Condensers turn a gaseous vapor to a liquid. Any gas can be liquefied if the temperature is lowered enough or if it is pressurized. Condensers cool vapors enough to turn them into liquid.

Dry cleaning machines may use vapor condensers to cool evaporated cleaning solvents such as perchloroethylene for reuse. Without the condenser, the chemical vapor would be lost into the air and more chemicals purchased. Large storage tanks may use condensers to capture evaporated gases and return them to storage. This prevents Iowans from breathing the vapors and allows businesses to use the liquid for its intended purpose, reducing emissions and sometimes saving cost.