Geothermal: The Basics

At the heart of a geothermal system is the earth loop. An earth loop is the vehicle that transfers heat to and from the ground, distinguishing residential geothermal systems from conventional equipment.

There are many different forms of loops: vertical, horizontal, pond loops and open loops.

Vertical Loops are installed where space is limited. Holes are bored using a drilling rig, the pipe is inserted and the holes are filled. The pipes are connected horizontally a few feet below the surface.


Horizontal Loops are often used when adequate land surface is available. Depending on the geothermal systems’ needs and space available, pipes are placed in trenches that range in length from 100 to 400 feet.


Pond Loops can be installed if an adequately sized body of water is located close to the home. A series of coils are sunk to the bottom, connected by a header with supply and return pipes leading to the home.


Open Loops are used where there is an abundant supply of quality well water. The well must have enough capacity to provide adequate flow for both domestic use and the water furnace unit.