I made the example above because not only does setting the thermostat too cold in summer make it uncomfortably cool, it also wastes a huge amount of energy to achieve that extra cool temperature!
That's fine if you have very deep pockets and don't mind throwing your money away on paying huge energy bills, but most of us don't want to be so wasteful. It makes a lot of sense to only cool the house as much as it needs to be to make it COMFORTABLY COOL!
For me (and I'm sure I'm not alone in this), a comfortable temperature is around 72-74°F and it doesn't matter if it's that level in summer or winter. Think over that.
Would you set the thermostat to 64°F in winter?
Of course you wouldn't! So why set it there in summer? That's what one of my friends had done and then wondered why the AC was icing up and dripping water on the floor!
There's another reason to be sensible with energy consumption. The environment is damaged by energy production, so the less we use , the less needs to be produced and the impact on the environment is less.
That's my common sense opinion and I hope it will be yours too!