The smokers I built have had insulated boxes. I borrowed a cooker for a comp after I sold mine and the box wasn't insulated. I vowed at that time to NEVER own another cooker without an insulated box. I was used to mine and we fought that think all day and night. I built another rig and the temp control on it is almost like a uds, just add a split once an hour and it doesn't move. I'm fixing to build a backyard model with an insulated box an am curious how little wood it will use.
Its Si-intistic, Jack!
One lovely UDS
Shanaynay--Custom Home Built Smoker on Wheels