text: Pithouses were built by excavating a well defined hole into the ground, usually around 6" to 18" deep but occasionally as deep as four to five feet, and creating walls and roof using a pole and adobe technology. The sunken floor of the dwelling is below the frost line and helps moderate both winter and summer temperatures, with the mass of the ground serving as an insulator. In addition, adobe walls gather heat during the day and release it when temperatures drop. The earliest pithouses were round, and varied in size between nine and twenty-five feet in diameter. Around 700, pithouse designs became more individualized. Excavations reveal examples based on squares, rectangles and shapes similar to the letter D.
  These homes were also warmed by a centralized hearth, a fire pit with an air deflector, and side vents and a smoke hole in the roof provided fresh air and evacuated smoke. The placement of the home's entrance varied by locality and archaeological period. Early homes utilized the ventilation stack as an egress by means of a ladder. Later homes expanded the pit into a keyhole shape to create a low sheltered entrance. Interior space was often loosely divided into two rooms, one for storing personal and dry goods and the other as living quarters. Many pithouses included an antechamber, containing storage bins or pits.