Air Conditioning: Cool old houses
The Old House Web
The system uses small-diameter flexible ducts which are threaded between floors, through ceilings and down walls, rather than larger sheet metal ducts that would require major structural carpentry and would alter the appearance of the home. A quiet blower unit, small enough to fit inside an attic, basement, or crawl space, runs the system. For winter warming, the system can be heated through a hydronic (hot water) coil, electric coil, or a heat pump with selected models.