As the heat wave continues, concerns about rising electricity bills due to increased air conditioner usage are growing. Online discussions frequently suggest that "keeping the air conditioner on all day is cheaper than turning it off and on."
In short, this statement is only partially true. The power consumption of an air conditioner depends on whether it is an inverter type or a fixed-speed model, as well as how long the home is unoccupied.
Most recently released home air conditioners are inverter types. Inverter models use a significant amount of power initially to quickly lower the indoor temperature. Once the desired temperature is reached, they reduce the compressor speed to operate only as needed.
The issue arises when the air conditioner is turned off after the indoor space has cooled, only to be turned back on shortly after. If the power is off for a while and the indoor temperature rises, the air conditioner must restart at full capacity. Repeating this cycle can lead to higher power consumption compared to maintaining a steady temperature.
Researchers from Samsung Electronics presented findings at a conference of the Korean Society of Air-Conditioning and Refrigeration Engineers, indicating that for short outings of less than 90 minutes, it may be more energy-efficient to keep the inverter air conditioner running. Their experiments showed that after a 30-minute absence, power consumption was 5% higher when the unit was turned off and then restarted, and 2% higher after 60 minutes. However, after 90 minutes, it became more efficient to turn the unit off. Samsung noted that results may vary based on the home environment and insulation.
Thus, for inverter models, it may be beneficial to leave the unit on during short absences of 30 minutes to an hour. For longer absences of over two hours, it is generally better to turn it off.
The "90-minute" guideline is not a one-size-fits-all rule. Factors such as home size, insulation quality, window orientation, outside temperature, air conditioner capacity, and set temperature can all affect outcomes. Homes with strong sunlight or poor insulation will see indoor temperatures rise quickly after turning off the unit. Conversely, well-insulated homes can maintain cool air for a longer period.
Older fixed-speed air conditioners operate differently. They run at a constant output until the desired temperature is reached, then stop until the temperature rises again. Since they cannot adjust output finely like inverter models, keeping them on continuously may not be advantageous. Turning off a fixed-speed unit when the indoor space is sufficiently cool and restarting it when it gets warmer can help reduce power consumption.
To determine whether an air conditioner is inverter type, check the product or the label on the outdoor unit. If it is labeled "inverter" or shows cooling capacity and power consumption in multiple stages (minimum, medium, rated), it is likely an inverter model. The most accurate way to confirm is to check the model number or user manual or contact the manufacturer's customer service.
When first turning on the air conditioner, it is more efficient to use the high-speed or quick-cooling function to lower the indoor temperature rather than running it at a low setting for a long time. After reaching the desired temperature, it is advisable to set it around 26 to 28 degrees Fahrenheit and lower the fan speed to maintain that temperature.
Using a fan or circulator can help distribute cool air quickly throughout the room. The Korea Energy Agency recommends using air conditioners in conjunction with fans and keeping windows and doors closed during cooling to minimize the influx of hot air. When leaving during the day, closing curtains or blinds to block sunlight can also be beneficial.
Avoid setting the temperature too low. Setting the indoor temperature to 18 or 20 degrees does not make the air conditioner blow colder air. Instead, it may cause the outdoor unit to run at high capacity for longer, increasing power consumption.
Filter maintenance is also crucial. Clogged filters can obstruct airflow and reduce cooling efficiency. During the summer months when air conditioner usage is high, it is advisable to check and clean the filters every two weeks.
Electricity bills are not determined solely by the usage of one air conditioner. If the total power consumption in a household exceeds the progressive rate threshold, the cost of additional electricity usage can increase significantly. Korea Electric Power Corporation applies a progressive rate system, where the unit price rises as usage increases.
* This article has been translated by AI.
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