Performance of Microwave Range Hoods Compared to Traditional Range Hoods

Venting range hoods enable efficient removal of odors, moisture, and pollutants generated from burners and cooking
activities. Appliances that combine a microwave oven and exhaust fan (described as “over the range” microwaves or OTRs)
are popular in the U.S. for their space saving utility. Prior to this study, there were very few published data on the
performance of OTR microwaves for installed airflow and capture efficiency (CE) compared to traditional range hoods
(RHs). In this study we conducted laboratory performance assessments of six OTRs representing models that were observed
to be present in numerous California new homes, including three with airflow and sound ratings certified by the Home
Ventilation Institute (HVI). Performance testing was also conducted on two RHs. The performance testing included exhaust
airflows, sound level and CE. They were evalautedusing a mock- kitchen. Capture efficiency was measured using a dynamic
mass balance test with CO 2 emitted from gas cooking burners as the tracer and pots of water being heated on the cooktop.
The OTRs met the airflow requirement of ASHRAE 62.2 for kitchen ventilation. The new data combined with prior studies
indicates that OTRs have similar CE vs. airflow relationships as conventional range hoods, ranging from 40% to 85% for the
front burners and 60% to 100% for the back burners. As installed in homes, OTRs have similar peak airflows as RHs of
comparable costs but tend to be more noisy