This invention is directed to a removable insulation curtain for a vehicle. The removable insulation curtain is made of a multi-layered flexible cover and can be used to cover openings in the vehicle, such as side and rear doors. The curtain is secured to the vehicle with removable fasteners around the perimeter of the door openings. The removable insulation curtain has a slot for people to enter and exit the vehicles without taking the curtain off and a window to let in outside light. The slot of removable insulation curtain enables side and rear doors of a vehicle to be used for ingress and egress while the tight fitment around vehicle doors reduces fluctuation of interior temperature relative to ambient temperature.