Homemade hybrid fan filters still work

Someone last decade suggested a homemade filter for the hybrid fan intake next to the rear passenger seat. I started making them out of the thin foam sheets for air conditioners bought from local hardware stores. The intake grill is hinged at the bottom; it's simple to rotate the whole piece of plastic forward, slip out the dirty one and slip in a clean one and snap it shut. I change mine every time I change the engine and cabin air filters. I changed mine again today and it was dirtier than usual from dust and dog hair. Without that filter all that dirt and debris would be collecting down there in the back, interfering with the hybrid battery cooling fan.

For those drivers new to the 2nd generation Prius scene it is well worth taking the 3 or 4 minutes and cost of about 20 cents per filter to protect your car a little bit more.