I got this idea from a thread I seen by q3131a ( Mike ) and I thought this should work. I went to H.D. and got a 4x8x1 sheet of foil backed insulation for $14.00. Measured it all out , cut it to size ,cut out the vent holes and used foil tape on all the edges, and screwed it to the smoker. The top vent I used a 6" coffee can cut down to 1 1/2" and used it as a chimney to keep the hot exhaust away the insulation. I preheated the smoker to 300 deg. for about 10 minutes and it seemed to hold up. I smoked 15 lbs of venison sticks that day for my first test. Outside temps started out at 30 deg. and a little wind . I had the main burner on low and the cylinder valve just cracked a little to keep the temps at 130 deg..For the next 6 hrs the smoker performed great and used very little propane for heat. I must say for the first test it worked great. p.s. Now I need colder weather for a real test Thanks q3131a ( Mike ) for the idea !!