Cshenk wrote:

"Joe" wrote

It takes a certain amount of time to reheat back to your 65 in the morning.
It takes a certain time to drop back to 57 when you cut the heat back.

Unless we know how long those 2 are, no one can answer your question as it
depends on the insulation and heating efficiency of your home.

Nonsense. Any setback saves energy, no matter how short.

This is 300-year-old high-school physics :-)

Nick