1 no How dumb, you are saying cooling it when you are on vacation is
cheaper than not cooling it
2 no Dumb again
2b exact exterior temp , solar load, wind, humidity have been
maintained in a lab or your dumb again
3 no , unless voltage is higher at night, which it often is.
4 Hard water , mineral buildup
6 Question is openended
7 Hacks do a lot of stupid things, just ask Daves Heating or I can
listen to you.