Is heating the inside of an apartment or house to a comfortable 22oC waste money or is it being frugal considering that

the people living there are in their and have a somewhat fragile health?

I don't understand the question.

What does your statement "the people living there are in their" mean? Did you mean 'the people living there are in there'?
Apt./condos

can get pretty cold inside especially in Jan./Feb.
The cold snaps are ususally short in duration but when it is here, we spare no expense at keeping warm.

in their 70's...

Is "freezing your ass off" being frugal or stupid?

Is heating the inside of an apartment or house to a comfortable 22oC a waste of money, or, is it being wasteful? Considering that the people living there are in their 70's and have a somewhat fragile health.

Oh now it's clear.

I think that for most people here, having a heater handy allows them to turn it on when they feel the coldest. The temperature inside the home varies depending on the time of day and also whether the place has a lot of sunlight. I think older people can tolerate the cold better than younger people but don't be cheap.

Lots to consider. One is humidity. Kunming is dry, but other cities are not. I find 10 degrees in Kunming OK, just put on a jumper, but 10 degrees in Shanghai is starting to get a bit miserable.

I think the key word is comfortable. If the old people are comfortable at that temperature, then that is ok, remembering also that most of the Chinese people I know wear more layers of clothing at any given time of year than I would.

I'd rather freeze to death than have to worry about the temperature being at a comfy 22 all the time. You'd have to sit by the temperature control 24/7 in Kunming during winter.

Head south in January February or wrap up warm.

you have to worry about pneumonia.
and for elderly folks in particular, i think it can be dangerous.
be frugal with other things.