A system includes a latent exchanger and first and second fans. The latent exchanger includes first and second chambers and one or more membranes separating the first chamber from the second chamber. The one or more membranes are gas-impervious. The first fan generates a greenhouse airflow that flows from a greenhouse, into the first chamber, and then back to the greenhouse. The second fan generates an outside airflow that flows from an outside environment, into the second chamber, and then back to the outside environment. The one or more membranes are configured to permit moisture to flow through the one or more membranes from the greenhouse airflow to the outside airflow through the one or more membranes and to prevent carbon dioxide from flowing through the one or more membranes from the greenhouse airflow to the outside airflow.