Have a rental property been working on that now vacant. Janitrol 2 ton heat pump about 6 years old.
Noticed I would temp at 84 when I left at night. Following morning I get there and the actaul temp reads 77. Look like a cheap no name thermstat so replaced with a used Honeywell that worked good before. Had stored in my shed because switch to a programable one in my own home.
This seemed to work fine for days. When there working during the day I turn down to about 77 and then back up when I leave to about 84. Then a few times found the place at 77 the next morning. According to the display and verified with a laser therm I have.
Called my AC guy. He saids it has to be the termostat.
So buy a new honeywell thermostat and install. A few days later its doing the same.
Either something wrong my AC guy does not know about. Or at night when I leave its able to hold the 77 temp without the ac cutting on for 12 hours with the thermstat turned up to 84.
It does seem to turn on and off like it should during the day when working there.
Does this make any sense?