Reddit reviews D’Addario Acoustic Guitar Humidifier – Releases Moisture Slowly and Evenly – Protects Instrument from Humidity Without Damaging the Finish – Non-Drip String Suspension Design –Easy to Use and Maintain

Keeping it in the case when not in use is very wise. You might want to look into guitar humidifiers. These are small and inexpensive gadgets that help keep the wood from getting too dry or too damp, either of which can be bad, in the long run. I don't think it really matters much which you get.

Edit to add: I have the Planet Waves humidifier that's kept my best instrument safe through the mountains and the deserts.

You are so welcome.

It's not particularly expensive and your guitars will probably fare a lot better for it. you can either humidify them in their cases with something like this, or humidify the room you keep them in. They should really be kept around 40%-55% humidity to keep the wood from cracking, the frets from poking out the sides of the finger board, or in a worse case, the bridge popping off.

It would probably be better than nothing. I think a sound hole humidifier would make more sense in a soft bag. Only thing with those is make sure they have good reviews, since they sit in the sound hole of your guitar a leak would really suck.

http://www.amazon.com/Planet-Waves-Acoustic-Guitar-Humidifier/dp/B0002D0COE/ref=sr_1_1?s=musical-instruments&ie=UTF8&qid=1418155460&sr=1-1&keywords=planet+waves+humidifier

If it's a cash grab it really isn't a very good one. You can literally spend about $0.05 to take a ziploc bag, poke a few holes in it, and put a wet sponge in the bag and leave it in your guitar case. The most popular humidifier (please call it a humidifier, because when you said moisturizer I pictured you rubbing skin moisturizer all over your guitar...) is only $8 on Amazon.

I'm assuming this is an acoustic guitar. If it's electric don't worry about the humidifier. With acoustics you need to put it up in the case and put a guitar humidifier in with it. During the winter when you are heating your house is when your acoustic guitars are most vulnerable to drying out.

Humidifiers are not expensive though they require some attention (refilling).

Here is a cheap one that will work fine.

These require less attention. I use these with my Martin. These are pretty simple and don't require you to mess with refilling.

The damage you describe is probably beyond getting the moisture right in your wood and like I said before get it to a guitar tech soon.

If your guitar was exposed all winter and never had a humidifier the wood could have dried out and the tension from the strings could have caused problems. I did see someone mention that maybe your guitar was designed for nylon strings, if that is the case using metal strings could easily be the cause.

From the sound of it your looking at some repairs that could either be major or very simple; but, a skilled guitar technician needs to look at this thing. This sort of thing will likely get worse and the amount of repair and money needed to fix it will significantly increase the longer you wait.

Considering A/C is typically a dehumidifier, especially in an A/C controlled environment.

EDIT: /u/freelandford means you should have a humidifier for your guitar, not a dehumidifier.

http://www.amazon.com/Planet-Waves-Acoustic-Guitar-Humidifier/dp/B0002D0COE

Am I able to use this guitar humidifier on my classical guitar? The product specifically advertises its use should be for acoustic guitars.

If you keep them in cases when not in use, you can get a humidifier and hydrometer to accurately measure humidity. I just have an empty old spice deodorant casing with half a sponge inside of it that I re-damp every few weeks and stick it in my case. It may not be the most accurate, but some humidifiers are literally the same exact thing. Like this one https://www.amazon.com/Planet-Waves-GH-DAddario-Humidifier/dp/B0002D0COE

I'm pretty sure there are combo units for an actual room. The Guitar Center near me has one in their acoustic room that measures humidity and turns itself on every so often.

I live in the southwest where its incredibly dry. I find myself having to use a guitar humidifier at least once a week. I usually just leave it inside my guitar for about a day at a time. This is what I use.

Really makes quite a difference.

Thanks for the tip are you talking about something like this? It really sucks because all I want to do is play but it seems I'm relegated to power chords only lol.

You can get one like this for each guitar. It will still help in a nylon soft case for sure.

http://www.amazon.com/Planet-Waves-GH-DAddario-Humidifier/dp/B0002D0COE

http://www.amazon.com/Dampit-9128-Guitar-Humidifier-Super/dp/B000AC6DVS