Ok so heres what you do, don't open your incubator in the middle of a snow storm, Nor should you try to incubate your eggs in an open room with a zippo.
I don't see why everyone thinks you need more heat, 11 inch is 20 watts a foot right? I'm using a 10 watt heater in my 70 qt cooler incubator, i know yours is bigger but still, you got twice the heat.. I open it, check on things, close it it drops about 5 degrees, in about a minute or 2 its back to temp. water works wonders.
Test it, open it it long enough to check on all your tubs and see how long it takes to get back up to temp. If it reasonable, your fine.