This paper presents the results of two field studies for an indoor air quality (IAQ) monitoring system, utilizing Echelon technol. to eliminate the need for direct wiring of remote sensing units to a central datalogger. Up to eight sensors of differing technol. and up to 256 remote units can feed one datalogger. The results can then be analyzed and displayed in various formats (i.e., tables, graphs, and reports) or used as input to heating, ventilation, and air conditioning (HVAC) and other control devices. The system was installed and collected data during a summer test period in a com. building and a winter test period in an industrial facility. These sites were chosen because results of previous IAQ assessments showed elevated CO levels. The com. building is a municipal facility that houses public works maintenance and engineering functions. The industrial location is a manufacturer of machined metal parts and shares shipping and receiving docks with an adjacent foundry and casting operation. The system used in these field tests consisted of three remote sensing units, which were plugged directly into standard elec. outlets in various places throughout the sites, and one central datalogger which polled the remote units and collected the data. The remote units, as configured for these field tests, continuously measured methane, CO, relative humidity (RH), and temperature (T). Other sensors, including carbon dioxide (CO2) and specialty gases, can be utilized. In both tests, the data was collected over a period of several weeks. The data collected showed quick detection and sensor recovery of CO "spikes" and accurate tracking of T and RH variations. No methane was detected during the field tests. The field tests showed the viability of this system to monitor IAQ parameters for the purpose of alarm and control functions.