closing rear fuselage

How many of you guys are closing off the rear of your fuselage to keep the air from drifting foward ? I've been thinking I would close it off, but thought maybe others had some thoughts, pros & cons !

If you close off the aft end of the cockpit, where is the intake vent air going to go? You need a certain amount of circulation.

closing fuselage

Mel, I understand if air is coming in the vents it obviously needs an outlet, but I also dont want cold air seeping from the rear when my vents are closed

Mike no need to answer you are really having a bad night !!