Installing a geothermal heating system requires contractors to drill holes hundreds of feet into the earth. The drilling may pose as a problem for some homeowners, who live in a mountainous region. Usually drilling into rocky soil can be more costly that most homeowners are willing to spend. However, there are alternatives to drilling straight down into the earth. A geothermal heating ground loop can be installed horizontally, instead of the traditional vertical loop. In installing a horizontal loop, contractors will dig 5-foot deep trenches along your home, which are roughly a 100-feet long. This allows you to install geothermal energy without the drilling into the rock beneath your house. It is also cost effective since it is not as costly as drilling through feet of solid rock.