A vertical loop is another variation of the closed ground loop and is installed by drilling vertical boreholes 100 to 300 feet down into the ground, and putting a loop of pipe down it. When the pipe is in, a special thermal-conductive grout is pumped into to ensure uniform contact with the earth, which ensures efficient heat transfer between the earth and the ground loop.
This method is typically more expensive to install than other methods, because of the large amounts of vertical drilling, but is very effective in situations where land is limited.
The size and number of loops in a vertical system is mainly dependent on the heating load needed, as well as static water level and the type of soil it will be drilled through.
Having a well driller that has experience in drilling thermal bore holes, not just wells, is very important.