Do Window Air Conditioners Draw Air From Outside?

Do window air conditioners draw air from outside? The answer is no. Window air conditioners don't draw air from outside, but instead draw air from inside the house and circulate it around the room. The part of the unit that hangs outside is used to expel warm indoor air to the outside, leaving cold air in its place. Window ACs don't exchange air with the outside, they only exchange heat with the outside.

In other words, window air conditioners don't draw fresh air from outside, but instead filter, cool and recirculate the air in your home. Some of these ACs offer a vent lever option that allows fresh air to enter when needed. Before entering the room, air enters and passes through coils which cool the air. Warm indoor air is expelled to the outside through an exhaust system, leaving cold air behind.

Split system air conditioners, usually heat pumps, have part of the system located outside the house, but it does not absorb outside air. Outdoor air enters the system from an inlet that is usually located next to the oven, but is sometimes its own independent system. The main purpose of cooling the air in your home is not achieved by moving cold air indoors, but by expelling unwanted heat. When it comes to freshness, the air that comes from outside is full of potentially harmful elements.

If the air inside your home is warm or humid, spring and fall are the best times to open the window AC vent lever and let in some fresh air. Most window ACs come equipped with minimum efficiency report value filters which can only filter large particles. If the air is warmer inside the house than outside, this would be a great time to use ventilation and circulate colder air from outside and expel warmer air from the room.