I continuously fail to understand why the DX supporters believe that heat will travel through the earth faster if the source of the heat is the DX system.

There's no doubt that the interface between copper and the earth is far superior to an HDPE pipe to earth interface. But, once the heat is through the copper-to-earth interface it has to travel through the earth. And it's not going to travel any faster than if it came from an HDPE pipe full of water.

DX tubing is limited in length and surface area. What you need is more, not less, DX tubing to make it work, to get the heat spread amongst a greater amount of earth.

Science and physics principles tell me that capacity is very limited for a well working DX system.

Best regards,

Bill