We have an HVAC system here at work that is unifunctional. Either you can get heat, or you can get air conditioning. And there's some magical switch that a repair man has to manually flip in order to change from one to the other. Luckily, he made that switch yesterday. It's warming up fast, and even though I think it's too early to have the air conditioning on, I am taking full advantage of it. I turned off the heat at home last night, and it was still 67 degrees in the house when I got up this morning. I don't think I turned on the central air at home until July last year.
Of course, when I really need central air in July and August, I don't have it. I live in a furnished, rented house in a resort town, and the folks who own the house only use it during July and August. So in early-mid July, I pack up my personal possessions and move to a furnished efficiency apartment in the attic of a local B&B. Where I have a window unit air conditioner, NOT central air. But I can't complain too much - I also have use of the pool and am excused from yard work for the rest of the summer. Except that the owners don't do so much by way of yard work either, which means the lawn is trashed by the time I move back in and I have to work my ass off to repair it. I think I've convinced them that a sprinkler system is necessary and if so, then things won't look so bad come September.