperature vapour by the system’s compressor.
  • The refrigerant is then used to heat your premises via a fan coil unit. Heat is transferred into the air passing over the copper finned coil and then distributed by ducting to heat your home.

Heat Pump – Cooling

Heat Pump - Cooling

In cooling mode the refrigeration cycle is reversed, meaning liquid refrigerant now enters the ducted fan coil unit via a refrigerant expansion device.


  • As high pressure liquid passes through this device it creates a sudden pressure and temperature drop in the refrigerant. The heat from your premises now passes over the copper finned evaporator coil.
  • Heat is absorbed into the refrigerant, creating cooler supply air and a change of state of this refrigerant.
  • The heat absorbed into the refrigerant is now transferred into the ground loops via the systems compressor.
  • Refrigerant passing through the ground loops is now dispensing heat into the earth causing a re-condensing effect in the refrigerant for the cycle to begin over.

Fan Coil Units

A fan coil unit is typically installed within an accessible ceiling void or services zone. The return air grille and supply air diffuser, typically set flush into the ceiling, will be ducted to and from the fan coil unit and thus allows a great degree of flexibility for locating the grilles to suit the ceiling layout and/or the partition layout within a space.
The coil receives hot or cold water from the heating/cooling source (e.g. heat pump) and removes heat from or adds heat to the air through heat transfer.
The fan coil units are controlled by a remotely wired thermostat.