PEX Tubing comes in several different sizes. The most common sizes of PEX Pipe for Radiant Heat Systems is 3/8 Inch, 1/2 Inch, 5/8 Inch and 3/4 Inch. Generally, for residential Radiant Heat Systems we recommend 1/2 Inch PEX Tubing. The PEX Tube size dictates the flow rate that can be achieved and thus the maximum loop length of the pex tube. 1/2 Inch PEX Tubing accounts for the majority of Residential Radiant Heat installations and should be used in most slab, overpour, or joist underfloor heating applications.
5/8 Inch PEX and 3/4 PEX pipe are generally reserved for large commercial and snow-melt applications. This size PEX piping is also used for supply and return lines.
|Volume in gallons per 100 feet of tubing|
|*This table does not apply to PEX-AL-PEX Alumimun Tubing|
Maximum PEX Tubing Run Lenghts
3/8 inch PEX Pipe Loops should not be over 200 feet
1/2 inch PEX Pipe Loops should not be over 300 feet
5/8 inch PEX Pipe Loops should not be over 400 feet
3/4 inch PEX Pipe Loops should not be over 500 feet