One reason why an air conditioner is not cooling: insufficient refrigerant (also known as "snow seed" not enough)

This is a common occurrence, typically seen in air conditioners that are three to four years old. The AC doesn't stop cooling entirely, but the cooling effect is insufficient. This is due to the fact that older models use Freon as the refrigerant, which can evaporate over time. Additionally, there's a possibility of Freon leakage due to improper installation or inherent issues with the machine.

The Second Reason Why Air Conditioners Don't Cool: Insufficient Voltage Supply

Voltage instability is common, often failing to reach normal levels, especially during peak electricity usage times. Of course, this issue is beyond the scope of a technically skilled air conditioner repairman. We must address the problem by ensuring a stable power supply.

What to do if an air conditioner isn't cooling: Maintain a normal power voltage or choose a variable-frequency air conditioner. Why a variable-frequency air conditioner can solve the voltage issue can be found in the article "What Are the Benefits of Variable-Frequency Air Conditioners - A Comprehensive List of the Advantages."

Three Reasons Why Air Conditioners Don't Cool - Insufficient Power Rating

This is one of the common reasons for lack of cooling, but the causes for this can be varied, such as: a low-power air conditioner in a large room, or in some cases, the air conditioner's power seems to match the room size, but due to the room's relative openness (such as wide-open doors and windows), or the presence of heat sources inside the room (like multiple computers), of course, the western exposure of glass rooms can also be a heat source, and so on.