News Treehugger Voices INDEX: Can Wristify Work as a Personal Air Conditioner? By Lloyd Alter Lloyd Alter Facebook Twitter Design Editor University of Toronto Lloyd Alter is Design Editor for Treehugger and teaches Sustainable Design at Ryerson University in Toronto. Learn about our editorial process Updated October 11, 2018 ©. Wristify via INDEX Share Twitter Pinterest Email News Environment Business & Policy Science Animals Home & Design Current Events Treehugger Voices News Archive TreeHugger is covering the INDEX awards, celebrating the idea of "Design to Improve Life". This post covers one of the 46 finalists chosen from 1,123 entries. I am fascinated by the Wristify, a bracelet that makes you feel cool or warm. It is described on its INDEX page: Everybody knows what it’s like to be in a room where half of the occupants are freezing in sweaters, and the other half are sweating in short sleeves. Wristify solves that by individually regulating body temperatures and saving loads of money on energy costs. Wristify/Screen capture They explain how it works on their website: The bracelet provides heating or cooling to the wearer's skin at the press of a button. It isn't designed to affect the temperature of your entire body. Our comfort depends on a lot more than just core temperature, and we have drawn on the last 30 years of thermal comfort research to design a device for maximized comfort that is also discreet and energy-efficient....Studies show that local warmth or cold leads gives you a body-wide sensation of thermal comfort. This is exactly what happens when you dip your toes in the cold water on a hot sunny day at the beach, or when you place a warm washcloth on your forehead on a cold evening. To go totally over the edge on this, Wired titles their story: MIT wristband could make AC obsolete. Now this is a subject dear to my heart at TreeHugger, as I have spent a lot of time trying to understand the issues of comfort recently, as noted in my post Should we be building like Grandma's house or like Passive House? I have been learning from Engineer Robert Bean's amazing website, which teaches that thermal comfort is a state of mind. Like the designers of the Wristify, Bean notes that it's all in your head, in your Hypothalamus to be precise. However he also notes that it is connected to "something like 165,000 (+/- a few thousand) thermal sensors in your skin. For impact consider that the average human has a skin area of approximately 16 ft2 (1.5m2) to 20 ft2 (1.9m2) or about the hood area of a small to mid-size car." The Wristify it trying to fool a very small subset of this giant organ. © Comfort zone chart Victor Olyay Also, Robert Bean, Allison Bailles and Victor Olgyay have all taught that there is a lot more to comfort than just temperature, there are also air speed, mean radiant temperature, humidity, clothing, metabolic rate and more. Yes, the wrist is a sensitive point. But can "sending cooling or warming waves to the thermoreceptors on the surface of the skin"- a limited area of the skin on the wrist- really make a difference? I have been skeptical of INDEX entries before and have been wrong. (Like I was about 2013 winner Freshpaper) And I see all kinds of people in the videos oohing and ahhhing and saying it works. But once again I am skeptical; I hope I am wrong again.