Energy usage is roughly one third that of refrigerated systems. Evaporative coolers are cheaper to install and maintain. Most of the time the home owner can perform routine maintenance and if maintained properly the unit brings fresh moist air into the home, providing a healthy environment for plants and animals. The refrigeration cooling at the Desert House is a heat pump air conditioning system. Unlike the evaporative system described above, the heat pump provides cool dry air during the cooling season and warm dry air during the heating season.
Heat naturally flows from warm areas to cool areas until a temperature equilibrium is reached.
During hot weather, freon, a refrigerant, is kept quite cold in an interior coil. The freon absorbs heat from warm air passing through the coil, the cool air is circulated through the house by the fan. The heated refrigerant is pumped to the outdoor coil and heat is dissipated into the atmosphere. To heat the interior, during the cold season, the process is reversed. Refrigerant absorbs heat from the outside at the outdoor coil, and is pumped into the building interior where cool air is heated at the indoor fan coil.