I just had a York package unit delivered and installed today. While the tech was unboxing the unit he said he had some good news, they were giving me a 3 ton unit instead of a 2 1/2 ton as specified in the proposal. Now Im always up for a bargain but I have heard that it is counter-productive to oversize a unit beyond a certain point. My living area is just under 800 sq. ft. with another 250 sq. ft. that I would like to enclose and air condition in the future.My old unit was 26 years old and still working, I replaced it in hopes of saving money on my large electric bill. Is a 3 ton unit going to be effecient and save me money or did I just replace one expensive to run unit with another?