– The Backcountry Ski Site
  • Avalanches
  • Gear Reviews
    • Ski Reviews
    • Boot Reviews
    • Binding Reviews
    • Snowboard Splitboard
    • Book Reviews
    • Avalanche Beacon Reviews
    • Airbag Backpacks
    • Backcountry Electronics
    • Misc Gear Reviews
  • Podcast
  • Tips & Tricks
    • Ski Touring Basics
    • Boot Fitting
    • Fitness & Health
    • Gear Mods
  • Trip Reports
    • Fourteeners
    • Huts – Cabins – Lodges
    • Denali McKinley
    • 8,000 Meter Skiing
  • Stories
    • History
    • Humor
    • Land Use Issues
    • Evergreen Ski Touring
    • Poetry
  • Resources
    • All Posts Listed
    • 100 Recent Comments
    • Backcountry Skiing & Ski Touring Webcams
    • Ski Weights Comparison
    • Archives of WildSnow.com
    • Authors Page
    • Ski Touring Bindings
      • Trab TR2 Index and FAQ
      • Salomon Guardian & Tracker
      • Naxo Backcountry Skiing Bindings – Info Index
      • Silvretta Pure Backcountry Skiing Bindings – Info Index
      • Marker F10-12 Duke Baron
      • G3 Onyx Ski Binding FAQ
      • G3 ION Ski Touring Binding
      • Fritschi Backcountry Skiing Bindings – Info Index
      • Fritschi Diamir Frame Bindings Mount DIY
      • Fritschi Diamir Bindings FAQ
      • Fritschi Tecton FAQ
      • Atomic Salomon Backland MTN
      • Dynafit Tri-Step Binding 2001-2003
      • Naxo randonnee alpine touring AT ski binding FAQ
      • Dynafit Skiing Bindings – Info Index
      • Dynafit Binding Frequently Asked Questions FAQ
      • Dynafit Beast 16 FAQ Review 1
      • Dynafit Beast 16 FAQ Page Two
    • History
      • Ski Touring Binding Museum
      • Trooper Traverse Intro & Index
      • Randonnee Ski Touring “AT” ski gear — What is Hip?
      • Chronology
    • Backcountry Skiing Core Glossary
    • Gear Review Policy & Disclosures

– The Backcountry Ski Site

  • Avalanches
  • Gear Reviews
    • Ski Reviews
    • Boot Reviews
    • Binding Reviews
    • Snowboard Splitboard
    • Book Reviews
    • Avalanche Beacon Reviews
    • Airbag Backpacks
    • Backcountry Electronics
    • Misc Gear Reviews
  • Podcast
  • Tips & Tricks
    • Ski Touring Basics
    • Boot Fitting
    • Fitness & Health
    • Gear Mods
  • Trip Reports
    • Fourteeners
    • Huts – Cabins – Lodges
    • Denali McKinley
    • 8,000 Meter Skiing
  • Stories
    • History
    • Humor
    • Land Use Issues
    • Evergreen Ski Touring
    • Poetry
  • Resources
    • All Posts Listed
    • 100 Recent Comments
    • Backcountry Skiing & Ski Touring Webcams
    • Ski Weights Comparison
    • Archives of WildSnow.com
    • Authors Page
    • Ski Touring Bindings
      • Trab TR2 Index and FAQ
      • Salomon Guardian & Tracker
      • Naxo Backcountry Skiing Bindings – Info Index
      • Silvretta Pure Backcountry Skiing Bindings – Info Index
      • Marker F10-12 Duke Baron
      • G3 Onyx Ski Binding FAQ
      • G3 ION Ski Touring Binding
      • Fritschi Backcountry Skiing Bindings – Info Index
      • Fritschi Diamir Frame Bindings Mount DIY
      • Fritschi Diamir Bindings FAQ
      • Fritschi Tecton FAQ
      • Atomic Salomon Backland MTN
      • Dynafit Tri-Step Binding 2001-2003
      • Naxo randonnee alpine touring AT ski binding FAQ
      • Dynafit Skiing Bindings – Info Index
      • Dynafit Binding Frequently Asked Questions FAQ
      • Dynafit Beast 16 FAQ Review 1
      • Dynafit Beast 16 FAQ Page Two
    • History
      • Ski Touring Binding Museum
      • Trooper Traverse Intro & Index
      • Randonnee Ski Touring “AT” ski gear — What is Hip?
      • Chronology
    • Backcountry Skiing Core Glossary
    • Gear Review Policy & Disclosures
   

