Hotel and multi-unit residential HVAC

Hotels, condominiums and rental apartment buildings share a defining feature: many small, separately occupied units stacked on top of each other, each with its own occupant expecting individual control. That shapes everything from equipment selection to how odours, noise and smoke move through the building.

The two building types differ in some important ways. Hotel rooms turn over nightly and sit empty much of the time, while apartments are occupied continuously by people who cook, shower and do laundry. But the underlying HVAC problems are similar enough to treat together.

Which codes apply

In Canada, multi-unit residential buildings fall under different parts of the building code depending on size:

• Part 9 (houses and small buildings): buildings of three storeys or less in building height and up to 600 m2 (about 6,460 ft2) in building area. Ventilation follows Section 9.32, which is prescriptive and residential in character.
• Part 3 and Part 6: larger buildings, including most hotels, mid-rise and high-rise apartments. Part 6 requires HVAC systems designed to good engineering practice, with ventilation typically referencing ASHRAE 62.1 for common areas. For dwelling units, codes and designers often refer to ASHRAE 62.2 or CSA F326 for residential ventilation.

Provincial codes in Alberta, BC and Ontario adopt the NBC structure with local amendments, and energy requirements vary considerably. BC's Energy Step Code and Toronto's Green Standard, for example, push residential buildings toward much higher performance than the base code. Confirm specifics with the authority having jurisdiction.

In-suite heating and cooling options

Cooling has moved from optional to expected. Older apartment buildings without cooling are increasingly difficult to rent, and heat waves have prompted several Canadian cities to consider or adopt maximum indoor temperature requirements for rental housing. Retrofitting cooling into existing buildings often uses ductless heat pumps or vertical heat pump units.

For hotel-specific equipment, see packaged terminal units and hotel HVAC. For VRF considerations, including refrigerant concentration limits in small rooms, see VRF systems.

Ventilation strategies

Ventilation in multi-unit buildings has evolved through three broad approaches.

Pressurized corridor systems

The traditional approach in Canadian mid- and high-rise residential buildings supplies heated outdoor air to each corridor from a rooftop make-up air unit. The air is meant to pass under suite entry doors through an undercut, providing ventilation to the suites and keeping cooking odours and smoke from entering the corridor. Bathroom and kitchen exhaust fans in each suite remove the air.

In practice, this rarely works as intended. Stack effect, wind, weatherstripped doors and unbalanced suite exhaust mean that upper floors often get too little air and lower floors too much. Many residents seal their door undercuts against corridor noise and odour, cutting off their only fresh air.

In-suite heat recovery ventilators

Most new multi-unit residential buildings in Canada now provide ventilation directly to each suite with an in-suite heat or energy recovery ventilator. Each suite gets a known quantity of outdoor air, with heat recovered from the exhaust. Corridors receive separate, smaller ventilation, primarily for pressurization and code compliance. See ERVs and HRVs for selection guidance.

In-suite units need wall or roof penetrations for each suite, maintenance access for filter changes, and defrost strategies suitable for Canadian winters. In very cold climates, ERVs with frost control or HRVs with preheat are used to avoid core freezing.

Centralized ventilation with ducted supply

Some buildings use central heat recovery units on the roof with vertical shafts supplying and exhausting each suite. This keeps maintenance out of suites but needs significant shaft space and careful fire and smoke separation where ducts penetrate suite walls.

Compartmentalization and air leakage

Air movement between suites is the source of many complaints: cooking odours, smoke and cannabis odour from neighbours, and noise through penetrations. Stack effect in tall buildings drives air upward through shafts and leaky floors in winter.

Good practice includes sealing suite perimeters as airtight compartments, testing suite airtightness during construction, sealing penetrations around pipes and ducts, and keeping exhaust and supply balanced within each suite. Our guide on building pressurization and infiltration control explains how stack effect affects tall buildings.

Hotel-specific considerations

Hotels have additional requirements:

• Guest room control: occupancy-based setback, often linked to the room key card or door and motion sensors, reduces energy use in unrented and unoccupied rooms.
• Noise: guests expect quiet rooms. Through-wall units and fan coils should be selected for low sound levels, and duct connections to corridors need attention to cross-talk.
• Humidity: in summer, oversized PTACs short cycle and leave rooms clammy. Properly sized equipment and dehumidified ventilation air help.
• Back-of-house: kitchens, laundries, pools and ballrooms each need dedicated systems with their own exhaust and make-up air.

Common problems found during testing

Air balancing and commissioning in residential buildings typically turn up:

1. Bathroom exhaust fans delivering a fraction of rated airflow due to long, crushed or poorly terminated flex duct.
2. Kitchen range hoods discharging into ceiling spaces instead of outdoors.
3. Corridor make-up air units with dampers or heating sections not functioning.
4. In-suite HRVs unbalanced, with supply and exhaust far apart.
5. Dryer exhaust lint buildup creating fire risk.

Air balancing of suite exhaust and in-suite ventilators at turnover resolves many of these before occupants move in.

Key takeaways

• Part 9 or Part 3/Part 6 of the building code applies depending on building size, with significant provincial variation in energy requirements.
• Corridor pressurization alone is an unreliable way to ventilate suites, so new buildings typically use in-suite heat recovery ventilators.
• Cooling is now an expected feature in both new and retrofitted residential buildings.
• Airtight suite compartmentalization reduces odour, smoke and noise transfer between units.
• Hotels need occupancy-based guest room control and particular attention to noise and humidity.
• Testing and balancing of suite exhaust and ventilation at turnover catches the most common deficiencies.