A hotel can provide all the amenities it wants but if its interior is too hot or too cold, guests are going to be dissatisfied.
So it’s essential to they take care of heating and cooling systems, ideally having common areas like the lobby and bar at a pleasant temperature for everyone, and giving guests control within their own rooms.
There are several important factors to take into account with heating and cooling systems: Noise, energy-efficiency, maintenance, longevity, air purification and the aesthetics of a unit.
Different Systems to Consider
Because there are a few different types of HVAC systems to consider for hotel common areas and guestrooms, it’s important to understand what they are and their strengths.
PTAC Systems
Most frequently, hotels install Packed Terminal Air Conditioner systems into guestrooms. PTAC systems are self-contained units, installed under windows mostly, and allow guests to control the temperature in the room. And typically, the controls are very simple, often an up and a down arrow, sometimes an icon, said Weejen Lynch, vice president of engineering, McKibbon Hospitality, Tampa, Fla.
PTAC systems certainly have their downside, said Matt Green, president of Brucker Company, a leading Chicago-based HVAC manufacturer’s representative. They’re noisy because the compressor, the loudest part, is directly in the guestroom. They’re also not energy-efficient. But they do have the lowest upfront costs, though at the expense of total lifecycle costs, he said.
They don’t look good either, he said. They’re “a piece of plastic in the room,” and they blow air directly onto the room’s inhabitants, which isn’t very comfortable.
PTAC units are easy to replace and because of this, most hotels have a few in storage, ready to put into use as needed. The old unit simply slides out and the new one is easily installed.
It’s important to size PTAC units correctly to the size of the guestroom, said Tony Abate, chief technology officer, AtmosAir, Fairfield, Conn. “We often think bigger is better but when you oversize an AC unit it cools very quickly, but it doesn’t dehumidify well.” This can lead to mold and mildew, he said.
It’s a good idea to put the thermostat in the center of the room, he added, where it can accurately monitor the temperature away from the window.
Fan Coil Units
In corridors, hotels often use Fan Coil Units (FCUs) that they tend to place at each end of the corridor, which gives individual control to that area while also ventilating the space, said Abate. These FCUs run heated or cooled area through pipes, and that air is dispersed by a fan. They can be controlled from the unit or from a central system. Fan coil units also work well in smaller spaces like a gym or meeting room, because they can give users individual control over the temperature in the room.
Some hotels even put them in guestrooms, in a hatch or even in the ceiling, but generally, said Abate, they’re better for larger rooms and suites, of 400 square feet and above.
VRF Units
VRF units (Variable Refrigerant Flow) adjust the refrigerant volume in a hotel’s system to provide the heating/cooling required with the minimum energy use. They also turn off when a guestroom is empty.
They can go into guestrooms or into hotel general areas, but mostly the latter, said Richard Glatt, sales manager, applied products, Fujitsu General, Pine Brook, N.J. These systems have appeared on the market in the past 20 years and, he said, “are much more energy efficient (using up to 30 percent less energy, according to Hitachi) and quieter, and probably have a longer lifespan.” They are also better at dehumidifying.
But they’re more complicated than PTAC systems, and more expensive, and if they break, the effect is wider ranging. For example, if 20 rooms are handled by one VRF system and the system fails, all of those rooms would have no heating/cooling, whereas if a PTAC system fails, it only affects the room it’s in.
Which system hotel owners install can also depend on how long they plan to own the hotel, said Glatt. If they expect to have it for a long time, a VRF system makes sense because the energy savings are significant.
For the most part, said Glatt, luxury hotels typically install VRF systems since they’re expensive but a better product. “PTACs can be noisy and rattly and don’t do a good job of removing the moisture from the space and can get clammy,” Glatt pointed out. “The VRF removes the moisture much better, is quieter, more energy efficient.”
Another benefit with VRF systems, he said, is that they can share air and heat and cool at the same time. So if a guest in one room is heating their room and a guest in another is cooling it, “it shares the heating and cooling [so] you’re not really creating heating and cooling. You’re taking the heat from where you don’t want it and putting it where you do.”
Another plus is they use a heat pump, which, said Glatt, is more capable and energy-efficient so when it’s cold outside, you can extract heating. But with PTAC, when it’s below 30 degrees outdoors you’re running on electric heat, which is not very efficient.”
VRF is starting to erode the market share for PTAC systems, said Green, especially when hotels take ADA requirements into account. These regulations state that a wheelchair must be able to maneuver around each side of the bed. Without a PTAC unit, there’s more available space in the room so the rooms can be smaller, reducing building costs.
Water Source Heat Pumps
PTACs are starting to be replaced by water sourced heat pumps (WSHP), said Green, especially in mid- to high-rise applications.
WSHP is different from fan coil or VRF (although there are water source VRF systems). A WSHP system uses a condenser water loop to exchange energy/heat between zones and allows each room to operate in heating or cooling independently of other rooms.
