So the trick with boot gloves is to warm your boots before you put them on, then the boot glove helps the boot retain heat. If you go inside take off the boot glove, remove all the snow crusted on before it melts and let it and your boots warm and dry a little before putting it back on and going out. The longer you ski in a boot glove, the less effective it is as I find it attracts snow and ice build up over time. Once the boot glove is essentially frozen it may actually be a negative vs a positive IMHO. Bottom line is it helps but only for a short period of time, that said my first day skiing in Big Sky this past year in -25, I had boot gloves and no boot heaters and I believe this is what helped me ski a full day and avoid frostbite on my tows. That said my feet super cold and numb by the end of the day and I rushed out and bought some pre-charged boot heaters at Lone Mountain Sports, did the same thing for my eldest daughter who could barely walk as her feet were so cold. Boot heaters saved that trip and let us ski bell to bell during that Arctic freeze. I will note that everyone else in my family made do with boot gloves, though they did not ski bell to bell that trip.