When BGG went to 3rd party test Passive Home builder Ed Marion‘s home, the coolest feature was his “near free energy machine”.

With a few turns of 3/4″ pex buried outside the foundation wall at footing level, he connected the loop to a in-line radiator with the incoming fresh air and filled the loop with glycol.The loop gather’s the ground’s heat and imparts it on the incoming cold air warming it significantly.

Using a wickedly efficient Grundfos circulator – drawing only 7 watts – on a -15°C he managed to get an 12°C temperature lift for the incoming air.

Ed’s perpetual energy machine

Shervin setting the baseline prior to the pressurisation and depresurisation tests for PH testing.