Tips From Our Experts

Ducted Air Conditioning

Claire asks:

Is ducted air-conditioning is energy efficient. My understanding is that it is not as efficient as a regular split system air-conditioner, but I am not sure why this is the case. Could you please let me know if this assumption is correct and why this is the case?

Our expert’s answer

Thanks for your enquiry. Ducted air conditioning has a lot of inherent inefficiencies that are absent from split systems. The primary ones being that there are lots of losses in the ducts themselves due to:

  1. Air leaks in the ductwork/failure of the duct tape over time;
  2. Duct insulation being inadequate especially if the ducts are in the ceiling space where the temperature can be well over 60oC in summer;

You can also have:

  1. Difficulty in zoning efficiently;
  2. Modern split system units can have CoP/EER in excess of 4.5 and reaching 6 in some instances. (Higher figures are better) Central ducted air conditioners are lucky to have a CoP/EER of 2.5
  3. Ducted systems also waste energy just moving the air through the ducts and necessitate regular cleaning to avoid dust collection therein.

Split systems also allow you to heat your home in winter efficiently and economically, none more so than in Sydney where gas prices make ducted gas heating prohibitively expensive with losses from ductwork making this even more so.

Overall, a good split system (or a number of split systems) is far better from a standpoint of control, efficiency, avoidance of unnecessary losses and cleanliness.

John Knox

John Knox

The technical advice provided by the Alternative Technology Association as part of the ‘Ask an Expert’ forum/website, in relation to home and building sustainability improvements, is general in nature only. The impacts of specific energy or water saving or sustainability products will depend on how and where the are used and located, and particularly for larger investments, we would always suggest users seek a specific assessment from an appropriately qualified building designer or service / product supplier.

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