Ground Source Heat Pump (GSHP) systems are an effective way to reduce a building’s heating and cooling energy consumption. However, sizing a GSHP system to effectively meet all of a building’s demand usually leads to an oversized system for the majority of any given year. Oversizing can result in an undesirable payback period. One aspect of a GSHP system’s design which inhibits a reasonable payback time is the inability to effectively operate the geo-field at reduced capacity. As a result, a GSHP system will tend to run at full capacity in short bursts at a time, rather than the more efficient alternative of running for longer intervals at reduced capacity. This study introduces a design modification to GSHP systems, called a ‘Smart Manifold’, which enables oversized geo-fields to dynamically resize themselves, allowing for more efficient operating conditions, while still being capable of satisfying building heating and cooling.