I think there is a bit of apples and oranges in this question.
It's not the heat it's the humidity!
If you live in Pasadena California, you can have high 80s temp and below 39% humidity.
In Florida last month we had a day of 80 degrees and 96% humidity.
We generally run at 78* and I bump to 77* if I'm hot.
Years ago I ran a dehumidifier, when I got the humidity under 40*,
I could raise the temp 4* and still feel dry and comfortable.
The problem with the dehumidifier was that it created a lot of heat and where ever
you put it, it got warmer. That and they also recalled my Kenmore dehumidifier because of a fire hazard.
I just came in from outside, it's 96* with 46% humidity, I bumped the thermostat from 78* down
to 77* and the humidity has dropped from 47% to 46%.
I'm comfortable, but I'm wearing shorts and no shirt and the fan is running on high.