The expression that heat rises never really made sense to me.
I think the reason is that I always lived in a one story house.
I did not truly get that heat rose until I bought my first home that had a loft bedroom. There was just one floor, but you could go up a ladder and be in a little bedroom/loft hidey hole. I thought the little bedroom was super cute and immediately set up my stuff there. It was like a secret bedroom and I liked how it was tucked away in a corner. Well, one winter season changed my opinion. I ran my heater system to the maximum setting. No matter what I did my house felt icy cold. I ended up setting my heater to around 75 degrees in order to feel somewhat warm. Then every night I would sweat buckets in my little high rise bedroom. I could not have a single sheet on me, any clothing and would still sweat to death. Since the bedroom was just a little floor with a mattress on it, I could not hook up a cooling system. I also did not want to run an air conditioner while I had the heater going. It was horrible sleeping up there. I finally had to give up my little hidden bedroom. I removed that loft, upper floor and just made the house one story. This way when the heat rose, the whole house felt the same to me. Ideally, having the heat not rise would be best. But, I am just happy that I no longer sweat buckets at night.