Combining low supply water temps with low-mass panel radiators.

This $47 million Minnesota project uses PEX tubing for its plumbing and hydronic systems. 

An engineer is planning underground insulated piping for a small district heating system, which receives heat from a central boiler plant and distributes it to three separate buildings. He is planning what he calls a “primary/secondary” piping system.

Where there is air, steam will not go.