PEX is an acronym for crosslinked polyethylene. It is a flexible, durable, corrosion-resistant product that possesses distinctive properties that make it ideal for radiant floor heating and plumbing systems. There are three different types of PEX tubing: PEX-a, PEX-b and PEX-c. Uponor manufactures PEX-a tubing, which is considered the superior type of PEX in the industry. Unlike traditional heating systems that just warm the air, radiant heating warms the floor and the objects in contact with the floor. The entire floor distributes a consistent, even and quiet heating.