One consideration with WSHP, he said, “is that the compressor—aka the noisy component—is located in the occupied space and can result in similar noise complaints to PTAC.”
On the plus side, these don’t need ugly louvers on the outside of the building. And they are a lower cost than fan coil with the same benefits of heating or cooling on demand. “So we see that be the dominant choice in densely populated urban areas,” he said.
Purifying Air
COVID brought us an understanding of air quality and to keep the air pure, the best thing hotels can do is regular maintenance on their heating and cooling units, said Alexander Van Winkle, regional director of engineering, McKibbon Hospitality.
Since COVID, said Abate, hotels let customers know what they’re doing to make sure the air in their hotel is healthy and safe. Coming up, he expects to see sensors guests can see, that report on the quality of the inside air.
Every system needs to bring in outside air, said Abate, and this is then filtered to remove decontaminants. But the amount of outside air you need to bring in can be reduced when you’re cleaning the air through filtration because that cleans the air exceptionally well.
“The requirements are relaxed if you’re showing you’re cleaning the air better than it would be with outside air,” said Abate. “And this creates a big energy saving opportunity—outside air is very expensive because you have to cool it and dehumidify it. This is a way to bring in less humidity and less outside air.”
For this to work well, a hotel needs very good filters and ideally some new technology, he pointed out, like bipolarization or UV systems that can finish cleaning the air.
Another important factor with air purification is it leads to cleaner surfaces, too, said Abate. Now hotels can swab a surface and see if anything microbial is growing on them. “They can communicate [to guests] that this technology is cleaning the air and the surfaces.”
Some, but not many, hotels are adding air purification systems (IAQ monitoring or IAQ improvement technologies) that can be standalone or within the walls and ceilings, and which monitor air quality in real time.
This, Green explained, is an additional upfront cost and an energy and maintenance cost, but it can be a differentiator for hotels “that allows them to market to a customer base that is willing to pay a premium.” Thus, they are largely used in luxury hotels, to date, he said.
However, he said, “there is growing awareness and ongoing education to the marketplace. We are hopeful that the industry will begin to understand the benefits of improved IAQ on hoteliers' ability to differentiate their offerings based on safe IAQ.” Industry standards such as RESET Air, Well Building, FreshAir Certified and LEED are helping in this endeavor.
Maintenance
Performing regular maintenance is the most important thing a hotel can do to ensure its HVAC systems perform well and last a long time.
McKibbon has a computer-generated maintenance schedule that reminds each hotel to tend to the machines on a quarterly basis—cleaning filters, making sure the evaporators work, that the evaporator drains are clear and working properly. And annually the company suggests that each hotel bring in a professional company that can run through the entire system and make sure the amp draws are correct, check pressure of the freons, check the motors. On top of this, housekeepers are encouraged to clean the filters as they clean the rooms.
It's also important to change the filters often since air is moving through them, said Abate. “Unchanged ones make it harder to push the air through and it can damage the unit and can weaken the air flow, which is not good for comfort in the room. Generally it’s on a quarterly basis, but in a dusty location or near a highway, you need to do it more often.”
The annual cleaning should also not be avoided, he said. “Anything that’s processing air has components that will get wet and dirty and can be prone to mold and bacteria. So you might need to slide the PTAC out of its unit and give it a thorough cleaning, especially the coils.”
For VRF systems the maintenance is minimal but it’s important to change and clean the filters on the indoor units, and the indoor coils (monthly or quarterly) and clean the coil on the outdoor unit (annually), said Glatt, but in general these systems are much easier to maintain.
A Fan Coil Unit doesn’t require a lot of maintenance because the only moving part is the fan coil and the valves. But, said Green, you’re shifting that maintenance to a complex center system and that requires a different level of service. A luxury hotel will have an engineer on staff who can handle monthly maintenance, he said, “but as soon as something is wrong they bring someone in.”
Typically these units’ filters should be inspected monthly and hotels should inspect/clean a unit’s drain pan and coils “periodically throughout the cooling season to ensure they are free of debris and to check for any growth of algae/bacteria.”
On top of this, hotels should inspect the electrical components, supply fan blower and thermostat annually to ensure they are clean and operating properly.
When To Upgrade/Replace
As long as an HVAC unit is functional, it’s not likely a hotel is going to replace it. Deciding whether to replace a unit depends largely on age, said Van Winkle. If the costs of repair are likely to exceed 50 percent of what it is going to cost to buy a new unit, he said, “that’s when you consider an upgrade.”
In general, said Lynch, PTAC units last for six or seven years; HVAC systems for 10 to 12 and rooftop units around 20 years. But, said Abate, “those systems can suffer greatly if they’re not maintained.”
This article was originally published in the April/May edition of Hotel Management magazine. Subscribe here.