No, single hose portable air conditioners do not pull air from outside. These types of portable air conditioners operate by drawing in warm air from the room they are placed in, cooling it through the refrigeration process, and then expelling the hot air and moisture generated during the cooling process through a single exhaust hose.
The process works as follows:
The portable air conditioner takes in warm air from the room through the front intake grille.
The warm air is directed over the evaporator coil, where it is cooled and dehumidified.
The cooled air is then blown back into the room through the front of the unit, providing the cooling effect.
The hot air and excess moisture produced during the cooling process are expelled through the single exhaust hose, which is usually directed out of a window or an opening in the room.
Because single hose portable air conditioners expel hot air and moisture outside, they create a slight negative pressure in the room, which can cause some warm air from the outside to be drawn in through any gaps or openings (like under doors or around windows). However, the primary air circulation and cooling process in these units are confined to the air within the room they are operating in.