Condensing clothes dryers don’t require a vent. Instead of blowing the moisture outdoors, these appliances use piped in cold water to provide a condensing surface. Condensed moisture is collected during the drying cycle and most commonly sent down the same drain used for the clothes washer. Some are stand-alone dryers, while others are washer-dryer combos with a single drum. These appliances usually include an electric-resistance heating element, just like conventional clothes dryer. Because condensing clothes dryers don’t vent to the outside, they aren’t pulling air out of the house that residents have paid to cool or heat. These dryers do take significantly longer than conventional dryers.