A natural-draft wire-and-tube condenser consists of a steel tube bended into a single-passage serpentine shape, with wires spotwelded perpendicularly on both sides. These heat exchangers may be assembled with tubes in a vertical or horizontal position and the air movement can be forced or natural. The forced-draft wire-on-tube condenser has usually a multi-passage serpentine shape, instead of a single-passage.  Since wire-and-tube condensers are relatively inexpensive, they have been widely applied in household refrigerators and freezers – appliances that consume a considerable amount of energy since hundreds of millions are currently in use, and dozens of millions are coming onto the market every year.

POLO has a wind tunnel to evaluate forced-draft heat exchanger effectiveness, as well as climate chambers to evaluate condensers installed in appliances.