BASIX assesses the energy for air-conditioning based on:

  • whether it is a single-phase system or three-phase system;
  • for cooling, the cooling star rating or the Energy Efficiency Ratio (EER);
  • for heating, the heating star rating or the Coefficient of Performance (COP);
  • for systems that serve both the living areas and bedrooms, whether the system is day-night zoned between the areas.

If a reverse-cycle air-conditioner is to be installed for heating and cooling, the system needs to be described in both the heating and cooling sections of BASIX. The air conditioner may have a different energy efficiency rating for heating and cooling.

Air conditioning ducting needs to be installed in accordance with the relevant insulation and sealing requirements of the Building Code of Australia.


Some ducted air conditioning systems have the capacity to be zoned to function between "day-night". This means, the air conditioning will only be able to be used in the living areas during the day and in the bedrooms at night.

By incorporating a zoning feature the required size of the air conditioner is reduced and its use is reduced, since it either cools/heats one area or the other, and not both at once.

The larger the area to be cooled or heated, the larger the surface area between the conditioned space and the environment. This means that more energy will be needed to maintain comfort.

Zoning a building may also reduce the air leakage rate, saving more energy, as walls form barriers to internal air flow.

New energy ratings for air conditioners

A new star rating that varies for hot, average and cold climate zones, will be mandatory for all 1 phase, non-ducted air conditioners from 1st April 2020. (This has been voluntary since April 2019). For more information on the new climate-zoned star ratings and how to read the new energy-rating label, visit the Energy Rating website. 

Air conditioners registered before 1st April 2020 may carry the old star rating label and can be sold for the remainder of their 5‑year registration period.

If you have an existing BASIX Certificate that specifies an air conditioner rated under the old scheme, but you would like to change it to specify one rated with the new climate-zoned rating, you will need to revise your BASIX certificate.

Air conditioners rated under the old rating scheme will have different star rating than air conditioners rated under the new scheme. For example, an air conditioner rated 4 stars under the old scheme may only be rated 2.5 stars under the new climate zoned scheme.

If you want to select a product with a high star-rating, check it is available before making an energy efficiency rating selection for your air conditioner.

For air conditioners without a star rating, select the Energy Efficiency Ratio.