We've spent the last week installing radiant or hydronic heat pipe on the slab. We're using 1/2" Oxygen Barrier PEX for the tubing. I used LoopCad to do the intial layout using a 30 day trial period license. Our GC didn't want any of the tubing to go under interior walls so I had to modify the routing to suit. We spent the first day just laying out the floor plan on the vapor barrier using green paint. The next day we started the effort of installing the PEX under the rebar -- another requirement of the GC. Uncoiling the PEX was certainly a challenge -- especially in the cold. Commercial PEX unwinders cost around $700 and the local rental centers didn't have any for rent. After searching the internet and YouTube Maddog had a good suggestion. After getting the materials needed to make the unwinder we put it together in about a half and hour. What a game changer! I'll put together a subsequent post and video of how we constructed it. The one we based it on was inexpensive -- this one cost about $25...and it works just fine. We estimate the cost save for us to install the radiant heat is around $40,000.