The cold air "stays open" vs. "On hand" which one is more cost-effective? Expert test tells you

Health     7:48am, 19 September 2025

In summer, the electricity used for cooling is to peak. If you want to save electricity, remember to turn off the cooling air at will. However, another way of saying it is to keep the cooling air moving more efficiently and save energy. Which answer is correct? We're here to hear what Japanese financial planners say.

The principle of cooling air transport

Financial planner Shi Bozi said in ITmedia that if you want to save electricity when blowing cooling air, you must first understand the operating principle of the air conditioner machine. Air conditioning is to circulate through refrigerant to disperse the heat in the room outdoors, thereby achieving the effect of reducing the temperature in the space, and the compressor responsible for cooling accounts for 80% of the electricity consumption of air conditioning.

If the cooling air is just started, the indoor temperature and the machine setting temperature difference will be larger. At this time, the compressor will quickly transport to achieve the set temperature, and consume the largest power, and then it will gradually flow stably.

So if you are just going out for a short time, it is recommended to keep the cooling air in the opening state first, so that the room temperature will not rise, resulting in more electricity consumption when the cooling air is turned on again.

Which is more cost-effective than "staying open" or "repeatedly turning off"?

Based on the experience of Dajin Kong's Hokkien, the day is divided into two periods: daytime (9:00-18:00) and nighttime (18:00-23:00). It was found that if the indoor temperature is set to 26°C, keeping the air cooler on for 30 minutes during the day is more power-saving than frequent switching, while in the evening, it is more power-saving when turning off the air cooler often.

will have such a drop, which is likely because the outdoor temperature drops at night, reducing the power consumption when the appliance is turned on. The test results show that if you only spend half an hour out during the day, don’t turn off the cold air at first, but it is recommended to close it at night.

Other ways to save air cooling during the period

1. Regularly clean filters

According to the Japanese Ministry of Energy, compared with blocked air cooling filters, cleaning the air cooling filters can save 990 days of GB (about 195 NT$) in a year. Generally, families recommend cleaning the filters once every two weeks.

2. Do not expose the outdoor machine to direct sunlight

If the outdoor machine is exposed to direct sunlight or strong light, the cooling air transfer efficiency will be reduced and more electricity will be consumed. It is recommended to negotiate with the installation staff whether the outdoor machine can be installed in the sun, or use cloth and other tools to block the sun, but be careful not to block the wind outlet of the outdoor machine.

3. When setting the wind volume to automatic

When using the cooling function, it is recommended to set the fan option to "automatic mode", so that the strong wind can quickly reduce the temperature in the room, and automatically switch to micro-styling after cooling.

According to the test of Da Metal Industry, the recommended air conditioning direction is set to "level". When the weather is hot, the wind is set to "strong", which is more efficient than reducing the temperature by 1 degree.

專家建議將冷氣風量調整為自動模式,風向設定為水平。圖/ingimage

4. The characteristics of air circulation using a circulation fan or an electric fan are: warm air rises and cold air decreases. The use of a circulation fan or an electric fan can help improve the phenomenon of uneven temperature and improve the efficiency of cooling.

5. Use windows to cover the sunlight

Many people like the feeling of sunlight falling into the room, but exposure to sunlight will increase the indoor temperature and reduce the cooling efficiency. It is recommended to use lace windows or leaf windows to cover the sun in hot summers. Remember to pull up the windows before leaving during the day. This way, when you turn on the air conditioner, you can also reduce power consumption when you turn on the air conditioner.