I hate plugging vents. I keep a xenon under cabinet light ( flat like a hockey puck) with cord that I can plop into the incubator if the temps fall too low. They're a hot light and quickly bring up temps. Warning hot hot light. Never point one of those at eggs, plastic or foam walls I keep a jar of water in my big bator for thermal mass and point it at that. In smaller ones I have tile and can point it at that. It helps to have options. Luck!