An A-frame cabin is a building with a tall, triangular roof that resembles the capital letter "A." Typically, an A-frame is a two-story or three-story structure with a wide first-floor living area, a smaller second story above the living room, and a tiny top floor that serves as a sleeping loft. The front and back of the cabin generally have large windows that let in natural light. The energy-efficient design of A-frame cabins is perfect for cooler climates where there’s little need for air conditioning, which makes off-grid living possible.