I stapled up 750' of 1/2" pex on the bottom of my floor. It is under the whole living room , kitchen, and master bathroom floor. It gives the house a very warm feel and I can't quite explain what I mean,, just more comfortable. My question is though, is that many say it's more eficient than forced air. I am looking to see if anyone has done this and have you seen less wood usage sinse going to hydronic floor heat?? One other thing. I went 8" OC under the carpet but went 16" OC under the wood and ceramic tile in the master bath. The 16" OC works enough to take the chill off the floor but not much more.