Modeling indoor humidity in homes
Indoor humidity levels in a home influence not only occupant comfort and indoor air quality but also the durability of the building, especially in cold climates. A common method for estimating humidity levels is moisture balance modeling, which generally considers moisture sources, sinks, and buffering-that is, moisture exchange with hygroscopic materials including the building structure and furnishings (e.g. carpet, furniture, books, etc.). Considerable effort in the building research community has recently been devoted to improved characterization of moisture buffering. Researchers at the Forest Products Laboratory undertook a critical assessment of the literature to determine the reliability of other parameters, namely the rates of moisture production and air exchange in houses. One of the main conclusions of this review was that a key model input, the rate of moisture production, can vary considerably from house to house. Furthermore, the review found that current values in an engineering standard for moisture design analysis are based on a rather limited data set. Finally, the review outlined research needed to establish greater confidence in design values for moisture production in homes.