|
Because conditions vary, there is no precise answer to this question. The
electricity consumed by an air conditioner varies depending on a variety
of factors. Generally, you can expect to lower your energy consumption
by about 15% with this change. A rough calculation is as follows.
The amount of heat transfer is proportional to the differential between
the interior and exterior temperatures. Setting the thermostat at 27ºC
when the outside air temperature is 35ºC (the standard design
condition for air conditioners) results in a temperature differential
of 8ºC. Setting the thermostat to 28ºC results in
a differential of 7ºC. A simple calculation shows the amount
of incoming heat is 7/8 - in other words, 0.875 - indicating that the
air conditioner needs to remove 12.5% less heat.
As the temperature differential decreases, the air conditioner is moving
heat between two locations that have less difference in temperature; therefore,
a smaller amount of work is required to move the same amount of heat.
This effect can be calculated at about 3% per 1ºC.
Therefore, considering these two effects, increasing the setting by 1ºC
will reduce power consumption by about 15%. Setting the thermostat at
28ºC saves about 60% compared to a thermostat setting of 24ºC.
In practice, however, other factors come into play, such as the effect
of radiant heat, heat from office equipment in the room, and the heat
and humidity given off by people in the room. In addition, air conditioners
are often used when the outside temperature is lower than that assumed
by the designers. Because of these and other factors, the above rough
calculation may not reflect your actual situation. However, increasing
the setting by only 1ºC clearly leads to substantial energy
savings. |
