Ductless Vs. Central Air
Central air conditioning systems are easy to operate, unobtrusive and quiet. However, some homes and buildings are not well suited for central air conditioning. This is often due to the costs and complexity of installing a duct system. After World War II, Mitsubishi Electric paved the way for the introduction of ductless systems to accommodate Japan's growing population of high-rise apartment dwellers. Today, ductless systems provide cooling solutions for people in homes, high rises and commercial structures in the U.S. and all over the world.
In addition to eliminating the need for a duct system, ductless air conditioning is also a cooling system alternative for homes and businesses that use radiant heat, a hydronic water heating system or space heaters. Ductless systems (also called "mini-split systems") use an indoor air-handling unit and an outdoor compressor unit. However, unlike a central air unit, which cools the entire house, the air-handling unit disburses cool air into the room where it is located. This means the air where the air handler is located will be cooler than other rooms in a home, which is similar to how a "window-box," or room air conditioner, operates. However, a ductless unit is much more powerful and efficient at delivering cool air.
Central air conditioners utilize a network of ducts to distribute cool air. As the air circulates it becomes warmer and recirculates back through the air handler to the outdoor compressor unit to be cooled again, and the process repeats. Most residential central air systems utilize a "split" system that incorporates an outdoor compressor and condenser. A central air conditioner is one component of an overall HVAC (heating, ventilation, air conditioning) system. The main distinction between a ductless system and a central air conditioning system is that the cool air is delivered through a network of ducts.
Ductless systems have the capacity to cool one room or an entire zone of a home or building efficiently. And, like a central air conditioning system, they are connected to a thermostat so the user can set a precise temperature, versus limiting choices to high, medium and low -- as is the case with a "window-box" or room air conditioner. You can also connect as many as four ductless units to one outdoor condenser unit, and still control the temperate for each unit individually. On the other hand, with central air conditioning you get to combine both heating and cooling needs into one system. Cool air is quietly and efficiently delivered through vents located in floors, along baseboards, on walls or ceilings.
The initial investment in a ductless system can run around $1,000 for the unit, according to Consumer Search.com, as of July 2011. Installation costs are separate. Central systems start at around $2,500 for the equipment only -- the costs for ducts and installation are separate and are based on the size and requirements for the home or building.