I have standard baseboard in my house that was designed for my oil furnace, so I assume it expects 180 degree water. Since installing my Tarm 4 years ago, my water is rarely 180 degrees, but we're never cold and we hardly burn any oil. I suspect we are in "circulation mode" more than we were with the oil, but it maintains temperature quite well, and the electric bill doesn't seem to indicate that the circ pumps cost much to operate. It does take longer to raise the temp a few degrees, and it's hard to get much above 70 when it's extremely cold out. Thankfully, we're ok with it around 70 most of the time.