PTACs - Split Ductless Systems By Betty Stephens
PTAC (packaged terminal systems) are also known as wall-split air conditioning systems or ductless systems. These PTAC systems which are frequently used in hotels have two separate units, the evaporative unit on the interior and the condensing unit on the exterior, with tubing passing through the wall and connecting them. This minimizes the interior system footprint and allows each room to be adjusted independently. The terminal package is the condensing unit located on the exterior and includes the compressor, condenser and condenser fan. The other terminal package is the evaporative unit located on the interior and handles air cooling and distribution. The internal evaporative unit includes the fan, expansion valve and evaporator coil.
PTAC system may be adapted to provide heating in cold weather, either directly by using an electric strip, gas or other heater, or by reversing the refrigerant flow to heat the interior and draw heat from the exterior air, converting the air conditioner into a heat pump.
While room air conditioning provides maximum flexibility, when used to cool many rooms at a time it is generally more expensive than central air conditioning. The primary disadvantage of ductless air conditioners is their cost. Such systems cost about $1,500 to $2,000 per ton of cooling capacity. This is about 30% more than central systems and may cost more than twice as much as window units of similar capacity.
An additional possible disadvantage that may increase net cost is that ductless systems may sometimes not be eligible for energy efficiency rebates offered by many electric utility companies as part of an incentive program to reduce summer cooling load on the electrical grid.
Ductless systems offer much higher efficiency (up to 27.1 SEER on some systems). Today's brands include Aircon, Carrier, Daikin, Klimaire, LG, Mitsubishi, Sanyo, Fujitsu and YMGI.
Most ductless (split system) air conditioners still typically provide cooling to a single room or interior zone, just like a window air conditioner or PTAC; but more powerful outside units are becoming more and more available, supporting cooling of ever-more interior zones. Advantages of the ductless system include smaller size and flexibility for zoning or heating and cooling individual rooms. Flexible exterior hoses lead from the outside unit to the interior one(s); these are often enclosed with metal to look like common drainpipes from the roof. Those enclosures can be painted to match the color of the house.
If your goal is to create a quiet, comfort controlled room, or simply want to heat or cool an area without expensive ductwork, the ductless systems set a new standard for efficiency, great looks and comfort.