Welcome Will, that's great that you are getting in to your music! This place is an excellent resource, use it.
Jak is right, there isn't a set time that is required, and I completely agree that efficiency is key. An effective 1 hour practice session is better than 3 hours of messing around. Having said that I just want to make sure that you are enjoying playing the guitar. Have some discipline, and practice the more tedious parts of playing guitar(I'm currently working on theory and sight reading sheet music). But just make sure that you aren't putting in time because you feel like you have to, you should want to play. You should want to practice.
To be honest though, it takes thousands of hours to master anything truly difficult. So even if you don't want to, pick up the guitar each day, tell yourself "I'll just put in 15 minutes right now." And if you really do love it, you will find that even if you weren't feeling it at first, that an hour will have gone by and that you enjoyed it!