Three seperate 2-speed ground source heat pumps by Florida Heat Pump. They share nine 320ft vertical loops with no antifreeze. Loop sized to maintain 50+ degrees even during severe winter use providing 5.2+ actual COP all winter. 3rd stage electric heat strips for emergency. 11 seperate forced air zones.
Large south oriented windows provide enough passive solar to completely heat house from 10am to sunset on sunny winter days above 30 degrees. There is 6'' thick exterior stone on southern walls to maintain heat into evening. Deep roof overhang shields sun in summer.
HAI intellegent staging thermostats used to maintain the more efficient low speed HP operation as much as possible. They only add stage 2 when user specified heat rise rate is not being met in stage 1.