The main reasons for air conditioners not cooling are:

1. High room humidity with minimal temperature difference between indoor and outdoor.

2. Outdoor condenser surface is dirty.

3. The refrigeration system has air.

4. Insufficient Freon (commonly referred to as not enough snow type)

5. The air conditioner's power is insufficient, leading to inadequate cooling.

6. Extended periods without cleaning the filter result in reduced air flow.

7. Due to improper installation, the air conditioner's outdoor unit and indoor unit are connected by an excessively long copper tube. It is recommended to shorten the length of the copper tube between the outdoor and indoor units.

8. Voltage often does not reach normal levels; supply voltage is insufficient and unstable, particularly during peak electricity usage hours, when this issue tends to occur more frequently.