Everyone is different as far as what temperature makes them the most comfortable, and comfort with temperature also differs with indoor and outdoor temperatures, for example, someone may be comfortable with 85 degrees outside, but would be super uncomfortable with the same temperature inside, and I asked some friends to see what temperature makes them turn their cooling systems on in the summer, the first friend I asked is Paul.
Paul lives in the south, where it is notoriously warm and humid, even before the Summer months.
Paul said that as soon as it hits 75 degrees, his central air is turned on in his home, and he explained that it is more the humidity than the heat that motivates him to turn on his air conditioning system. Paul does not want his home getting that humid, moldy, uncomfortable feeling. He runs his central air until it cools down in the winter which does not always happen where he lives. I asked my friend Eri, who lives up north, but Eri does not have a central a/c, because it is not necessary where she lives. Instead, she has two window cooling system units- One in the bedroom and one in the kitchen. Eri said that she will usually turn on her window air conditioning system when it gets up to 85 degrees or when it feels humid. It is possible for her to get comfort most of the Summer from windows being open and using a fan, instead of spending money on a/c. It is legitimately interesting how in different parts of the country, people have different opinions on when they feel it is necessary to use their a/c.