Geothermal systems have varying Cost to Install Geothermal HVAC depending on type. Horizontal loop systems are priced at an average of between $16,000 and 30,000 and they also occupy more land. Vertical loop systems are higher priced between 20,000 and 38000 or more because of the drilling requirements. Open-loop systems may cost 10-20,000 and rely on the presence of water. Both the types of systems possess their advantages and limitations and the ultimate cost depends on the conditions of the site and project needs.