A Hooray For High-Velocity Air Conditioners

Chill out. Even if you have an older home, you don't have to resign yourself to living without the comforts of central air-conditioning. A new technology called high-velocity air-conditioning can be added to almost any home-even those without existing ductwork.
How It Works
Also known as "mini-duct" systems, high-velocity air-conditioning typically uses an outdoor compressor to cool the air, combined with a high-pressure blower (usually mounted in the attic).
Instead of bulky metal ductwork, this technology, developed by SpacePak, uses flexible tubing only two inches in diameter. The insulated tubes can be threaded behind walls or inside closets without damaging sheetrock or plaster. This makes the system much quieter than air-conditioning through traditional metal ductwork.
A mini-duct system also dehumidifies the air more effectively. The high-pressure blower compresses the air and allows it to be in contact with the cooling coils longer-which reduces the temperature and removes more humidity.
It's All Central
Actually, "high-velocity" and mini-duct" systems are just different names for the same type of super-efficient and comfortable central air-conditioning systems. These systems are very quiet, distribute the cool air evenly throughout your house and dehumidify very effectively.
The words "high velocity" and "pressure" may make you think these systems are noisy. Actually, you can barely hear them running and there is no air flow sound at the tiny outlets.
In two-story houses, the mini-ducts are run down from the attic through the corners of the closets or inside walls to the first floor. In a single-story house, the entire system is located in the attic with outlets in the ceiling below.
SpacePak's mini-duct systems use ordinary, high-efficiency, outdoor air-conditioning compressor units. With this mini-duct system, cool air blows out from tiny two-inch openings in the ceiling or high on the walls. You can barely notice the outlets when they are painted the same color as the room. For a decorative look, natural wood outlets are available.