“Preventive maintenance was not done,” said Jones. “When most of the hotels reopened, there were a lot of filter changes, coil cleanings, and belt replacements. Once their units were back online, conversations were ‘What kind of air filter system is available that can kill the virus if it were ever to enter our place?’”

MONITORING: HVAC system monitoring tools and software allow building managers to remotely check and control their indoor environments. (Courtesy of METUS)

Occupancy levels in hotels shifted drastically during the pandemic. Some managers chose to lower their energy and operating costs by shutting down HVAC systems, which Dennis Cobb, senior director, business development, Mitsubishi Electric Trane HVAC US (METUS) said has the potential to lead to performance issues and poor indoor air quality. However, the national interest in indoor air quality has led many building managers and occupants to care more about their indoor environments and, therefore, their HVAC systems. Preventive maintenance has started to get done again, and there is greater monitoring of humidity, along with monitoring other factors that impact the environment.

According to Damon Smith, associate director, sales – hospitality, commercial HVAC, Carrier, the most widely adopted modification has been improving the central air systems and HVAC filtration to MERV-13. Hospitality brands consulted the ASHRAE Position Document on Infectious Aerosols for guidance.

“Building public trust in healthy, secure spaces without consistent patronage or revenue has been an incredible task, especially as these solutions require heavy investment in technology and new practices,” said Rosa Leal, senior manager, product management – commercial a/c, Rheem. She added that the public needs to feel confident in a facility’s ability to keep them safe.

HVAC Technology For Hotels

The HVAC industry offers numerous technologies for commercial buildings, including but not limited to hotels, to keep their occupants safe. Dedicated outdoor air systems (DOAS) have grown in interest to building managers as they look to increase ventilation demands in their indoor spaces. Certain systems can handle up to 100% outside air without compromising the temperature or humidity level of the areas they service.

“Furthermore, properly ventilated air is essential for tenant wellness and safety, as opposed to a luxury or added benefit,” said Cobb. “Well-designed ventilation solutions provide a healthy and comfortable environment for hotel guests by diluting indoor pollutants and improving humidity control for comfort and mold growth mitigation.”

Conditioning large volumes of outside air can take a lot of energy, so commercial buildings like hotels may also utilize energy recovery technology such as plate heat exchangers or heat recovery wheels. Some businesses also take advantage of sanitizing agents, using portable air cleaners for rooms such as meeting rooms or banquet halls, plus utilizing portable dehumidifiers. Portable technology could also be the right solution for common areas, such as an on-site restaurant.

“Passive technologies like dedicated outside air systems, dehumidification, and high-efficiency filters can all minimize the risk of microbial growth and the spread of pathogens,” said Leal. “More intensive technologies include the use of ultraviolet lighting or bipolar ionization to eliminate microbes or pathogens.”

Other solutions include HVAC system monitoring tools and software, which allow building managers to remotely check and control their indoor environments. This can help them ensure their systems are well-maintained and alert the managers of any potential system issues. This saves labor, allowing that time and money to be put toward larger issues.

“To promote healthy indoor environments, real-time monitoring for a variety of pollutants and IAQ parameters including (but not limited to) carbon monoxide, ozone, volatile organic compounds, formaldehyde and other aldehydes, temperature, humidity, noise, and light are recommended,” said Smith.

Cobb said that diverse VRF systems (such as include horizontal-ducted models, multi-position air handlers, ceiling cassettes, wall-mounted units, and floor-mounted units) can help with comfort challenges.

“Additionally, having an indoor unit in each hotel room can circumvent unnecessary air exchanges between guest rooms and create customized comfort,” said Cobb.

Service and Maintenance for Hospitality

Richard Boothman, director of North American sales at Modine, explained that attention to hotel filtration systems is critical. Some units have a built-in dirty filter pressure switch that will trigger an alarm warning if the filter needs to be changed. For those that don’t have such a switch, monthly checks are recommended. Units, especially ones that condition outside air, generate large amounts of condensate, so technicians should regularly clean the condensate tray, tap, and drain pipe to ensure no blockages occur.

“Periodically inspect the refrigeration coils for signs of corrosion and leaks,” said Boothman. “Should the coil surface need cleaning, do not use cleaning solutions that are corrosive or can cause damage to copper tube/aluminum fin or all aluminum coils. Clean the coil from the leaving-air side so that foreign material is washed out rather than pushed further in.”

Any areas devoted to furnaces should be free of dust, dirt, and grease, and power exhauster discharge and combustion air inlet louvers should be left unobstructed. Technicians should also perform a visual examination of gas lines and piping, condensate trays and drain piping, and manifold orifices, cleaning out the orifices if needed.

In addition to this, if a unit has an energy recovery exhaust assembly, technicians should examine the tension of the energy recovery wheel drive belt for cleanliness, using a vacuum and brush for cleaning.

The wheel-to-housing seals and exhaust blower belt drive should be checked for wear.

“Straightforward preventive maintenance and housekeeping will keep an investment in good working order for many years,” said Boothman.

Neglecting maintenance can lead to a drop in system performance and lifespan. Cobb recommends that hotel managers continue running air conditioning systems to keep rooms dry and free from moisture buildup between visits. This protects both the HVAC equipment and the property, so maintenance should continue even during times of intermittent occupancy.

EMR’s Jones recommends having ductwork cleaned, as well as installing or retrofitting UV technology into a building’s HVAC system.

“UV systems do need maintenance also,” said Jones. “Bulbs and ballast go weak over time. Air ducts cleaned correctly will also improve efficiency.”

Carrier’s Smith explained that portable air cleaners require regular filter changes, but the systems are fairly simple to service and maintain. IAQ monitoring software will require that the data is analyzed for insights.

The most effective place for UV-C lights and lamps, he said, was inside of the ductwork or an air handling unit, and depending on the application, accessing the light could be difficult. Proper placement of UV-C on air handler units can also reduce biofilm growth on and around the evaporator coil.

“There is no single solution for creating and sustaining healthier hotel environments,” said Smith. “A layered defense approach, implementing various levels of control strategies, should be considered to reduce risk and maximize benefits.”