If you have ever wondered why your air conditioner (AC) unit pressurizes, you are not alone. Many people do not know that there is a scientific reason behind this common occurrence. In short, the answer to this question is physics. By understanding a little bit about how AC units work, it is easy to see why they pressurize when in use.
An AC unit uses refrigerant to cool the air inside of a home or building. This refrigerant is kept in a closed system of coils and tubes. When the AC unit is turned on, the refrigerant begins to flow through these coils and tubes. As the refrigerant flows, it picks up heat from the air around it. This process continues until the coils and tubes are full of cold air.
The cooled air then needs somewhere to go so that the process can continue cooling down more air. The only place for this cold air to go is into your home or building through the vents. As more and more cold air enters the building, the pressure inside begins to increase. That is why you may notice that your doors or windows seem harder to open when your AC unit is running - because of the increased pressure inside caused by all of that cold air!
So there you have it! The next time you notice your AC unit pressurizing your home or office, now you will know exactly what is happening and why!