I am someone who turns on the air-conditioner when it gets too hot or too cold, and turn it off when the temperature is fine even if the air-conditioner is not making any noise (meaning it is maintaining the temperature instead of working hard to moderate it to whichever temperature you set).
Many people have said that leaving the air-conditioner running constantly helps you save more than if you keep turning it on and off. I understand the logic, because having to alter the temperature is more intensive than having to maintain it. However, it largely depends on how often you turn the air-conditioner on and off as well, isn’t it?
I don’t turn it on and off that often, so I don’t see how leaving it on can save me more money. And recently, my belief was proven.
Y, the girl who recently left our company, stays very near me. I can get to her place in under 5 minutes by bicycle, which takes care of the doubt on whether our bills are charged differently. Her apartment also belongs to the company and is about as old as the one I am staying at. Y is someone who leaves her air-conditioner on the whole day, except during the time she takes a shower and after (which is about 2-3 hours at most) so that she doesn’t catch a cold coming out to a cold room after her bath. So her air-conditioner is on for over 20 hours a day during the summer.
I asked her how much electricity bill she pays for electricity during seasons she doesn’t use the air-conditioner vs the summer where she leaves it running for most of the day. She said on usual months, she pays about 4,000 yen, and during the summer, it goes up to over 7,000 yen. For me, regardless of the month, my electric bill almost never exceeds 4,000 yen, which means we use about the same amount of electricity during the seasons where we do not use the air-conditioner.
So, during the summer when Y leaves the air-conditioner on most of the day her bill goes up by 3,000 yen while my bill remains under 4,000 (with probably a difference of just a few hundred yen).
Of course, do take note that this is due to the lack of frequency in between each time I turn it off and then turn in back on again. Also, the absolute numbers depends largely on where you live and what company you use as well.