Thermacell Proflex Heated Insoles in AT Boots — Review

by Lou Dawson March 18, 2015
written by Lou Dawson March 18, 2015
Thermacell Proflex insoles with batteries removed, red remote control.

Thermacell Proflex insoles with batteries removed, red remote control.

I know these guys who like the crisp air on 8,000 meter peaks. They bring skis sometimes too. But their feet get cold. Last winter one of those characters (Mike Marolt) told me his etail business would be selling Thermacell heated boot insoles, and that they “saved my feet and I couldn’t climb without them.” Sure, he sells the things but Mike is a straight shooter so I figured the insoles would be worth a test. Mike was right, they really do work. A few trade offs, but they’re lightweight, compact, and don’t suffer from the wire failure you can get with boot heaters with an external battery pack.

Battery inserts to connect to the red connector which appears to be a  sealed 'weatherpack' type connector.

Battery inserts to connect to the red connector which appears to be a sealed ‘weatherpack’ type connector. Nonetheless we’d recommend a dab of dielectric grease.

We field tested the Thermacell in a variety of situations. WildSnow blogger Joe Risi used them in his tight and cold Dynafit ski boots during a long day of skimo race support here in Colorado, while Lisa and I’ve had them in both ski boots and work boots. They don’t produce what we’d call a huge amount of heat (they can’t, as the battery is small and you need it to last). Yet installed and used properly, you get a noticable warmup (they say “100 degrees”) and around four hours of on time at the medium setting, depending on age and temperature of batteries.

Four hours may not sound like much time, yet by turning the insoles on only when needed you can extend the benefits out to a full day. (The on/off switch is a small remote control you can hang from a pack strap or tie to a string in your pocket. If you do want to max out, a set of spare batteries weighs 1.9 ounces, (54 gr), small, they’ll fit in any pocket or take nearly zero room in your repair kit (caveat on battery swapping, see below).


Charger is USB.

Charger is USB.

In my view, Thermacell Proflex work best when used in a boot that’s already optimized for warmth. If a boot is too tight and thin in the toes and forefoot, thus cold, you’ll have to leave the heaters on continuously and you’ll run down the batteries. That’s assuming you’re out for more than a few hours. A quick tour or ride on the chairlift? Just invoke the electrons and enjoy.

Field swapping Proflex batteries is doable but problematic. You have to take your boot off, reach inside, and pull a tiny ledge on the battery with your fingertip. This can’t be done with gloves, and could even be tricky with cold hands as you have to get it just right and pop the battery out. Inserting fresh batteries is easier yet could still be too fiddly in a desperate situation. (What someone should do is make a ski boot with this system molded into the liner, with an exterior accessible battery compartment on the liner cuff. Heaven.)

Swapping the battery is not glove friendly.

Swapping the battery is not glove friendly. We’d recommend Thermacell would include a better grab tab on the batteries. The situation is exacerbated when your boot liner squeezes the flexible insole and presses against the sides of the battery.

The batteries lose 2% charge per hour when inserted and set to “No Heat,” which is actually a sleep mode. When removed from the insole they’re truly “off” and probably lose very little power in a practical sense, though you’d want to recharge after extended storage.


Moisture intrusion and corrosion of the battery connector could be a concern, so I’d recommend a dab of dielectric grease on the connectors. Boot fitting could be an issue, as the Proflex insole adds 13.4 millimeters under your heel and 6.8 mm under your forefoot. Thus you’re dealing with added ramp (<> 6.6 mm) as well as stack. (note that thickness varies with exact measurement points, as nearly the whole insole is tapered in thickness from heel to toe.)

