Hotel room automation includes a variety of products and applications that can be combined in various ways to suit a business’ specific needs.
Bathroom lighting occupancy sensors
This very simple device is installed in the duplex electrical box that would normally house the bathroom’s light switch (the box must be located in the bathroom). It is similar to other wall-mounted occupancy sensors, except that versions have been developed with integrated night lights specifically for the lodging industry. These industry-specific models also are capable of longer timeout periods—up to one hour—to reduce annoying false-offs (where the sensor inappropriately turns off the lights when an occupant temporarily leaves the room). Further, short timeout periods have not been shown to benefit energy savings; studies show that 75 percent of bathroom lighting energy is consumed when the lights are left on for more than one hour.
Room-based occupancy control
This category includes the widest variety of choices and applications. Both HVAC and lighting can be controlled on a full-room basis because all of the controls they use are local to the room and do not depend on connection to a whole-building automation system. Many of the products we list here are available in a wireless version (for communication to the other products involved), which can lower the cost of installation. (Note that when wireless products are used, they typically must all be from the same manufacturer.)
Digital thermostats with occupied/unoccupied modes. These thermostats differ from other commonly available energy-conserving thermostats in that they switch between the occupied and unoccupied modes based on a device that senses some indication of room occupancy, as opposed to using time-based control. Selecting the correct setback temperature in these devices is very important to minimize guest complaints. If the setback is too deep, the room will be uncomfortable for a long period after arrival of the guest; a small setback may not provide the estimated savings. These thermostats can work with packaged terminal air conditioners (PTACs—typically, the lodging industry uses units that are mounted on the wall of the room) or central cooling systems.
Lighting control. Hotel room lighting control can be easily implemented if all the lights in a room are on one circuit. However, this is typically only economically feasible in new construction. A contactor that switches the power on and off to the room’s overhead lights and to electrical outlets used for lamps can be controlled by the same occupancy sensor used for the thermostat or HVAC unit. Most existing facilities probably do not have the appropriate circuit configuration for room-based lighting control—construction cost pressures dictate that wall outlet circuits cover as many rooms as possible and that overhead lighting will be on different circuits—so it is not as widely applicable as room-based HVAC control.
Devices used to sense occupancy. These can include:
- Passive infrared (PIR) occupancy sensors. These devices sense the heat emitted by an occupant. They are best placed on the ceiling in a location that enables the sensor to detect an occupant’s presence in as much of the room as possible to reduce the possibility of false-offs. A version is available that looks like a smoke detector (Figure 1), purportedly to reduce the chance that an occupant might try to defeat the device. Models that are integrated into the thermostat are also available, though this design may reduce the sensor’s coverage and accuracy.
- Wall-mounted key card switches. These devices, mounted within the room, activate when the room’s door key card is inserted. They are simpler and less expensive than a PIR occupancy sensor and do not have any potential for false-offs. However, occupants can override them by leaving a second room key in the switch, thereby defeating their purpose. Further, the predominantly available switches cannot detect the difference between a room key and any other card of similar size.
- Entry lock switches. These switches are integrated into the entry lock, so they must be compatible with the lock itself. They are also only available with wireless communications (to the thermostat made by the same manufacturer). Therefore, this technology is not as widely available as some of the others. And because it cannot tell whether only one or all of the room’s occupants have left, it is prone to false-offs. In fact, some manufacturers of this technology recommend that entry lock switches be used in addition to a PIR occupancy sensor to improve operation (which will reduce the number of false-offs that either device alone would be prone to).
Due to the size of larger hotels and the presence of more common space, conference rooms, offices, restaurants, etc., these facilities can use general-purpose building automation systems (BASs) to control HVAC and lighting. These systems can be extended into the room to provide the same functions as room-based controls. When a BAS is present, or planned for in new construction, it makes implementation of the following more feasible.
If a BAS is not already present, it would be difficult to cost-justify installing one just for room control. In addition to the cost of installing some room-based components, there would be the costs of the BAS itself, the installation of communications wiring, and the front-desk integration software, the sum of which would likely prove prohibitive to implementing this option.
This approach does not use automation technology, but nevertheless can be a very useful tool for hotel room energy conservation. It involves training the housekeeping staff turn off lights and set the HVAC system to an unoccupied setting. Many hospitality businesses list this technique as one of their energy conservation strategies. Unfortunately, there are no data available concerning its effectiveness versus the automation technology discussed above, and it has the disadvantage of requiring extensive and ongoing training efforts.
