Lets talk about the basics of drywall in your house.
Drywall is your first line of defense in keeping unwanted noise from coming inside. Due to the fact that it’s a solid panel of plaster it gives great reduction to noise and a benefit towards thermal resistance. In most cases drywall between one house from the next will be fairly standard with the chance of thicker drywall being used in which case helps reduce noise even more. Usually however thicker drywall is put up in areas where more privacy is wanted like in an office area or between bathrooms.
The great part of drywall is the noise reduction.
As pointed out in an older post your standard drywall usually has a rating of around 30 STC which is good for stopping noise but could be a lot better. Typically if more noise reduction is wanted the standard drywall which is 1/2″ thick is replaced by a 5/8″ thick drywall. In a few cases this thick drywall can be doubled up but then you have the problem of shrinking your rooms in order to accomplish this, especially if you’re upgrading an existing home. However a lot of people do not know of the possibility of upgrading your house’s drywall to special soundproofing drywall. These types of drywall normally will stay at the 5/8″ thickness but provide significant noise reduction.
The STC rating can almost double which in return in some cases is just like putting up two more layers of noise reduction from just one wall(if not more!). The best of the best which can be up to an STC rating of 80 would make it pretty much impossible for you to hear outside noise through the walls. You could probably be able to put a running lawn mower next to the wall and not hear anything. Perhaps you would hear a very very quiet hum in the background if you listened closely. Imagine never hearing a car on the road while next to a busy intersection or people talking near your house. However these really high end STC rated types of drywall are typically for commercial uses like in hospitals and areas where there is a lot of noise from machinery. Though don’t rule out the lower end version as they can make a world of difference and still be quite affordable.
Costs between different drywall types.
Unfortunately there is no real standard pricing in terms of drywall but the general guideline is something like around $8-10 dollars for a panel. Soundproofing drywall will typically be between 3-4 times that a panel so it is quite the difference in price. But if you want to stop outside noise for good or at least in part of your house that extra expensive will be quite worth it. Always shop around though and get estimates as there’s a good chance you can get a discount between various companies. If you’re a do-it yourselfer, you have even a better chance of saving additional money but it will of course take some time to be properly installed. Installing drywall is something that can’t be rushed as every crack and hole just means less sound reduction and higher heating/cooling costs. Which brings us to the last point that while the costs maybe higher you will save money on heating/cooling costs due to the thickness and special materials used.
Is it worth it for me?
It really depends on how bad of a sound issue you are having. If it’s just a little bit a noise then drywall is probably not the best path to take. Not to mention that if it isn’t a lot a noise your main issue may just be your windows in which case that will probably be typically cheaper to replace/upgrade than an entire room’s drywall. Or just some thick curtains will help resolve the noise. If you’re really unsure though ask around for free estimates and for builders to come out and give you their professional opinions. (Always get a second and third opinion too of course!) Also ask if you could get in contact with any past customers of theirs who had special drywall installed to see their thoughts on if they think it was worth the change.