Does the average modern house air conditioner bring in air from outside, or just circulate the house air?

Question

In other words, is outside air brought into the air conditioner, cooled, and then blown into your house, or is it air that's already in the house, and cooled from that?

I ask because, if it is the second option, it wouldn't seem that you could get any fresh air that way.

Thank you in advance for your help.

Answer 1

The air inside the house is recirculated and de-humidified (dried) and cooled by the conditioner. No outside air is used.

Answer 2

Central air uses air from inside the house via the cold air return duct. This "recycled" air is then run thru your furnace filter.
Window a/c units also use recycled air unless the fresh air vent is opened. I do not recommend opening the fresh air vent when trying to cool the inside air. Opening the vent will make the unit work harder at trying to cool the air. The fresh air vent is for fan only use.

Answer 3

On a window A/C you will see a switch that controls a vent to open to outside air or closed just to re-circulate. Most of the modern central air A/C's pull in some fresh air but mostly they take the room air and re-circulate it until you get to the thermostat setting. If was 100 degrees out and 90 degrees in, you wouldn't want to keep trying to cool the 100 degree air.
bigbair70
Never let them see you sweat

Answer 4

Typically no outside air is introduced into the home. Only in unusual circumstances is outside air added. The only time I've seen it added to a home was when they were having a lot of moisture in the house. The A/C unit cycled off before it was able to take enough of the humidity out of the air. The unit was probably over sized which contributed to the problem. The outside air made the unit run longer to take more moisture out of the air.

Answer 5

On a typical residential system the inside air is constantly recirculated, no fresh air added. Most commercial systems bring in some outside air.

Answer 6

Air is pulled through your return duct inside the house through a filter. You don't need to have outside air in the house. It is VERY important to change your filter at least every 2-3 months and make sure your return is unobstructed. Never block return vent or close the doors around a return vent because the reduction in airflow is harmful to the unit or its efficiency. Because you have anywhere from several hundred to a few thousand sq ft of air accessible to your return, you don't need outside air.

Answer 7

The air is recirculated inside the house. You get plenty of fresh air every time you enter and exit the house.