Actually... I noticed it slightly. I would not say it stays so warm... but definitely not as cold as outside. The interior is literally air tight. I notice when I am driving highway, I will crack the windows and feel my ears want to pop from change in pressure... never had that with any other car. Also, with the amount of fluids the car has under the hood, it should keep a good amount of heat under there; useful for when I turn the car back on and feel nice and warm after leaving it even two hours.