A venting hose is usually made of temperature resistant plastic which is with metal. Ideally, once you position your portable air conditioner, the exhaust hose will need to be positioned to be directed out of the room to ensure that the hot air will be expelled.
Among many air conditioner manufacturers on the internet, there are claims to having portable air conditioners that don’t require venting.
Simply speaking, this is totally impossible.
Every portable ac unit needs a vent. The hot air that is expelled from the room which is being cooled has to be directed out.
A major reason why a portable conditioner requires venting is so that it can function properly and venting is inexpensive. In actual fact, most portable air conditioners come with an installation kit for a window.
One last note is that venting out of a dryer vent is not recommended by manufacturers as this could lead to a fire.