I usually wind up having my feet extend past the edge of the mattress while sleeping . My core stays warm but the feet are left out of the warmth of the bed .
I am looking into the wool socks on Amazon . While there I noticed some battery powered heated socks as well .
Not just any "wool socks." You're after Ullfrotte.
https://woolpowerus.com/ullfrotte-original/
Wool is the only fabric known to mankind that keeps you warm even when wet; and if your feet or body sweats, you're wet. Ullfrotte is a blend of wool and synthetic fibers that is soft and comfortable, stretches, lasts a long time, keeps you warm when wet, is breathable, traps body odor (won't stink after wearing for 3 nights in a row), is machine washable in hot water, etc.
I have made my living for the last 27 years working outdoor contract construction from Michigan to New Orleans. In cold weather, all cotton and synthetics (underarmour and the like) do is suck the heat out of you, then get wet with sweat, stink to high heaven and make you colder. Ever heard of the Iditarod?
http://iditarod.com/
I'm not sure if Ullfrotte's website has been updated or not, but they USED to say on their website that every single competitor from every country in the world (in the Iditarod) wears Ullfrotte as undergarments. It comes in 3 different fabric weights; light, middle, and Heavy AKA 200 gr/cm2, 400 gr/cm2 and 600 gr/m2. Each weight is designed, cut and tailored to go OVER each other. You can wear the 400 over the 200 and the 600 over the 400. This stuff is worn by Canadian loggers, the Swedish Military, Mountain climbers in the Himalayas, Offshore oil workers in the North Sea, Scientists working at the North and South poles...Men who make their living in the roughest environmental conditions on the face of the earth depend on Ullfrotte.
I only have the 200 and 400 gr garments. I'm not going to the Himalayas or the Arctic circle.
I own several hundred dollars worth of these garments. Yes, they're a bit pricey. Yes, generally speaking, you get what you pay for. I would challenge any cold skeptic to purchase one or two pairs of their socks from Amazon https://www.amazon.com/s/ref=nb_sb_ss_i_4_9?url=search-alias%3Daps&field-keywords=woolpower+socks&sprefix=woolpower%2Caps%2C335&crid=39HPMVHO6EAVI (Ullfrotte is sold in the US under the trade name Woolpower). Wear them for a few weeks, wash them in hot water, throw them in the dryer, they won't shrink...Make up your own mind. I have several pairs of socks that are close to 10 years old, they wear very well. I use silk liner socks under them, and a cheap Walmart windbreaker as an outer layer on top over them (as a jacket) and I usually wear some cheap jogging pants to cut wind, boots of your choice, and you're set for any weather on the North American Continent.