The house is mostly passively heated and cooled. Its back wall is 8 feet below grade and it has a large south face of windows to collect passive solar heating. It stays always above 55F in winter without any heating, frequently reaching 65 on sunny winter days.

In summer, the tile floors are gloriously cool and the house needs no air conditioning despite being located in the southern Applachians. (There are some moisture problems in summer though.) Overhead fans (24V DC) aid in summer airflow.

The hot water heater, being a hybrid heat pump water heater, can also cool the house when it's running in heat pump mode. As a bonus, it's in the same room as the inverter, so when the inverter heats up due to prolonged major loads, the heat gets captured and pumped into the water heater.

In winter, wood heat suppliment the passive solar. A couple pickup loads of firewood will last all winter. I sometimes gather firewood on the property using a battery powered chainsaw.