Ans: The short answer to this is yes. Your portable AC will still work without a venting hose, but it will start heating the room since it doesn’t have an exhaust hose. When you remove the vent hose, the air conditioner alternates the cycles between cool and dry and hot and humid. This would heat up your room much more than it would chill down. If you must run the AC without a venting hose, run it in dehumidifier mode so it can remove the excess moisture and humidity from inside your room.