My system was installed in two phases. In April we installed the vertical ground loops for both the house and free standing office; one 270' bore for the office (1 12/ton) and 2-270' bores for the house (3-ton). We installed a "package" unit Climate Master 27 in the crawl space of the house and waited until October (for my money to catch up) to install the office Climate Master 20. We had record heat in Raleigh, NC this summer but my electrical consumption (for air conditioning) was down 49% during the billing period of June to August. And that was while I was still running the old 10 SEER A/C in the office! Winter temperatures have been mild so far this year but my October to December electrical cost has only increased by $20.00 a month (I was heating with propane before). My typical propane consumption has been 800 gallons/per year and this years quote for propane was $3.44/gallon (Amerigas Co). While one does not usually expect to have a "pay back" period for replacing an HVAC system it is clear that I will will and that it will be less than four years. The only mistake was using a packaged unit in the crawl space. Compressor noise transmits through the firewall into the blower compartment and is broadcast through the duct system. It sounds like a washing machine chugging away. An indoor "split" system would have prevented the noise transfer and the compressor cabinet could have been wrapped up in sound deadening foam, ha well, next time.