Unusual Room Size for Radiant

Tom Manton

My house is just about the same, 18' ceilings R32 walls, R 48 roof. I was a little concerned before I fired my radiant system up, but I can tell you it heats more evenly than anything else I can think of. Even heat at all heights from the floor, no stacking effect

virtualplumber

Large Ceiling height

I am installing a boiler and controls for an owner builder. He asked me to come in after the pex has been run. I ran a heat loss and punched in his tube lengths for pressures and temperatures. All is well except for his Great Room which is 18' tall. The house has an R 30 exterior wall and R 40 Ceiling. Good doors and Windows. Heat loss is 36,000 btus in Cleve. OH.
The room with the tall ceiling has suspended pex in the joists. 3/8's. The software calls for 170 degree water unless I drop the ceiling height 8'.

He is not concerned and tells me to just run it at the design temp for the rest of the floors. Which are only at 110 degrees. It is a modulating boiler so I can adjust the temp. the ceilng is open in the basement so extra pipe can be run. Any thoughts?

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ALH_4

Suspended tube

Pex in extruded plates. I know Radiant Engineering's Thermofin and Thinfin are both available for 3/8" tubing. I'm not sure about Uponor's Joist Track. Zurn, Viega, and Rehau also have extruded plates, but I'm not sure if they have plates for 3/8 tube.