Ryan, try taking out the Accu-Rite, pull the batteries, replace them and then set the unit and it's probe near but not in the enclosure. Get a read on what it says the room is to check if it seems to be reading close to correct.

What substrate are you using? Are you sticking the Acu-Rite way down into the substrate or setting it on top of the substrate? How do you have the unit and it's probe set up?