If you must

I wouldn't recommend, but if you must drop a heavy air conditioning unit from a third-story window, do so on a day when there are three feet of snow below said window. It won't save the AC unit, but it will save your older brother from having to pick up lots of little pieces of AC. On the other hand, don't do it to your parents AC while they're in Europe, or they are likely to revoke staying-in-Mom-and-Dad's-room priveleges on future occasions.

If you have any questions regarding the strategy, tactics, ethics, or mechanics of dropping AC units out of windows, just call 1-800-555-DUMB, and ask for my sister Polly.