Used everyday, the air conditioner easily becomes the largest energy consumer of a household. Therefore, in general, it is preferable to use natural ventilation where possible. For example, we can open the windows once the outside air has become cooler or close the curtains during the day so as to prevent heat from entering. Here are some additional tips to save energy and money with the AC. Set the thermostat as high as comfortably possible.

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  1. The lesser the difference between the inner and outer temperature, the lesser the amount of power the AC will draw.
  2. Close all doors and windows around the area to be cooled. Closets and cupboards should also be closed since, if left open, the AC will use extra energy to unnecessarily cool the space inside them.
  3. Clean AC filters regularly since clogged filters can increase power consumption by up to 5%.
    If possible, put off jobs that produce heat (cooking and ironing) until the cooler times of the day.
  4. Shade air conditioners. ACs that operate in sunlight consume up to 10% more energy than same ones operating in the shade.
    Remember to set your timer so that the unit does not remain on unnecessarily.
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Another important factor that greatly influences the amount of power an air conditioner draws is its size. The size, or capacity, of an air conditioner is measured in BTUs (British Thermal Units). The BTU rating represents the volume of air, in cubic feet, which will have its temperature reduced by one degree in one hour. For example, a 20,000 BTU air conditioner is supposed to be able to reduce the temperature of 20,000 cubic feet of air by 1 degree in 1 hour. Now, for a unit to operate in the most efficient manner possible, its capacity must be neither too big nor too small for the space it has to cool. An AC that is too large will too rapidly cool the room and consequently cycle off before having sufficiently dehumidified the air. A small unit, on the other hand, may not have enough BTUs to cool a room and will therefore tend to keep on running (this will, of course, impact negatively on your bill).

The procedure to determine the optimum unit size for a particular room can be quite involved since a rigorous approach would require such parameters as the volume of the room, the number of windows and where they are situated, the kind of exposure of the room to sunlight, the insulation of the room, the number of occupants and the general climate of the area. However, as a rule of thumb, CEB tells us that 600 BTU are sufficient for cooling a surface of . Thus, a room with a surface area of 15 will require a unit with a capacity of 9000 BTU.

Air conditioner maintenance

For an air conditioner to operate efficiently; it must be regularly maintained. Maintenance can help detect problems at an early stage and thus prevent expensive breakdowns later on. Therefore, it is important that, every year or so, a qualified technician be hired to check the following:


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  1. Is the Freon level adequate? Freon is a refrigerant that is used to cool the air conditioner’s compressor. Low Freon levels will decrease the efficiency of the unit and, worse still, may cause the compressor to overheat and eventually breakdown.
  2. Insufficient Freon levels are the result of leakage/s that must be eliminated before the refrigerant level is restored.
  3. Are the filters clean? Clogged filters can decrease the efficiency of a unit by up to 5%.
    Is the thermostat correctly calibrated?
  4. Are all electrical and mechanical components functioning properly?
    Hiring a technician to perform the above check-up does cost money. However, this is money well-spent since a well-maintained air conditioner will cost less to run and last longer as well.
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