A:AnswerIt is going to cycle on and off like your AC; but is the door being left open. Or is the room where it is placed very hot. A hot room like a garage with no ventilation will affect it's performance.
A:AnswerNot sure of temperature but I keep mines closer to cold than coldest and it still works well .
I don’t have a garage but I know garages are extremely cold so I would keep it in between the cold and colder