Not trying to stir any pots but for first time installs take this advice for what it's worth. I have a Heatmaster 20,000 heating my house (20') from the stove and a shed (200') from the stove. The twenty foot run to the house is supplied with the silver foil wrapped junk encased in 4" drain tile. I have a 4-5 degree heat loss on that twenty feet. Tonight,FreeHeat, a fellow forum member picked me up a maverick thermometer for use in my shed. The shed is supplied with two hundred,yes 200 feet of thermopex line. We checked the temp on the stove to guarentee calibration then headed to the shed. Once we had the thermometer taped to the supply line in the shed I called my wife at the house. She went to th stove(making fun of us woodstove nerds) and read me the stove temp. To my pleasure and FreeHeats dismay (he didn't use thermopex) the temps were both at 167 degrees. No heat loss on 200'! I couldn't be happier I just wish someone would have told me about this stuff when I hooked my house up. The price diffence is negligible considering the lifespan of underground supply and return lines.