Any cover for the cooking vents

I recently move to this place and I noticed that the the cool outside air is coming into the vents to the unit and keeps my 1DK apartment cold.

Is there some sort of cover for those so I don’t over use my heater and rack up so much ¥ for my electric bill?

Cover or any tricks you guys do to keep the outside cool air for coming in?

Thank you

by throwaway_acc0192