In a hydronic radiant heating and cooling system, warm or cool water flows through flexible plastic tubing called PEX that is located underneath or within the floors. (PEX is an acronym for crosslinked polyethylene.) The PEX tubing carries the water into specific areas or “zones” to effectively heat and cool people and objects located in every corner of the radiant area.
Uponor (formerly Wirsbo) was the first to bring radiant floor heating to North America more than 40 years ago. And the concept of radiant floor heating has been around since ancient Roman times. Radiant has been, and continues to be, used in many countries around the globe to effectively bring comfort in even the most extreme climates in the world.
The main components in a radiant heating and cooling system include a heat or cooling source, pumps, manifolds, PEX tubing and controls.
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 cooling as well as plumbing and multipurpose fire sprinkler 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.
All three PEX manufacturing processes generate tubing that is crosslinked to varying degrees and are acceptable for potable-water and hydronic radiant floor heating applications.
- PEX-a is manufactured using the Engel or peroxide method
- PEX-b is manufactured using the Silane method
- PEX-c is manufactured using the E-beam (electron beam) or radiation method
Uponor manufactures PEX-a tubing. The PEX tubing industry considers PEX-a superior because the crosslinking is done during the manufacturing process when polyethylene is in it amorphic state (above the crystalline melting point). Because of this, the degree of crosslinking reaches around 85% (higher than PEX-b or PEX-c), resulting in a more uniform, more flexible product with no weak links in the molecular chain.
Uponor PEX carries the following hydrostatic temperature and pressure ratings.
- 200°F (93.3°C) at 80 psi
- 180°F (82.2°C) at 100 psi
- 120°F (48.9°C) at 130 psi (½" tubing only)
- 73.4°F (23°C) at 160 psi
In accordance with ASTM F876 Standard Specification for Cross-linked Polyethylene (PEX) Tubing, the excessive temperature and pressure capability for Uponor AquaPEX® is 210°F (99°C) at 150 psi.
Yes. Uponor proudly backs the PEX tubing and ProPEX® fittings in its radiant heating system with a 30-year limited warranty when installed by an Uponor-trained professional.
Yes. Because water has a capacity to transport energy 3,500 times greater than air, a hydronic radiant heating system can bring comfort to a structure using less energy than a traditional forced-air system. This amounts to greater comfort at a lower thermostat setting, which provides lower energy costs. In fact, more people are comfortable with radiant heating at a lower thermostat setting and radiant cooling at a higher thermostat setting compared to forced-air systems. Additionally, a radiant heating and cooling system works in zones, allowing different areas of a structure to heat and cool at different times of the day. And hydronic radiant heating and cooling systems work well with sustainable solar, geothermal and waste-heat sources, making the system even more efficient.
Uponor partners with trade professionals who are trained and knowledgeable about radiant heating system design and installation. To find an Uponor-trained radiant floor heating system installer, visit our Find an Installer page.
Uponor can train your contractor on how to properly design and install a radiant floor heating system. To learn more about training opportunities for professional installers, call 800.321.4739 or visit www.uponorpro.com/training.