64 degrees is going to be extremely cold for most Americans. At least in the north where I've spent considerable time.

I grew up in a household that would keep it at 60 during the day, and 52 degrees at night in order to save money. I then took on a job that had me doing service calls into people's homes and it was eye opening that even the most poor run down apartment I'd visit would have the heat blasting at 75+. Oftentimes with a window cracked to boot.

I don't think I have a single friend these days that keeps it lower than 70, usually in the 72-74 range. And yes, I find it extremely hot when visiting.