A PTAC heat pump is the heating unit in a PTAC Air Conditioner. They are commonly used in North America in hotel rooms, apartments, and small buildings.
What is a PTAC Heat Pump, and What are they Used For?
Typically PTAC heat pumps are mounted on an outer wall or window, and they have a ventilation option that brings in outside air. Each PTAC heat pump is controlled individually. In some parts of the world, a PTAC heat pump is known as a window air conditioner, but it is not the same as the window air conditioner commonly used in North America.
Standard PTAC heat pumps measure 42 x 16 x 13.75 inches, which makes them easy to replace without having to make structural adjustments to the room or building in which they are located. Cooling capacity ranges from about 7,000 to 15,000 BTUH.
A PTAC heat pump has an evaporator coil facing the space to be cooled or heated, and a condenser coil mounted to face the outside. Usually, PTACs have a two or three-speed fan for the inside of the room.
The heating cycle on a PTAC heat pump uses a four-way valve to reverse the flow of refrigerant, and some come with an auxiliary heater for supplementary heat when the temperature dips really low in the winter.
Older PTAC heat pumps have mechanical controls and mechanical push buttons for operation and fan control with a rotary knob to select the temperature. But because electronic controls have developed to the point that they are more cost effective, newer PTAC heat pumps incorporate electronic touch pads and even remote control devices. Newer units usually have energy saving features such as “sleep” modes and other economizing functions so that the temperature adjusts according to the amount of time that has elapsed.
Choosing the capacity of a PTAC heat pump is fairly simple. The rule of thumb is that the larger the square footage of a room, the larger the BTUH of the unit should be. AirConditioningSystems.com recommends the following combinations of square footage and required BTUH for sufficient cooling and heating:
- 100-150 sq. ft.: 5,000 BTUH
- 300-350 sq. ft.: 8,000 BTUH
- 450-550 sq. ft.: 12,000 BTUH
- 700-1,000 sq. ft: 18,000 BTUH
- 1,000-1,400 sq. ft: 24,000 BTUH
Note that these are not the only sizes of PTAC heat pumps. There are several sizes in between, but this should give you an idea of BTUH versus the size of the room.
With PTAC heat pumps, drain piping isn’t required. Any condensate water taken out of the air by the evaporator coil is drawn onto the condenser coil surface by the condenser fan. Once there, the water evaporates.
There are several benefits to PTAC heat pumps. For one thing, these self-contained systems can quickly remove moisture and heat from indoor air once the thermostat is set. It is easy to select fan speed yourself, or you can use an automated fan setting. The same basic settings (thermostat and fan speed) are used when heating is required.
PTAC heat pumps are easy to install due to their standard dimensions regardless of the cooling or heating load requirements. And since both heating and cooling systems exist in a single unit, the installation is simpler than if a split unit were installed.
Additionally, unlike split systems that condition entire buildings through a system of ductwork, a PTAC heat pump only heats or cools the room in which it is installed. Therefore, with multiple systems (as in a hotel, dormitory, or apartment complex) it’s easy to control indoor temperature on a customized, room by room basis.
Modern PTAC heat pumps are also energy efficient and quiet, with EER ratings of between 11 and 12, which is more efficient than a typical North American window unit air conditioner. Also, airflow patterns are designed to reduce the amount of energy consumed by the fan. An efficient PTAC system can result in operating savings in less than one year’s use.
For heating applications the refrigerant runs in the reverse direction from cooling operation. The air outside is cooled, giving up heat to the refrigerant in the pump. The heat is pumped back inside, often rendering on the order of 3 BTUs of heat for every BTU of energy consumed. Many systems have the option of unit-mounted temperature limiters, allowing guests or residents to adjust the in-room temperature settings within a specified range.
PTACs are quieter than ever today, with acoustically insulated bulkheads, acoustical rubber isolators under the compressor, and isolated fan motors. Modern PTAC heat pumps are uniquely well-suited for use in apartments, dormitories, offices, hotels, and institutional homes.