Nope, that whole section is like a return plenum. The moisture released by the heat is blown out to the incubator section. . The holes drilled in the divider restrict the return air flow, causing fresh air to be drawn into the fan/humidifier section. Vent slits at the top of the incubator section let air out due to warm air raises. Right now the RH% is 54% but I think thats dry due to the new pine shavings just added. I am getting ready for a dozen eggs sent by another forum member. Hope to be incubating some Jersey Giants by the end of next week.