This study proposes a rotating hygroscopic curtain to control indoor relative humidity. The curtain continuously exchanges heat and moisture with the two environments: the internal space where the curtain undergoes absorption and the space between curtain and glass window where it undergoes desorption releasing the collected space moisture to the exhausted airstream. In this work, a theoretical model is developed for the curtain system with an integrated indoor space modal to study the rotating hygroscopic curtain feasibility in performing indoor dehumidification. An experimental setup was built inside climatic chambers for validating the model predictions of room air temperature and moisture removal rate. Experimental data of the curtain-absorbed moisture and the chamber indoor humidity showed good comparison with the model simulation values. A case study was evaluated to predict the effectiveness of a highly moisture-absorbing cotton curtain used inside an office in Beirut City having an area of 42m(2). At a given load, the hygroscopic curtain maintained an average relative humidity of about 65.7% when rotating continuously at a speed of 1.5rpm compared with a value of 71.1% when the curtain was stationary. Copyright (c) 2015 John Wiley & Sons, Ltd.