The impact of operating pressure on residential bathroom exhaust fan performance

Abstract

This study quantified the performance impact of increasing operating pressure on residential bathroom exhaust fans based on the comparative analysis of airflow, efficacy, and loudness on more than 80 different residential bathroom exhaust fans with alternate current motors. The fan performance data were measured in a well-instrumented laboratory environment that includes a calibrated nozzle airflow chamber and a six-microphone reverberant sound chamber. Fan airflow rates, efficacies, and loudness were experimentally determined to investigate the impact of external static pressure (ESP) on fan performance at the rating pressure of 0.1in. w.g. (25Pa) and the higher field-observed pressure of 0.25in. w.g. (62.5Pa). An analysis of results showed that fan performance was strongly affected with increasing the ESP. For example, when the ESP was increased from 0.1 to 0.25in. w.g. (25–62.5Pa), the average value of fan airflow rate decreased by 19%, efficacies were penalized by 16%, and the loudness increased by 75%.