Toward Better Hoods
To encourage the development of better range hoods, the LBNL team is working with other researchers and several major appliance manufacturers to design a capture-efficiency test method for universal use. Ultimately, they hope, capture efficiency will replace airflow as the most prominent performance metric printed on range-hood labels and as the basis for ENERGY STAR ratings.
"Basically, the push in the industry is to … get at a more intelligent design that really accomplishes what the consumer is looking to do, which is remove the pollutants from the space in a potentially more energy-efficient manner," says Mike Moore, a consultant who represents appliance manufacturers on building performance and environmental quality issues.
Sherman says a capture-efficiency threshold is being considered for inclusion in the next update of ASHRAE 62.2 (Singer and Walker suggest a lower limit of 80%), meaning that within a few years the code itself could move from merely requiring mechanical kitchen ventilation to demanding range hoods that perform well. "Just having any old hood doesn't tell you how good that hood is at capturing what you actually want to capture," Sherman says.
Another hood element likely to be included in the next version of ASHRAE 62.2, whether as a requirement or as a recommendation, is the use of auto-on features triggered by light sensors, heat sensors, or wireless signals between the range and the hood, says Michael Lubliner, a building science specialist with Washington State University. He says these features, currently available on a few high-end models, could improve the devices' effectiveness across the board. In addition, investigators suggest that kitchen exhaust devices could eventually be outfitted with HEPA and carbon filters to handle NO2 and particulate matter.
Ultimately, what's most important is to develop an affordable, automatic range hood that's quiet and effective. "That's where we need to end up as an industry," Walker says. "It's all doable, and it's not complicated."