Well the heat has to go somewhere and thats what the 'outdoor' end of the air conditioner does. Perhaps you might think about using a good ventilation fan to pump air into the grow room. I think your neighbors might be suspicious of an air conditioner running at full blast on a 60 degree day. To kill the smell you can use an activate carbon filter. You can make your own cheaper than buying the overpriced made up ones. The carbon filter and fan should cost much less than the air conditioner unit - and the fan won't use near the electricity as the AC unit.

I pump air out my grow room (single story home) into my back yard - by the time the air hits anyone around me its pretty well dissipated - and at any rate the old fart that lives close has very limited smell since he's had cancer of the nasal passages. I took the liberty of asking him about his sense of smell since I needed to know.

I get temps of 90-100 regularly in the summer so I revert to using fluorescent lights and a smaller grow to keep the heat down. The T5 HO lights work pretty good.