She is somewhat sedentary but she is cold all the time. Lately outdoor temps are 100 degrees and I have indoor temp set on 83, and she complains if the air conditioner turns on and she feels a breeze. Ceiling fans are a no-no! She stays covered with a throw most of the time and uses electric mattress pad at night! I sweat all day long (and night) and have to go to basement to cool off! I mentioned it to my doctor and he laughed and said, when I go in the nursing home it is like a suana....all the nurses are sweating! What do others do for relief? She will not change
You may just want to try bundling her up more, so you don't have to be sweating in your own house, as that's really not fair to you, when she can just put on more layers. Good luck and stay cool!
Also, since you mentioned she is showing more symptoms "every day"... dementia doesn't really work that fast so I'd take her to the Urgent Care and have her checked for a UTI. If she has a fever, she may be having the chills from it. Elderly women get a lot of UTIs and often don't have physical symptoms except ones that mimic dementia (confusion, personality and behavior changes, delusions). These changes are usually described as "sudden". People with dementia are less able to express what they are feeling so don't depend on her to tell you accurately what's going on with her body. Antibiotics will clear up an infection. If left untreated it can turn into sepsis, which can be life-threatening to someone her age.
My Husband also wore a coat and often gloves and said he felt cold.
Fleece type pull on pants and tops will help make her feel warmer.
Putting a hat on will also make her feel warmer (a lot of heat is lost from the head)
I'm with her about fans! I hate air blowing on me. But I do have ceiling fans but I run the so they direct air up so I do not have the air blowing on me. It still circulated the air I figure that is the important thing. There are fans with no blades so it does not look like a fan (rather expensive but it it helps it might be worth it for you)
You also might want to think about switching to another bedroom if there is one. You can adjust the temperature so it is more to your liking. A window AC unit and that can be your retreat so you don't have to go to the basement.