Depending on foot volume and boot geometry, the added thickness may be acceptable — or it could be a deal breaker. At the least, you’ll want to jerk out your existing footbeds and heat-mold your liners with the Proflex. Beyond that, find a boot with adequate volume and a customizable boot board, and do more extensive mods. I just happened to have the perfect boot for that purpose, a Scott Cosmos 2 with the classic “Garmont” last and a removable boot board. Follow along.

Cosmos 2 and a highly moldable Intuition Luxury Liner.

Cosmos 2 and a highly moldable Intuition Luxury Liner. Due to the thickness of the Proflex insole I wanted something with a highly compressible area under the foot.

Insole length can be customized a bit.

Insole length can be customized a bit.

Scott Cosmos lends itself to this kind of customization due to having a removable boot board.

Scott Cosmos lends itself to this kind of customization due to having a removable boot board. I cut the front part of the boot board off to allow max volume. The heel pad was trimmed down so it matched level with the exposed boot bottom, and re-installed. Overall this increased the boot volume to perfectly accommodate the thick Proflex, as well as compensating somewhat for added thickness under the heel which (undesirably in many cases) increases interior boot ramp angle.

Trimming the boot shell heel pad.

Trimming the boot shell heel pad.

Exact added weight of the Proflex is hard to figure, as you’ll probably get rid of some boot board as well as chucking your normal footbed (stock or otherwise). As a rule of thumb, if you strip out some parts figure you’ll add about two ounces per boot. Weight of one stock Thermacell, with battery, is 3 ounces (size small). That’s a small price to pay for feet being safe and snug, but is quite a bit of lug as a percentage in a superlight boot. What Thermacell should do is make replacement lightweight insoles without batteries, that the user can swap in when they don’t need footwarmers. That way you’d get your hard earned (and sometimes costly) custom fit when you don’t need the warmers and want the least mass.


Get a set to begin customizing for next winter, or perhaps you’ll still be skiing for a few more months and want the warmest feet?Shop for em!

Lou Dawson

WildSnow.com publisher emeritus and founder Lou (Louis Dawson) has a 50+ years career in climbing, backcountry skiing and ski mountaineering. He was the first person in history to ski down all 54 Colorado 14,000-foot peaks, has authored numerous books about about backcountry skiing, and has skied from the summit of Denali in Alaska, North America’s highest mountain.

www.loudawson.com
0
Email
previous post
Karakoram Snowboard Products, Extended Industry Visit
next post
The God of Skiing — Book Review

Trip Reports

  • A Small Hut for Big Skiing in the San Juans: Aladdin’s Lamp

    April 23, 2024
  • Revisiting a 2011 Trip Report: Adventure in the Pickets — Thread of Ice Ski Descent

    December 9, 2022

Avalanche Department

  • Ask a Forecaster: Q&A with CAIC’s Andrew McWilliams

    March 10, 2024

Tips & Tricks

  • Transition Efficiencies 101 with Tech Binding Heel Units

    January 6, 2023
  • Visualizing the Backcountry as a Splitboarder: Minimizing the Challenges of Movement by Anticipating Terrain

    December 5, 2022
  • TURBOCHARGE YOUR TRAILHEAD BEACON CHECK

    November 15, 2022

Recent Comments

  • Daniel on Backcountry Ski Boots Buyer’s Guide: The Touring Boots Worth the Money
  • Jim Milstein on Best Touring Packs for Guides and Daytrippers
  • Bergen Tjossem on Much more than a steep ski: Fischer Transalp 92 CTI Long-Term Review
  • Maciej on Much more than a steep ski: Fischer Transalp 92 CTI Long-Term Review


  • Facebook
  • Twitter
  • Instagram
  • About Lou Dawson
  • Terms of Service
  • Authors Page
  • About
  • Contact
  • Advertise
  • Copyright & Legal
  • Website Security

@2025 - All Rights Reserved. Designed and Developed by WildSnow


Back To Top

Read alsox

Wolverine Split Sticks: A Terrific Telescopic...

January 2, 2025

Backcountry Ski Boots Buyer’s Guide: The...

November 27, 2024

The Best Scarpa Maestrale RS Yet...

October 31, 2024