My vent exhaust shield side (opposite end of cord) is against a wall. The heat doesn't seem to rise as good and circles back down below to the tank surface. Can I switch sides with the exhaust shield and just put it on the corded side? Or is there a reason it's on the left side of the fixture? If I can switch sides for the exhaust I assume I keep the label side on the vent slot side no matter what. Please advise.