When it comes to heated insoles, ThermaCELL is definitely the brand that most people know. We tried out a pair a few years ago, and while we generally liked them, we were disappointed that they couldn't fit inside a pair of cycling shoes. Well, perhaps we might have better luck with the new +Winter insoles. Just 2 mm thick at the front and 6 at the heel, they're claimed to be the thinnest heated insoles on the market.
One of the reasons that they're so thin (and also water-resistant) lies in the fact that unlike the ThermaCELLs, they have neither a power switch nor a charging port. Instead, they're juiced up wirelessly using an included charging pad, and are activated by an iOS/Android app on the user's smartphone.
That app is also used to control the temperature that's reached inside the shoe, which ranges from 20 to 40º C (68 to 104º F). Thermostats in the toe and heel of each insole automatically turn off the front-located heating element when the target temperature is reached, then reactivate it as needed.
Should the user not have a smartphone on hand, accelerometers in the insoles will still power them up once the wearer starts moving.
One three-hour charge of each insole is said to be good for up to five hours of use. It should be noted that they can only be charged one at a time, however, so the charging time is effectively more like six hours. Additionally, it's worth knowing that the accelerometers will turn off the heating elements if no movement is detected in over five minutes – not a huge deal, but it does mean that users performing sedentary activities will have to periodically shuffle their feet in order to keep the heat coming.
Designed in Switzerland and manufactured in Italy, +Winter insoles have already been available in Europe since last December. Their makers have now taken to Kickstarter to raise funds to increase production and get certification for sales in the US. A pledge of 99 Swiss francs (about US$97) will get you a pair, when and if the financial goal is met.
Prospective buyers might also want to check out the smartphone-controlled Digitsole heated insoles, which additionally have a performance-tracking feature. Priced at €199 (US$210), however, they are more expensive.