Are log homes warm?

It depends on the way that they are assembled. They can't have any gaps for air to leak in or they will be cold. Thicker logs will also have a higher R value.

R-value of wood
The R-value of wood ranges from 0.71 for most hardwoods to 1.41 per inch for most softwoods.

R-value of a log wall
A 6-inch thick log wall has an R-value of just over 8, while a 10-inch milled log wall has an R-value of 10.7.

R-value of a log home
Log homes generally have a 30–40% lower R-value than conventional wood stud walls.

Log homes can be well-insulated if built properly. Here are some ways to improve the energy efficiency of a log home:

Add insulation:
Build an interior wall,
insulate the roof, or add closed cell spray foam
insulation.

Seal and caulk: Use caulking and sealing
materials to prevent air leaks.

Bond logs: Stack and bolt logs every two feet to
prevent shrinkage.

Use the right wood: Use woods like Fir, Pine,
Cedar, and Spruce to prevent shrinkage.

Log homes are common in colder climates like Alaska and Canada, where they are often built without added insulation. However, log homes can be inefficient compared to conventional wood stud walls and may not meet building code energy standards.

And a standard home in the US is made of 2x4s and plywood.

Building a timber farm home that will five times the insulted value of a standard home, and I lived in a 1800's log home with a wood stove that was the warmest home I ever lived in.

The thicker the timber logs the higher your insulation R value as well.

Heck rent a RBNB one yourself in a cold environment and test it yourself maybe you could give the wifey your log while staying there by the fire! Hey!

my sister has a log home; full logs tend to work pretty well as insulation; typically you get ~4 inches of solid wood between inside and out, takes a bit of time and work for thermal change to get through (one of the directives for people lost in a wildfire used to be to get into a log cabin and shelter there; the walls take a good while to ignite). the bigger issue with them tends to be that all the cracks and crevices make for an excellent hiding ground for spiders (and scorpions if you're in the right area)

Don't over build. 500 sq ft is a lot easier to heat than 3000. My grandparents had/have a log cabin. Under 1000 sq ft on 2 floors, only heating is a wood stove. I never spent a cold night there in my life and spent many a winter night there

Cold won't easily pass through the logs (wood); cold which gets into "log cabins" generally comes in through the seams between the logs and doors & windows (like in more conventional structures)

My late Grandfather lived in a log cabin and it was pretty warm in the winter, provided the wood stove was well stoked.

I live in a home that the main part is log home

Then expansion they used a new building technique.

I live in a very old, large timber home (weather board), and it's hard to heat and very expensive.

Oh, heck yeah Canada has cold places in the winter it's called the whole dang county!

Log homes are warm they insulate behind the logs a log cabin is cold