Selecting Air Conditioners

24 July 2018

Air conditioners are common household items nowadays in Singapore.  There are many different types and brands in the market and selecting the right type can be a headache for some,  particularly those  new apartment owners. This article will help these users  understand the various type and main differences between them so that they could select the correct type.

Types of Air Conditioners

Generally,  air conditioner for resident unit can be divided in to window air conditioning unit and  split air conditioning units.   

Among the window units,  there are the window mounted wall mounted window unit or casement window unit. 

Among the split air conditioning unit,  there are single split or multi-split air conditioning unit.  Then,  there is also ceiling mounted type which will not be covered here.

  Differences Between Window Unit or Split Unit Air Conditioning 

Detail Descriptions	Window Units	Split Units	Multi Split Units
1.  Type	The cooling and compressor  or condenser units are integrated	The cooling and compressor or condenser units are separated and linked by copper pipes	Same as Split Units except up to 5 Indoor units can be connected to one outdoor unit
2.  Installation	Usually installed under or next to the windows,  at arm’s or lower than arm’s level.	Usually installed above the window or at the ceiling with outdoor units on ledge or stainless steel support just outside the windows	The indoors units are connected to the outdoor unit via copper pipes through a control valve integrated with the outdoor unit
3.  Pipings	Not required	Insulated pipings are usually hidden inside PVC trunking running along the walls	Same as Split Units
4.  Power point	Required	Required with additional wiring for outdoor units running together with pipings in trunkings	Same as Split Units
5.  Noise control	Can be quite noisy	Only the outdoor unit runs abit noisy.   Indoor units are rather quiet.	Same as Split Units
6.  Cost	About 30% cheaper than split units	Total cost would be cheaper than multi-split	Total cost would be more expensive
7.  Energy Consumption	For the same type of compressor i.e. inverter vs inverter,  cheaper to operate	Higher consumption because of piping thermal and pump head losses.  Losses in pipe around 10 watts per metre run.	Energy consumption can be high if long pipings are required;  also,  the control valve may not control refrigeration flow properly if the valves are faulty.
8.  Verdict	Cheap and efficient for the same type except the operation is noisy	Good only when one has adequate space for separate outdoor units	Can save space of outdoor unit

 

 What to look for When Selecting  Efficiency Air Conditioner ?

 One of the most important factor in selecting air conditioner is based on energy consumption or how much electricity the air conditioners will consume.  In Singapore,  it is mandatory that each air conditioner unit must have the following energy label  so that the consumers can choose the right air conditioners.  Naturally,  the more the “Ticks”,  the more efficient will be the unit but  the higher the cost.  The consumers can also compare the annual energy cost which is specified in the label before they buy the right type of air conditioner. 

 Basic Consideration

 1.  Whether to install split air conditioners or window unit air conditioners for energy saving depend much on the design.   Basically,  if both air conditioning unit of the same power and  type (inverter vs inverter)  should consume the same amount of energy with split unit consuming slightly higher power because of the heat losses through the longer refrigeration piping.  On the other hand,  if the window unit is badly designed without proper segregation between cooling  and air intakes,  they can consume higher energy.  Window units generally is noisier.

2.  Whether to install multi-system or several single split system will depend much on the air conditioning usage and the heat load of the cooling space.  Multi-system usually have control valves distributing  refrigerants to various rooms; it will consume more energy in empty rooms as these  control valves do not always work efficiently to cut off refrigeration flow completely especially after some years of operation.  For example,  if one installed a  system-3 to always cool only 1 bedroom most of the time,  it will not only cost more but also  consume more electricity than 3 individual split unit.  

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