Many people assume that closing all doors when turning on the air conditioner helps keep the room cooler and saves electricity. At first, I thought the same way. However, after learning from experts, I realized this common habit can actually cause several problems for both your health and the efficiency of your AC system.

1. Poor Air Quality in a Sealed Room

When a room is completely closed while the air conditioner is running:

• Dust, bacteria, and other particles from the AC unit and the room itself can accumulate.

• Without ventilation, these contaminants stay trapped, making the indoor air 2–5 times more polluted than outside air, according to experts.

• Prolonged exposure to this poor air quality can harm your health, especially for children, the elderly, and people with respiratory conditions, increasing the risk of coughing, allergies, or other breathing problems.

Even if the air feels cool, it doesn’t mean it’s safe. A closed room can trap stale air, reduce oxygen levels slightly, and make the air feel stuffy or uncomfortable.

---

2. Increased Air Pressure Leads to Wasted Energy

Closing doors completely can also cause pressure buildup in the room:

• The cooled air pushes against cracks around windows, doors, walls, floors, and ceilings.

• This can cause the AC to work harder, consume more electricity, and sometimes unevenly cool the room.

• When the room reaches the preset temperature, the air conditioner temporarily stops cooling, but the air may feel insufficiently circulated, leading to stuffy and uncomfortable conditions.

In other words, sealing the room tightly doesn’t necessarily make the AC more efficient—it can actually reduce its performance.

---

3. How to Properly Ventilate While Using Air Conditioning

To balance comfort, efficiency, and air quality, follow these expert tips:

• Do not close doors immediately when starting the AC. Leave the door slightly open or cracked for about 10–15 minutes after turning on the unit. This allows dust and bacteria trapped inside the AC system to escape with airflow.

• Open doors briefly every 15–30 minutes. This lets the room “breathe” and exchange air with the outside without losing too much cooling.

• Create small vents or use fans for circulation. Proper airflow prevents uneven cooling, reduces pressure buildup, and helps the AC run more efficiently.

By combining slight ventilation with AC use, you can maintain cleaner air, improve comfort, and potentially lower electricity costs in the long run.

---

4. Take Breaks from Continuous AC Use

Even though it’s tempting to stay in a cool room during hot days:

• Experts recommend not staying in a sealed air-conditioned room for more than 4 hours at a time, because your body may struggle to adapt to sudden temperature changes.

• Every 2–3 hours, step outside for a few minutes to let your body adjust to natural temperature, which can help prevent fatigue, dizziness, or discomfort.

This simple habit helps maintain your body’s natural temperature regulation and reduces the risk of feeling cold or unwell after leaving the AC room.

---

5. Additional Tips for Comfortable and Safe AC Use

• Keep AC filters clean to reduce dust and bacteria.

• Consider using an air purifier or small ventilation fan to improve indoor air quality.

• Maintain a moderate temperature setting—extremely low settings can dry out the air and irritate your skin or respiratory system.

• Encourage light movement and fresh air exposure throughout the day for better health.

---

✅ Summary

By following these tips, you can enjoy a comfortable, energy-efficient, and healthier air-conditioned environment without risking poor indoor air quality or discomfort.