Adoption of smart wearable devices by consumers has gained considerable traction over recent years and it appears this will increase into the foreseeable future. In the first quarter of 2016, shipment volumes of smart wearable devices increased over 65% over 2015. There are a wide variety of smart wearable devices available on the consumer market like smart watches, fitness bands and smart apparel. They can record your heart rate, body fat composition, perspiration, health, body temperature and muscle activity all by touching your skin and can also measure movement, distance and speed using GPS, accelerometers and gyroscopes. The question for the Building Automation and Controls industry is whether this data can be used as feedback to make buildings run more effectively and operate HVAC equipment more efficiently, and if so, how would one go about using this data for that purpose? Can smart wearable data be used effectively to provide more comfortable conditions for building occupants?

To answer these questions, let’s consider what symptoms identify and determine physical, physiological and psychological stress, which is what usually leads to complaints of discomfort by occupants. Stress is normally based in intellect, consciousness and subjectivity that originates from within our nervous system at a subconscious level. This could be in the form of constriction of the blood vessels, constriction of the pupils, muscle tension etc. which are indicators of physical, physiological or psychological stress [1] such as headaches, overheating, irritation etc. Variation of surface temperature of the skin is also an indication of human thermal comfort. Depending how hot or cold a space is, thermal receptors in the skin along with the nervous and endocrine systems will all be receptive to the surrounding environment along with the individual’s perception. The hand, in particular, is probably the most active body part in responding to the body’s thermo-regulation requirements. In warm conditions, the hand is fully vasodilated and the fingertips are the warmest areas of the hand. In cooler conditions, constriction of the hand blood vessels causes the skin temperature of the hand to vary by almost 8°C (14°F) [2].

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Theoretically, the presence of stress combined with the variation in skin temperature of the hand could be used as feedback to Building Automation Systems to augment the control of HVAC systems, although perception of the environment is different for everyone. This is a reminder that thermal comfort is very subjective. The complexity of determining all of the above indicators with reasonable certainty is difficult to say the least. Although some combination of heart rate, skin temperature and muscle activity may give a sign of uneasiness or discomfort, identifying perception is not something that can be accurately detected by devices currently in the market. There are health sensors in the market that can identify stress but they aren’t very accurate. Stress detection is perhaps the most wanted feature on smart wearable devices, so it is very likely that improvements will be made in stress sensing devices in the future. However, despite the availability of a variety of all the features on current consumer smart wearable devices, there isn’t yet enough data that is relevant to HVAC control. In addition, although adoption of smart wearable devices amongst consumers is impressive, wide-scale adoption is still far away. In the US, it is estimated that around 21% of adults own a smart wearable with adoption higher among Generation Y and Z and lower among the older generations. If we assume a similar percentage of building occupants owning and using smart wearable devices, it could be argued that they may not accurately represent the physical and/or physiological state of the entire building population.

Notwithstanding the above, there is also the elephant in the room of data privacy. First and foremost, would people ever allow the automated systems of their building (and thereby property management) to have access to such private and sensitive health data? If so, how would anyone assess if the property management firm has the appropriate security apparatus to ensure this data isn’t vulnerable to hackers and theft? Could property management utilize geo-fencing to isolate the relevant data needed for BAS control? These are just a few of questions out of the many that come to mind when we think about privacy and data gathered by smart wearable devices.

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At this point in time it seems safe to conclude that BAS designers and engineers will not be using smart wearable device data to influence HVAC system control anytime soon, although the possibility certainly exists. With the emergence of new and more sophisticated sensors and the evolution of data security and privacy laws in the future, there may come a time when thermal comfort within buildings can be optimized using smart wearable device data.

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[1] "Introduction to Residential IEQ", Robert Bean, ASHRAE Journal, September 2016

[2] "The Skin's Role in Human Thermoregulation and Comfort", E. Arens and H. Zhang, University of California, 2006

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