If you have investigated ground source geothermal as a potential energy conservation method to significantly impact your carbon and energy reduction goals you have undoubtedly had discussions regarding geothermal test wells and the resultant “K” factors relating to thermal conductivity. The important issue to thoroughly understand regarding the “K” factor in sizing geothermal well fields is that it’s only one of the variables that influence design. The value that can be achieved for a project using geothermal technology has to be based on a confluence of influential factors including: geology, hydrology, permitting, building load profiles, utility rate structure and client goals and objectives. These factors must be input into a robust institutional-based geothermal/building modeling process that will produce multiple scenarios early in the decision making process so that the institution can make an informed choice on whether to proceed or not. As an example if you have a “K” of 1.0 versus a “K” of 2.0 your well field size might be reduced in size by ~10-20% however if advanced modeling is utilized the well field could be reduced in size by up to 80% while maintaining up to 90% of the energy and carbon reduction goals. These results are achievable but they depend on the development and utilization of the influential factors listed above.