[Mikesolar]

Originally Posted by buffalobillpatrick

http://www.uponorpro.com/~/media/Ext...spx?sc_lang=en

See Table 15-1

They say turbulent flow starts with water around 8'/sec & stay below that speed.
Nominal 5/8" pex can deliver about 50% more heat than 1/2"

Use ECM pumps like Grundfos Alpha.

But the question is......do you need it? A typical 1/2" tube on 8" spacing with 110F water can give 50 btu/ft2. I'll bet Drakes home won't need more than 10-15btu max. There is no need to try to get the most heat out of a tube when it will only make your feet uncomfortable.