Ventilation systems are now used to ensure optimal indoor temperature and humidity in contemporary buildings such as showrooms, museums, offices, and homes. Winter indoor humidity can be very low due to the low humidity contained within fresh outdoor air supply. Humidification becomes necessary to raise indoor humidity, which also raises primary energy demand. Three approaches have been examined in a research project to reduce humidification/dehumidification energy consumption: (1) Moisture storage (absorption and emission of moisture-peaks) (2) Air flow control optimization (3) Moisture recovery by the ventilation system This paper focuses on the first approach, air humidification and dehumidification using moisture storage. A model was developed to illustrate both the microscopic and macroscopic hysteresis of moisture storage, and transport capacities of fibrous materials. The necessary parameters for the model have been obtained using measurements from a number of different materials that were used as humidity buffers. Precise equipment to measure humidity was constructed, tested, and used over a very long measurement period, during which detailed measurements of moisture absorption and emission were measured from different types of fibreboard sheets. The simulations generated by the model showed very good agreement with the measured results. (C) 2011 Elsevier B.V. All rights reserved.