Packaged terminal units are self-contained heating and cooling units installed through an exterior wall, usually under a window. They are the familiar boxes found in hotel rooms, motels, seniors' residences, apartments and some offices. The most common types are the packaged terminal air conditioner (PTAC), typically with electric resistance heat, and the packaged terminal heat pump (PTHP).
These units are inexpensive, simple to replace and give each room its own control. They also have well-known weaknesses: noise, limited efficiency, air leakage through the wall sleeve and, in most cases, no reliable ventilation. In Canadian climates, cold weather performance is an added concern.
Types of packaged terminal units
| Type | Description | Typical heating |
|---|---|---|
| PTAC | Through-wall unit with compressor, coils and fans in one chassis | Electric resistance, sometimes hot water or steam coil |
| PTHP | Same form, with a reversing valve for heat pump operation | Heat pump with electric resistance backup |
| Vertical packaged unit (VPAC or VTAC) | Installed in a closet, connected to an exterior louvre; can serve short ducts to adjacent rooms | Electric, heat pump or hydronic |
| Single packaged vertical unit (SPVU) | Larger vertical unit, often for classrooms or small offices | Electric, heat pump or gas |
All share the same basic layout: an indoor coil and fan facing the room, a compressor and outdoor coil facing the exterior louvre, and a wall sleeve that holds the chassis.
Why hotels use them
- Low first cost per room compared with central systems
- Individual room control, so each guest sets their own temperature
- Simple replacement: a failed chassis can be swapped in minutes, often with a spare kept on site
- No central plant, ductwork or refrigerant piping between rooms
- Room-level energy savings, since unoccupied rooms can be set back or turned off
Limitations
Efficiency
PTAC and PTHP efficiency is limited by their compact size. Minimum efficiencies are set federally and through energy codes. Newer units with variable-speed compressors and improved designs are available, but packaged terminal units generally remain less efficient than VRF, water source heat pump or central systems.
Cold weather performance
Conventional PTHPs typically switch from heat pump operation to electric resistance at an outdoor temperature somewhere around freezing or a few degrees below, depending on the model and settings. In much of Canada, that means a large share of winter heating is electric resistance. Some newer units offer better low-temperature performance, but most through-wall units are not cold climate heat pumps in the sense described in our guide on cold climate heat pumps.
Air leakage and envelope
The wall sleeve and chassis create a large opening in the exterior wall. Poorly sealed sleeves and worn gaskets allow cold air infiltration, drafts and, in some cases, water leakage. Air leakage through PTAC sleeves can be significant at the building scale, increasing heating load and stack effect problems in taller buildings.
Noise
The compressor and fans are in the room. Noise is one of the most common guest complaints. Units with variable-speed compressors and fans are generally quieter.
Ventilation
Many PTACs have an "outdoor air" damper, but the amount of air it delivers is small, uncontrolled and affected by wind. It does not reliably meet ventilation requirements, and in winter the damper is often closed by guests or maintenance staff because of drafts.
Ventilation for hotel rooms
Hotel guest rooms need ventilation under the National Building Code or provincial code, typically through ASHRAE 62.1. Bathroom exhaust also runs continuously or on demand in most hotels. Common ventilation approaches with packaged terminal units include:
- Corridor pressurization: a make-up air unit supplies tempered outdoor air to corridors, and air transfers under guest room doors to replace bathroom exhaust. Simple and common, but transfer through door undercuts conflicts with fire separation, smoke control and acoustic goals, and actual airflow into each room is hard to verify.
- Ducted outdoor air to each room: a dedicated outdoor air system supplies a measured amount of outdoor air directly to each room. This is more reliable and allows energy recovery from bathroom exhaust.
- In-room energy recovery ventilators: small units in each room or suite. These provide balanced ventilation but add maintenance points.
In any approach, the overall building should be balanced so that exhaust and supply airflows are close, and the building is not strongly negative, which draws cold air through PTAC sleeves and windows. See building pressurization and infiltration control.
Controls and energy management
Guest room controls are an important energy measure:
- Occupancy sensing or keycard systems that set back temperature when the room is unoccupied. Our guide on occupancy-based HVAC control discusses options.
- Setpoint limits to prevent extreme settings.
- Networked controls that allow front desk or building automation systems to set rooms back when unsold.
- Heat pump priority: for PTHPs, ensure the unit uses heat pump mode as much as possible and only uses resistance heat when needed.
- Fan mode: continuous fan operation increases noise and energy; auto mode cycles with heating and cooling.
Replacing or upgrading packaged terminal units
When a hotel or apartment building reaches the end of PTAC life, owners face a choice:
| Option | Benefits | Considerations |
|---|---|---|
| Like-for-like replacement | Lowest cost and disruption | Locks in existing performance; check sleeve condition and sizing |
| High-efficiency or variable-speed PTHP | Better efficiency, quieter | Must fit existing sleeves; cold weather performance still limited |
| Vertical packaged units | Quieter, better appearance | Requires closet space and new louvres |
| VRF or water source heat pumps | Better efficiency and comfort | Major renovation; ventilation still needed |
| Add a DOAS | Fixes ventilation and drafts | Requires duct routes and roof space |
Before replacing, inspect wall sleeves for corrosion and leaks, check electrical capacity, and verify that new units match the existing sleeve or that an adapter is available. Many manufacturers use standard sleeve dimensions, but not all.
Maintenance
PTACs need regular attention: filter cleaning, often monthly in hotels; coil cleaning; condensate drainage; gasket and sleeve sealing checks; and periodic deep cleaning to control odours. Outdoor coils face weather, snow and debris, especially on lower floors. Keeping spare chassis on site reduces room downtime.
Frequently asked questions
Do PTACs meet ventilation requirements on their own?
Generally not reliably. The small outdoor air damper on most units is not a substitute for a designed ventilation system. Most code-compliant designs provide ventilation through corridors, ducted outdoor air or in-room ventilators.
Why do PTACs use so much electricity in winter?
Most PTACs use electric resistance heat, and most PTHPs switch to resistance heat near or below freezing. In cold climates, that can mean high electricity use and demand.
Are PTHPs a good electrification choice?
They are better than PTACs with resistance heat, but limited cold weather performance means a large share of heat may still come from resistance elements in much of Canada. Other heat pump systems often perform better.
Key takeaways
- Packaged terminal units provide low-cost, room-by-room heating and cooling in hotels and apartments.
- Most PTACs use electric resistance heat, and most PTHPs switch to resistance near or below freezing.
- Through-wall units do not reliably provide ventilation; corridor, ducted or in-room ventilation is needed.
- Sleeve leakage, noise and limited efficiency are the main drawbacks.
- Combine occupancy-based controls and good maintenance, and verify ventilation and pressure relationships with air balancing.
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