Another option is water. Water is cheap, and you can pile up gallon jugs of it. Or use your pond/swimming pool.
Geothermal HVAC makes use of the thermal mass of rocks and dirt, too.
Another option is water. Water is cheap, and you can pile up gallon jugs of it. Or use your pond/swimming pool.
Geothermal HVAC makes use of the thermal mass of rocks and dirt, too.