I am with Vcartier on this one as I have mainly seen weather and temperature have an effect on acoustics. As long as your guitar is in its case it should be fine. And if you are traveling say from extreme cold to a warm place just leave it in the case for an hour before taking it out as it will gradualy adjust to the temperature and the most you will have to do is re tune .

Keep in mind an air conditioner pulls humidity out of the air. This can be catastrophic to an acoustic guitar, and also affect your electrics to a lesser degree. Go to Walmart and get a humidity gauge for you room. They cost abot 10.00 and are well worth it to make sure your room is not too humid or too dry for guitars. Ideal humidity is 45-55%. If it is constantly too dry in there move them. Keep them in the case when not in use.

xD
Haha, yeah, it hasn't been too hot of a summer for us, here in New Jersey.

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"If it's planned, it's boring." - Freddie Mercury

And thanks for all the enormous amount of help, guys! It's very much appreciated.

The A.C. isn't on too much at all; only at night when I go to bed, and even then I put it on 4 or 6, depending on how hot it is. I think my guitars should be alright, thanks to the knowledge you've all provided me with, but I really need to get a humidifier for my acoustic....

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"If it's planned, it's boring." - Freddie Mercury