My last installment covered several innovations in the area of sustainability. I glossed over Energy Management Systems (EMSs), promising to return to them later, as I am doing today. Along with EMS I also include systems known as Guest Room Management Systems, which add guest controls to a basic EMS; I’ll use the term EMS here to refer to both. While EMS has not exactly been a hotbed of innovation in recent years, it is nevertheless an area where innovation is having a profound impact on how solutions need to be evaluated and selected, whether for new builds or retrofits.
What’s not in question is that these technologies – which can include thermostats, occupancy detectors, keycard switches, networked door locks, light switches, door and window open detectors, bedside and wall-mounted control panels, and integration of information from property management systems (PMSs) and real-time location services – can save a lot of money. Benchmarked studies by vendors show that the best solutions can generate 25-30% energy savings vs. a simple thermostat (in the range of $125 per room per year at typical electrical costs). Many believe that evolving Internet of Things (IoT) technologies have the potential to save even more.
Of course, vendor studies are often conducted under ideal conditions, on new installations and with the vendor constantly monitoring performance and tweaking. There is evidence that savings may drop off substantially if the system is not properly maintained and monitored. Further, some studies have shown that hotels are not particularly good at doing this. This doesn’t mean that hotels shouldn’t still consider these systems, but rather that they need evaluate this aspect when selecting a system and try to find one that they are confident they (or a third party) can maintain and monitor effectively – and include the costs of doing so in ROI calculations. I’ll cover some of these issues today.
EMS systems tailored for hospitality have numerous important features not found in thermostats designed for homes, or EMSs made for office buildings and other structures. Vendors I’ve looked at who claim at least some specialization in hospitality space EMS or GRMS include AuVerte, CIRQ+, Control4, Crestron, Enseo, Evolve Controls, Honeywell (INNCOM), Interel, Legrand, Lutron, Minxon, Schneider Electric, Telkonet, VDA, Verdant, and WiSuite.
First, let’s review the known approaches to managing guest room energy use. Most of them are in use today in products available from vendors like the ones I mentioned. A few have been hypothesized and, in some cases, tested or piloted, but not yet introduced into the marketplace. I’ve included a few that I think have good promise, because you should be talking with vendors about them to see if they’re on their product roadmaps.
The largest source of energy savings for most hotels is through thermostat setbacks, done when the guest room is unoccupied. Typically, the setpoint is raised (in cooling season) or lowered (in heating season) by about 5 degrees Fahrenheit (2 degrees Celsius) when the room is believed by the system to be unoccupied. Lights and some powered appliances may also be shut off. But please don’t make the all-too-common mistake of powering down the outlet that is recharging my PC while I am out!
A key differentiator is how the system detects occupancy. Occupancy detectors alone generate only small savings, and can cause comfort problems for the guest if, due to the guest’s location in the room or the lack of motion of a sound sleeper, they decide the room is empty when it is not. It can be quite disconcerting if you need a nighttime bathroom visit, but it turns out to be longer than the time-out interval, and all the lights go out (hotel bathrooms at night can be very, very dark!). Similarly, keycard switches are often ineffective because guests override them using a spare key (or, with most switches, any stiff card that’s the right size).
This problem can be substantially reduced by connecting an occupancy detector to the door lock (and this is a minimum brand standard for some major brands). In most rooms, a guest can’t leave without opening the door, so if motion is detected while the door is closed, the system can assume that the room is occupied until it is next opened – even if the occupancy detector says otherwise. Similarly, if no motion is detected for a reasonable interval after the door was last opened (typically maybe 10 minutes), then the system can reliably assume that the guest has left and can safely do a setback.
Refinements to this approach include distinguishing whether the door has been opened by the guest or by a staff member – information the door lock can provide to the EMS. Staff may enter the guest’s room 2-4 times per day when the guest is away, for housekeeping and room inspection in most hotels, for minibar or turndown service in some. If the timeout is 10 minutes, this can save 20-40 minutes of heating or cooling cost every day the room is occupied. With a PMS interface, the system can be notified when guests check in and out. Even without a door lock connection to the EMS, knowing that the room is not checked in can override occupancy detectors so that staff don’t trigger heating or cooling. Many systems also enable a larger setback for rooms that are checked out, vs. checked in but unoccupied, a source of additional savings.
Some vendors have been evaluating additional refinements, using real-time location services or even the use of a guest’s keycard in the elevator to alert the system that the guest is about to return to the room. This can allow a slightly greater setback (or make it less likely that the guest will notice the existing setback). Most guests are not sensitive to a 4-5 degree (Fahrenheit) setback as long as, when they re-enter the room, they can hear the heating or cooling fan running. But this means that activating the fan before they open the door is critical; otherwise they may feel the need to adjust the thermostat set point up or down, at which point it will call for additional cooling or heating until the guest decides it’s gotten too cold or hot and adjusts the set point back.
