How to make my Power Bills Lower?

Temperatures inside our homes, and energy efficiency 12/29/17.

If we fill a glass with water, the water is heavier than air, and is at the bottom of that glass. This is VERY obvious.

Hot air rises, and cold air falls, which is not so obvious! You may notice your pets getting off the floor in the winter, or onto the floor in summer, going to where they are most comfortable.

There is another consideration, which is just HOW does our forced air HVAC system work, with rising hot air, and falling cold air?