On further thought, two high vents, two low vents. Winter: lower vents on (one inlet, one outlet). upper closed. Summer: upper vents on (one inlet, one outlet

On further thought, two high vents, two low vents. Winter: lower vents on (one inlet, one outlet). upper closed. Summer: upper vents on (one inlet, one outlet). lower closed. The vents should be far apart to ensure cirulation (definitely not next to each other).