Marrying Radiant Heat With Wood

[DenisBarger]

I've lived in homes in Korea with radiant floor heating, which in every case consisted of water pipes running through a concrete slab. (A spongy linoleum made it more comfortable to lie or sit on the floor.) I've seen lots of This Old House projects with radiant heat beneath wood floors, but it doesn't seem to me that wood would transfer heat very efficiently. How does it compare with concrete?