Add-On Cooling System

Add-On Cooling Units: What You Need to Know

Add-on cooling units are designed to work alongside a ducted gas heating system, utilising the existing gas heater’s fan to circulate air across the cooling coil. While this may seem like a convenient solution, there are several important limitations and considerations to keep in mind.

Key Limitations

  1. Compatibility and Capacity
    Add-on cooling units can only be connected to certain ducted gas systems. The cooling capacity of the add-on unit is directly limited by the fan capacity of the gas heater, which restricts the size and effectiveness of the cooling system that can be installed.
  2. Energy Efficiency
    These systems are not standalone air conditioning units and, as a result, have poor energy efficiency. Unlike complete ducted air conditioning systems, add-on cooling units cannot be tested or rated in the same way. This means they do not need to comply with the same Minimum Energy Performance Standards (MEPS) as standard air conditioning systems.
  3. Nominal vs. Actual Capacity
    The cooling capacity advertised for add-on units is referred to as “nominal capacity.” This figure represents the system’s potential output under ideal conditions, without accounting for real-world losses. In practice, the actual cooling capacity is significantly lower due to factors such as:

    • Heat generated by the fan
    • Static duct pressure
    • System temperature variations
  4. Outdated Technology
    Add-on cooling units are the only type of air conditioning system still available with a non-inverter compressor. This outdated technology is less efficient and less effective compared to modern inverter-based systems.
  5. Misleading Energy Efficiency Ratings (EER)
    The Energy Efficiency Ratings (EER) provided in brochures for add-on cooling units are often misleading. These ratings are not measured in accordance with the AS/NZS3823.1.2 standard, which is mandatory for all other ducted air conditioning systems. As a result, the claimed efficiency does not reflect real-world performance.

Why Choose a Complete System?

For reliable, energy-efficient cooling, a complete ducted air conditioning system is the superior choice. These systems are designed to meet strict performance standards, deliver consistent cooling capacity, and operate with greater efficiency.

Floor-Standing Unit


These units are positioned on the floor against a wall. To operate efficiently, they need clear space in front of them. So they should not be positioned behind lounge suites or couches that obstruct the airflow. Some units can also be semi-recessed into the wall to make them less obtrusive.

Cassette Unit


These units fit neatly into the ceiling and are an ideal option to condition rooms where there are no available walls to mount a split system on or where there is limited ceiling space for a ducted system.

Flexi Unit


These units can be positioned on the wall at floor level or attached to the ceiling. The major benefit of these units is that they are highly practical in homes where wall and floor space is limited.

SIGN UP TO HEAR ABOUT OUR LATEST NEWS AND PROMOTIONS