I did 2.5hrs yesterday between 23°F and 30° with just my electric socks set to medium in Northwave Arctic Celsius boots, and it was perfect.
What I like best is the ease of use; pull on socks and slip on shoes, that’s it. No fussing with shoe covers or hoping I picked the right weight socks. If my feet get cold, I can easily reach down to mid-calf and click a button to turn up the heat, and if they’re sweating, it’s another click to drop to low power, or two clicks back to medium power.
I highly recommend winter cyclists get a pair and simplify their lives.
I have these, and while currently unavailable, you can see the elements of a good electric sock and find similar:
https://www.amazon.com/Electric-Rech...pd_rd_wg=uwCXx