Ductless Air Conditioning & Heating

Ductless Mini-Split Systems

• Ductless mini-split systems eliminate the costs and potential complexities involved in installing ductwork. Shortly after World War II, the Mitsubishi Electric Company introduced ductless mini-split systems to provide cooling and heating for Japan’s growing population of apartment residents. Ductless systems use an indoor air handling unit and an outdoor compressor unit -- the unit is referred to as a “split” system precisely because some of the elements are inside, others outside. The indoor unit looks similar to a window air conditioner, only larger. Heating is accomplished by adding a heat pump or electric heat strip to the indoor condenser.

Packaged Terminal Air Conditioners

• A second ductless alternative for heating and cooling is a packaged terminal air conditioner (also called PTAC). These systems are commonly used in hotels, hospitals, offices and commercial buildings, and are sometimes found in homes. A PTAC does not require an outdoor compressor/condenser unit for cooling; all of the mechanics for heating and cooling are contained within the indoor unit. The average PTAC unit is about 42 inches wide and is installed through a wall. Units have a built-in heat pump to warm a cold room, which reverses operations to deliver cool air in the summer.

Advantages

• Mini-split systems and PTAC units eliminate the expense and need for ductwork. They provide heating and cooling specific to a given room or large space and occupants can control the temperature, therefore controlling energy usage. Mini-split systems are attached to thermometers so you can preset temperatures. PTAC units have manual controls to turn the temperature up or down and to turn the system on and off. Multiple units installed in multiple rooms of the same building can therefore mimic the effect of central heating and cooling.

Disadvantages and Cost Considerations

• Unlike PTAC systems, which work in any climate, mini-split systems work best in locations where the average temperature does not fall below 40 degrees Fahrenheit. Initial costs are a consideration for both types of units, which start at about $1,000, as of publication, for one main unit. This cost is less than installing ductwork and a central heating and cooling system, which can start at $2,500, unless you need several units. Other considerations are largely cosmetic and aesthetic. Both systems involve having a large unit protruding permanently through a wall, versus the unobtrusive look of central heating and air conditioning systems, which only require discreet vents to deliver warm or cool air.