Hygrothermal loads in building structures may lead to degradation failure of building materials, as well as to poor indoor air quality. For these reasons, the need to understand emissions caused by hygrothermal loads in building materials has increased during recent decades. Although air is a combination of chemical, physical, and biological factors, only little attention has been focused on interdisciplinary approaches. An experimental apparatus was designed and constructed to measure emissions from building materials during flow of modified air through or along the material. The purpose of this apparatus is to investigate the effects of relative humidity (RH), airflow rate, and temperature on chemical, physical and biological emissions from thermal insulations. The advantages of this low-emission apparatus are clean air output, uniform conditions and interdisciplinary measurements in a single chamber. The apparatus consisted of a system which was capable of achieving a wide range of conditions. Validation studies of the apparatus indicated that its fluctuation limits were (1) for RH, (2) for temperature, and (3) 0.3 l/min for airflow rate when the airflow rate was adjusted to 4 1/min. The air quality measurements indicated that particle concentration, total concentration of volatile organic compounds (TVOC) and microbiological levels were close to zero in the properly cleaned empty chamber.