An A-Frame house is a steep-sided house, triangular in shape, popular for its ease (and low cost) of construction, and in cold climates, for its steeply peaked roof which sheds snow easily. They tend to be one and one half or two and one half stories tall (think attic space), and have more than the usual number of windows in them. Because their sloping roof tends to go all the way to the ground, they generally have a signifcant amount of their volume wasted, though that will add to the insulative properties of the building.
The first A-Frame was built in 1957 by architect Andrew Geller in Long Island, New York. After being featured in the New York Times, it rapidly gained international acceptance. While they do have a certain amount of wasted space, it is generally cheaper to put up an A-Frame with a significant amount of loft/attic space than to put up a single story house with traditionally framed construction, and as such has long been a popular house design for first-time builders.
The design of the A-Frame house was doubtless inspired by the A-Frame tent, which design has been in use in colder climates for centuries. A-frame tents generally have rigid stands at the ends, and a rigid cross-member across the top peaked part of the tent, and are then draped with a canopy of some sort, having no floor. Because of this design they require staking at all corners, though there are self-contained a-frame tents with an integrated floor. A-Frame tents shed rain and snow easily, but have extremely limited headroom.
References:
- House Styles: A-Frame Style. About.com, 2003.(http://architecture.about.com/library/bl-aframe.htm?terms=a-frame)