The temperature in the room is not personal. It’s a compromise. Air conditioners blow the same on everybody, though not everybody is comfortable at the same temperature. Soon enough you’ve waged a thermostat war against your coworkers, sobbing and shivering into your sweater as you wonder how humanity sunk so low.
What if you had your own personal thermostat? In September 2017, Embr Labs pitched the good public on a product that could do just that. The Wave, which looks like an Apple Watch worn on the inside of the wrist, promised to regulate the wearer’s temperature. A button turns it hotter or colder, and when it heats up or cools, your inner wrist you feel as if you turned on a personal thermostat only for you. The Wave exceeded its Kickstarter funding goal more than six-fold. It launched to backers in 2018 and later went on sale to the rest of the public for $299.
The Embr Wave’s development began five years ago in an over-air-conditioned laboratory at MIT. It was June, and engineering students Matt Smith, Sam Shames, and David Cohen-Tanugi grew sick of having to wear sweatshirts in order not to freeze. “We found this incredible body of work by researchers at the Center for the Built Environment at the University of California, Berkeley that had already […] conducted the fundamental research showing how local sensations can improve personal comfort,” says Smith.
Using the UC Berkeley team’s research as a starting point, the three engineers built a prototype Wave that summer. They tested it on friends, family, and strangers, who came back with unanimous feedback: The gadget made them feel noticeably warmer or cooler.
After WIRED covered the prototype in 2013, Smith says the team received thousands of e-mails from people asking when they’d be able to buy one. “As first-time entrepreneurs, we were pretty naive about how challenging it is to bring an innovative product to market,” Smith says. It took five years to build a larger team, set up a supply chain, work through problems of sourcing the right battery and cable harness, and bring the Wave from prototype to production. And then there was explaining how it works.
The Wave doesn’t change your core temperature. It’s all about perception. Think of warming your hands over a fire on a cold day. You know you’re not doing much to actually heat up your body, but it makes you feel disproportionately warm all over. That’s because in cold conditions, the local temperature of your hands and feet dictate how comfortable you feel, says Dr. Hui Zhang, a research scientist at UC Berkeley’s Center of the Build Environment. It was her research the Embr Labs’ founders discovered back in 2013 and which inspired the Wave prototype. If your hands or feet are cold, your whole body will feel cold, so Zhang says warming them up first is the fastest way to feel warm. In warm conditions, cooling the head is the most effective spot, but it would be awkward to mount a device there. The next-best spot for cooling: the wrist.
Zhang’s preexisting research in mapping the entire body’s sensitivity to heat and cooling pinpointed the wrist as having a high density of temperature-sensitive nerve endings, called thermoreceptors, that are highly responsive to any temperature change. Smith says that the Wave is designed to be worn on the inner wrist, but some people wear it on the outside of their wrist like a watch and it still works.
As the Wave neared launch in 2018, Zhang’s team studied its effectiveness (funded by the National Science Foundation and not Embr Labs, she says). Her existing thermal comfort models had already shown that localized applications of heat and cooling can cause a person to perceive a whole-body temperature change, but she and her research team expected the Wave would be too small to make more of an effect on the test subjects. The results surprised them.
The Wave has seven temperature levels, and Zhang’s experiment used the more moderates levels three and five. After three minutes of cooling, testers averaged feeling 5.8 degrees cooler; after three minutes of heating, they averaged feeling 4.6 degrees warmer. “It’s very sudden, and pretty strong,” she recalls of using the Wave herself.
Women typically prefer temperatures five degrees Fahrenheit warmer than men, according to a 2015 report by the Dutch Maastricht University Medical Center. Women tend to be smaller than men and have a higher surface-area-to-body-volume ratio, says Zhang, and that causes them to lose heat faster. It’s why women often say workplace thermostats are set for men, leaving them shivering even in the middle of summer. You could pack a sweater, but who wants to carry one around when it’s 90 degrees outside? And a sweater doesn’t fix cold hands or cold feet. On the flip side, if you’re too warm your options get even more limited. There’s only so much clothing you can remove before you become unemployed.
The Wave seeks to solve this. It’s small, hangs on your wrist where you can’t lose it, and works to protect you from both your over-air-conditioned office and your roasting-hot car. Sure, you could save $300 by holding a hand warmer or an ice pack in your palm, but those are easy to lose and no good when you need to type at a keyboard or serve customers behind a retail counter. That’s the price of adopting an early technology, and the Wave is—at least for the near future—the only game in town.