Thanks Mike,Travis and Chiller.

I will keep that tube spacing in mind Mike...

I have the same concern Travis with condesation and have read and suggested using an A/H off the the HP for humidity removal an air tempering. The engineers "from Portland" don't seem to feel that it's an issue and therfore the owners are saying no forced air. I haven't talked with them since we were awarded the job though, and we are on hold right now from H/O family issues. I will definitely plead the case and get it all down in writing either way.

Chiller it is a small niche right now, but is growing. Where it stops, how long it takes who knows. I remember a house my parents built when I was a kid in the 60's in Cali with radiant, using galvi pipe. Then radiant all but dissapeared here in residentual until a better cost effective material evolved "pex". It may not be in our time it takes hold but it will be us that determines why or why not.