The CEA 144 is a low-cost, wall-mounted, continuous infrared carbon dioxide gas monitor contained in a rugged steel enclosure with digital display. Ranges of 0-2,000 ppm, 0-5,000 ppm, 0-2%, 0-5%, 0-10% and 0-100% are available. The unit includes linear 0-1 VDC and 4-20 mA outputs, is easy to install and operate, and is available with an optional contact closure relay. The CEA 144 is applicable for use in welding, cooling systems, hazardous environments, laboratory and research projects, and various other applications where CO2 levels have to be monitored and/or controlled.