I've been relying on electric heaters since about 2012. Without them my maximum time outside in the winter is 45 minutes to an hour. It is difficult for me to recommend a specific product at the moment. There are numerous heating methods being used. For older types such as the Hotronics heater I started with, the heating element is concentrated in a small spot. Newer products use inexpensive flexible carbon fiber as the heating element which allows a larger area to be heated. The availability of carbon heated gloves seems to have exploded this season with everybody selling them, but it doesn't look like that is the case with heated insoles yet. What I'm using now is semi-DIY from a discontinued product.
This one on Amazon might be decent for the price.
https://www.amazon.com/Thermrup-Elec.../dp/B07K9ZCG78
Pros:
- trim to fit portion (unheated) is all at the rear.
- large heating area.
- 7.4v 2500 mah batteries (more voltage generally means more heat, many products are 5v)
- multiple power settings
Cons:
- battery pack attachment system looks a bit hokey
- heat appears to be concentrated in the middle of foot, outside of foot might get cold, ideally there would be full width coverage around toe area.
- might be on the thick side
Another pro would be the battery packs themselves which could be used for a DIY heat project since the controller is built-in. You could get some cheap heat pads from ebay or aliexpress and plug them straight into the battery pack for a custom solution that puts all the heat at the front of the boot. My current setup uses heat pads similar to
THESE taped to the front of my insoles, but those specific ones don't have the correct connector. The battery pack for the Amazon insoles is probably a
3.5 x 1.35 dc barrel connector.