I Have A Vertical Brinkman With Waterpan. I Took A Furnace Planium And Added 2 Inches Of Insulation To The Smoker Then Put The Planium Around It. I Did Not Do The Door. I Already Had The Holes Drilled In The Charcol Pan And Thought That I Was On Top Of The World . I Put The Charcol In The Pan And Waited For The Temp To Come Up Boy Did It Come Up. When I Pulled The Pan It Was Reading 350 Degrees. I Covered The Holes That I Drilled In The Pan . Going To Try It On Sunday I Hope That By Cuting The Air Down It Will Cool The Temp Down.