Different types of PEX tubing
Non-Barrier or "Plumbing" PEX
This is the standard PEX type used in plumbing systems for hot and cold water distribution. Plumbing PEX tubing usually comes in red and blue colors to help installer distinguish between the hot and cold water piping. This type is not suitable for traditional closed-loop heating applications.
PEX with O2 (Oxygen) Barrier
Has an external coating of EVOH polymer, which creates a barrier around the pipe, preventing permeation of oxygen into water through the pipes’ walls and prevents decomposition of cast iron elements and formation of rust. This type is used strictly for heating applications and is not intended for potable water plumbing.
A composite type pipe comprised of 3 layers - PEX, aluminum and PEX bonded together. This is the only PEX type which exhibits “memory” properties and keeps the shape it was bent to. Smaller diameters can be used with pre-manufactured plywood panels; larger - for wood boiler and furnace lines.
Advantages of PEX
PEX in Plumbing
One of the most important and distinctive advantages of PEX tubing over traditional copper plumbing is its cost. A typical 3/4" size “L” type copper pipe runs today for about $2.00/ft, whereas PEX is less than $0.50/ft, which is a four times difference in price.
Unlike rigid copper, brass and CPVC pipes, PEX is flexible and requires a fraction of the quantity of fittings used in rigid pipe installations, which further reduces material costs, produces more pressure at the fixture and significantly cuts installation time.
Due to the nature of PEX piping, it expands and contracts more then copper and brass pipes and is able to absorb more thermal stress produced by changes in water temperature. As a result, PEX has more resistance to bursting from water freezing inside the pipes and eliminates the issue of “singing pipes”.
PEX in Heating
There are no good alternatives to PEX tubing in the radiant floor heating industry. Warm floor systems are more efficient than all other types of heating systems and produce the highest comfort level available.
In hydronic baseboard and radiator systems, PEX tube can easily replace copper pipes with less material costs and installation time.
While most PEX manufacturers only offer 20-25 year warranty, the expected lifespan of the pipe is estimated to be around 50 years, as long as it’s properly installed, kept away from sunlight and used within approved temperature and pressure ranges.
How “lead-free” regulations are affecting PEX
Everhot non-barrier PEX was and remains compliant with the “lead-free” regulations taking effect in 2014 and is NSF approved and certified for drinking water applications nationwide. Sioux Chief and Viega PEX pipe are also lead-free compliant and approved for drinking water applications (non-barrier PEX).