Why Does Car AC Feel Humid Inside?

To understand as to why your Car AC feels humid inside, you must be aware that the car’s air conditioning system does not just cool the air, but is also dehumidifying it. As warm, moist air from the cabin passes over the cold evaporator coil, the moisture condenses into water.

This water then drips down into drain pan and it is expelled from the vehicle; it is usually a small puddle under your car when parked. The cooled, dried air then was blown into the cabin, thus making it feel comfortable.

When this process is not working right, the humidity remains in the air or the water is not draining away efficiently.

Low Refrigerant (GAS) levels : this is perhaps the most common reason for underperforming AC Refrigerant is the lifeblood of your Ac system, it is what absorbs heat as well as humidity from the air. If the levels are too low because of a leak, the evaporator coil won't get cold enough to properly condense the moisture, thus leading to less cooling and less dehumidification. The air would feel cool, but still damp.

Blocked Evaporator Drain: As mentioned, condensed water requires to drain out of your car. If the drain tube, often a small rubber hose, becomes blocked with dirt, debris or even mould, the water can back up. This means the moisture stays within the system, re0evarporating into the cabin air or even saturating carpets and floor mats, leading to a true dam feeling and potential mould growth.

Failing Blower Motor: The blower motor pushes the air over the evaporator coil and also into the cabin. If it is weak or it is not functioning correctly, air will not circulate efficently. This can lead to inadequate cooling and dehumidifcation, as this not enough air is being processed by the coil.