Seeking insulated PEX recommendations for hydronic heating/cooling
So after discussions about the relative costs of labour for different tasks in my electric retrofit, I’m starting to swing back around to ATW rather than mini-split, as with a monoblock design we can avoid refrigerant line runs altogether. Even though the equipment cost is a bit higher, as we run the numbers, it’s starting to look like ATW may win out overall with a faster, less-disruptive install (just like John Siegenthaler says!)
The leading contender right now has us installing home-run PEX lines to a combination of ductless slim wall-mount hydronic fan-coil air handlers to handle both heating and cooling, and a few replacement wall-mount low-temp radiators for the rooms where I need just a bit more oomph in the winter but don’t need to worry about cooling in the summer.
Design temperatures will be 7C (45F) for cooling, and probably 50C (120F) for heating. Most runs will be around 30-50 ft, heading into 1/” NPT on the air handlers. Each air handler or radiator will need 2 pipes — 1 outgoing, 1 incoming. The PEX will ideally run through wall cavities where possible, but in small soffits where it’s not.
I’ve been looking for a good solution for insulating these runs, both to avoid heat loss as well as to prevent condensation during cooling. I’ve found solutions such as Uponor Ecoflex with 2 PEX pipes embedded in foam, but these seem primarily oriented towards outdoor (buried or not) runs, and also seem fairly bulky. I’ve also seen solar-oriented solutions with pairs of steel pipe wrapped in EPDM. There’s also single-pipe solutions such as Cool-Fit from GFPS. And of course, there’s good old fashioned 6′ segments of pipe insulation (rubber or foam) as well as pipe wrap. However, I’m leery of the manual approach both from an anti-condensation point of view as well as labour.
Do you folks have any recommendations for pre-insulated PEX which would be suitable or have any comments about this?
Thank you all in advance for your help.
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