An important point of difference among solutions is the networking protocol. While some older designs use infrared (IR) connections (for example between the thermostat or occupancy detector and the door sensor), most systems today use ZigBee or Z-Wave mesh networks, and a few newer ones use Bluetooth or IP (mostly now Wi-Fi) networks to communicate among devices in the room (notably Interel and Telkonet). Both mesh and IP networks have distinct advantages and disadvantages, and most devices built for the home use some variation of mesh (a reason why most hotel EMSs do as well). For hotels, however, a point of consideration is that while security management protocols and resources are (hopefully!) in place to manage existing hotel IP networks, these are often forgotten when it comes to hotel mesh networks, which may be used for the single purpose of supporting an EMS.
There has been much discussion about IoT security in hotels, and this is an important consideration as IoT devices start to become commonplace within the guest room. ZigBee, Z-Wave and Bluetooth protocols are reasonably secure if properly managed. However, the proliferation of home IoT devices running on ZigBee or Z-Wave means a larger community of hackers attacking them. This leads to a greater need for hotels to ensure that security updates are made, and proper procedures followed, for example when adding a device to the network.
A white paper published by ZigBee member NXP, which manufactures most of the RFID chips used in hotel keys, offers a useful glimpse into some of the complexities of ZigBee security. If you read this and similar documents, you will quickly realize that most hotel engineering and IT departments will not have the skills or knowledge maintain mesh network security. Management of vendors using mesh networks can also be tricky; the software stacks for mesh networking protocols are updated over time to fix security issues, but these need to be incorporated into the products and some may require upgrades to devices already installed in hotels. Hotels should realistically determine how they can manage mesh network security over time – with specialized corporate IT staff, contractors, contractual requirements with vendors, and/or third-party services. Third-party security overlays for RF networks, such as offered by LevL in the automotive market, may at some future date offer hotels options that reduce exposure to bad actors attacking IoT devices. LevL uses radio frequency fingerprinting to securely identify mesh network devices and thereby greatly reduce the risk of spoofing and relaying (which can be easy to do if a device was configured less than perfectly). LevL is currently focused on the automotive market, where its technology can thwart increasingly common “relay” car thefts. But technologies like this could be very useful in any IoT application that has significant security risks, such as hotels.
With both IP and mesh networks, it is critical to monitor the health and network visibility of the various devices. A device that goes offline or is misconfigured will not produce energy savings and may even produce a drain; this can continue for days, weeks, months, even years if not detected by a guest or inspection. Some EMS providers will monitor devices as part of a service contract, or the hotel can do this itself – but again, the question of skill sets and resources can be important. Hotel or corporate staff or a contracted Network Operations Center (NOC) will generally have the resources to monitor and diagnose IP devices, but may require specialized training or skills for mesh networks. Meaningful alerts to local staff need to be sent when anomalies are detected that require onsite remediation.
In addition to monitoring device health and connectivity, it is important that EMSs monitor that results are consistent with settings. A thermostat that keeps calling for heating or cooling for extended periods of time may be an indication of a fan coil unit that needs repair or replacement. A good network monitoring system and dashboard will not only highlight significant issues but can help prioritize preventive maintenance or replacements. For example, a hotel may decide to replace 30 fan coils each year to spread the cost over several years. Instead of just selecting two floors each year, good reporting would allow them to prioritize the rooms with units that are performing the poorest, yielding better guest comfort and more energy savings with the same cost. The more data a reporting system can collect, correlate, and report, the more intelligently the system will work.
In evaluating monitoring systems, hotels should consider the ability and willingness of hotel staff to proactively review performance and address issues. Because many hotels have found this difficult to manage effectively with on-site staff and high turnover, some EMSs are starting to build in more intelligence or even to offer proactive management as a service. These approaches can raise alerts to hotel engineering to check specific issues rather than waiting for someone at the hotel to check a dashboard.
Last but not least, it’s critical to verify that system installation meets the manufacturer’s specifications. One new hotel that got a lot of guest complaints about the heating did a test and put networked sensors at several points in multiple rooms, only to discover that the thermostats were reading as much as 10 degrees off. It turned out that whereas the manufacturer had specified a thermal barrier between the thermostat and the wall, the contractor had claimed that wasn’t necessary. Because of the building design, the heating and cooling did not penetrate to the between-the-wall spaces behind the thermostat, and the lack of a thermal barrier led to incorrect readings. Adding a thermal barrier as a retrofit resulted in substantial and immediate savings.
There is no doubt that modern EMSs can save money far in excess of their costs, but hotels should realistically evaluate how they are going to manage a set of technologies that is both complex, and in many cases unfamiliar. Otherwise, the anticipated savings may never be achieved, or may not be sustained.