We are currently working on a project that is utilizing a ground sourced Geo-Thermal Heat Pump HVAC system.
I am a big fan of these systems as they are unmatched for efficiency of operation. Geo systems are about 400% efficient as compared to the best LP systems which are about 95% efficient. In other words, for every dollar of energy purchased to operate the system (electricity for a Geo system) a Geo-Thermal system delivers four dollars worth of heat (the LP system delivers .95 cents worth of heat for every dollar of LP purchased)!
This system was designed and installed by Elco Geo-Thermal Heating of Bangor ME. It is an “Open Loop” system which utilizes the existing domestic supply well for its heat exchange source. Simply, water from the well is pumped to the heat pump, heat is extracted from the water, and then it is returned to the well.
The system delivers heat and air-conditioning via a ducted forced air delivery. As an added benefit, whenever the system is operating it also pre-heats domestic supply water as a free by-product which is then held in a storage tank until required which further reduces energy costs.
We have also added a Heat Recovery Ventilation (HRV) system which works in concert with the HVAC system to provide a continuous fresh air exchange into the building envelope while capturing much of the heat from the exhaust air being removed from the house.
These systems do cost more than typical Oil or LP boiler/furnace systems, however they currently enjoy a 30% Federal Tax Credit (through 2016) which makes the installed price very competitive and the return on investment time relatively short.
I am a big fan of these systems and we are specifying them in several upcoming projects, including our own home!