PEX for cooling sub-floor

Mikesolar · 07-10-13, 06:14 AM

Defo, got to weigh in on this one. First, the only issue with PEX is that of the wall thickness and its conductivity. As there is a VERY large ratio between the surface area of the tube in an average system and the walls heat transfer, the only issue is the time it takes to transfer the heat and we have lots of time because all we have to do is match the heat load. As we know, this is easily done otherwise the Germans wouldn't have gone with the system to start with as the benefits and longevity of PEX outweigh copper in cement (preferred) over copper (or anything) and aluminum plates.

For best radiant cooling, running the cold water through a fin-tube rad with a drip pan underneath it would work well if the cooling load is not great. You must remove the humidity but to do so without a fan requires way more surface area. Floor heating controls exist for cooling but you still have to get rid of the humidity and watch the set point very carefully.

07-10-13, 06:14 AM	#9
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	Defo, got to weigh in on this one. First, the only issue with PEX is that of the wall thickness and its conductivity. As there is a VERY large ratio between the surface area of the tube in an average system and the walls heat transfer, the only issue is the time it takes to transfer the heat and we have lots of time because all we have to do is match the heat load. As we know, this is easily done otherwise the Germans wouldn't have gone with the system to start with as the benefits and longevity of PEX outweigh copper in cement (preferred) over copper (or anything) and aluminum plates. For best radiant cooling, running the cold water through a fin-tube rad with a drip pan underneath it would work well if the cooling load is not great. You must remove the humidity but to do so without a fan requires way more surface area. Floor heating controls exist for cooling but you still have to get rid of the humidity and watch the set point very carefully. Last edited by Mikesolar; 07-10-13 at 06:32 AM..