Not sure if you saw the Monster Turkey I posted on Monday, so here are some details:
32+ lbs of Turkey (mistake! Stuffed)
Outside ambient at 3:30 PM 37-38 F
1 hour later 35 F
2 hours later 33 F
5 hours later 29 F ( I had a small thermometer that said it was actually colder buy I'm going by a guys weather station a couple of blocks away.)
• MES location outside under roof eve, in 8' high brick wall backyard (we are backed up to a major street), so very little wind chill.
• 40" MES (1.5 years old no-port window).
• Set temp 270 F,
• Max temp achieved according to the MES controller readout, 198 F.
• After 1 hour remote internal probe said inside MES temp was 230, and eventually remained steady 240-250.
• Every 30 minutes I checked the MES Controller temp, two Taylor remote temps (one in bird, one at base of bird in middle of cabinet), plus the outdoor ambient. The red light was ALWAYS on.
• I pulled the turkey at 140 deg and finished in the oven.
Conclusion: My MES struggled due to the cold outdoor ambient and never achieved the desired set point 270 deg, this was due to both the outdoor ambient and possibly the size of the meat as some heat is drawn into the meat during cooking process. (That bird was a 30+ lb heat sink). I have done ribs as many as 9 racks at around 40-45 F, and although the outdoor ambient was higher I was able to achieve the desired 225 cooking temp after about 2 hours. (In cold situation I normally preheat for 2 hours +, however with the turkey I didn't. I couldn't because I didn't know how I was going to get that bird in there until right before I started, and didn't want to deal with burning myself on hot metal, so there was no preheat.)
I have never smoked or used the MES below 40 deg before. If I lived in a cold climate area where winter temps are regularly in the sub 40-30-20 deg range, and using the garage via vent hood is NOT an option, I would build a plywood, insulated enclosure, hinged door. It would easily work for me because I never baste and try to make it a hard rule, start to finish to not open the MES hatch.