Buildings Guide

Space Cooling  »  Unitary (DX) Air-conditioners


There were an estimated 550 to 600 million DX units in the form of room air conditioners and packaged ducted air conditioners installed worldwide at the end of 2009 (IEA, 2011). Annual sales of these air conditioners were around 55 million (including reversible units) in 2009 (IEA, 2010). The best split units have a COP of around 6 compared to average sales weighted efficiencies of around 3.5 or less. In simplistic terms this equates to a potential saving of around 40%, although savings in real usage could be more or less than this when seasonal efficiencies and regional variations are taken into account. The IEA estimated global energy consumption by residential air conditioning systems (chiefly DX systems) could be reduced by approximately 877 TWh/yr by the year 2050 with stringent policy action when compared to a 2007 baseline scenario (IEA, 2011).

Volume of global air conditioner market, by product type, in millions of units
Volume of global air conditioner market, by product type, in millions of units
Source: BSRIA, 2013


If units are grouped according to technical and performance similarity, there are four main types of vapour compression air conditioners. They are listed below in descending order of sales % (BSRIA, 2010) Non-ducted splits (single type, also called ductless mini-splits)

  • Non-ducted multi-splits (also called ductless mini-splits)
  • Ducted splits (US style mini-splits)
  • Non-ducted unitary (also called packaged-single); Includes window, through the wall, packaged terminal air conditioner (PTAC)
  • Single duct / double duct (including mobile)

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