Swamp coolers do need to be vented in order to release the hot air. If they are not vented, the hot air will build up and cause the cooler to work harder than it should, which could lead to damage. It's also important to make sure that the cooler is properly sealed so that the cold air doesn't escape.

Yes, the swamp coolers need to be vented. The hot, moist air that is created by the cooler needs to escape so that fresh air can come in and cool the interior of your home. If the hot air is not allowed to escape, it will just recirculate inside and make your home even hotter.