The world's first Passive Annual Heat Storage home was built in the winter of 1980-81. Through its first summer, the specially insulated earth around it extracted the summer heat from the home keeping it a cool 65 degrees F. on the lower floor and 74 on the second floor ceiling at the dome's zenith.

The following winter it coasted along supplying its heating needs by conduction back into the home. Gradually cooling off, and in spite of a cold Montana, by April it had not dropped below 66 degrees F.

For the first time in history, a cold-climate building had taken care of 100% of its cooling and heating needs through out an entire year! It did this without the aid of either furnace or air conditioner. It simply used its unique layout of building materials to control heat naturally on an annual basis.

The dome's unique shape was chosen because of its great strength being capable of supporting a load of earth over 4 feet thick. The Passive Annual Heat Storage (PAHS) method, however, does not require the use of a dome, but can be used with any earth sheltered shape.

As with its annual cycle of heat absorption into the earth around the home during the summer, or more precisely, whenever the internal temperature attempts to rise, at sun set (shown here,) heat flows automatically, without equipment, to maintain a comfortable temperature throughout the night.

Note: The dome is a private residence, and is not the headquarters of the Rocky Mountain Research Center.

Still, the most advanced book available on the subject is "Passive Annual Heat Storage, Improving the Design of Earth Shelters." This 1983 text is still quite up to date as it teaches the basic methods of understanding natural heat flow methods that never change. Other supplementary materials, home plans and instruction videos are available.

You can order books, videos, and papers on a large variety of topics which are available from the
Rocky Mountain Research Center.