Ask the Architect

Do we need an exhaust hood?

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Q. We’re working with a kitchen designer, and they’re planning a big exhaust hood over our burners. I just don’t see why we need one, and it’s much more expensive than I thought. The designer is saying we must have one and is really pushing it (and I’m sure there’s a better commission in that sale). Is it required? Why do we need it? We have an open kitchen, and windows, as well Besides, on a cold day it seems like of waste of energy.

A. I get exhausted just thinking about your exhaust fan. Venting above your cooktop is actually required in the mechanical code, and for good reason. The quality of indoor air is potentially a serious problem, according to the Centers for Disease Control and prevention.

Combustion pollutants from fireplaces, boilers, gas ranges and ovens can lead to illness and eventual death. An estimated 3.8 million people become ill and die each year from respiratory causes, and we rarely think of the air we are breathing in our homes as a reason. We spend between 75 and 90 percent of our time indoors, believe it or not, including your home, workplace and car. We inhale recycled air or air filled with impurities most of the time, believe it or not.

Your air duct hood in the kitchen becomes more important to you under those circumstances. Most venting in kitchens is actually undersized or not maintained, building up restrictions like dust and grease over the years. Some people complain about the noise, but conversation is rated at 4 sones on the noise level scale, while an exhaust fan is rated only slightly higher, at 6 sones. If the fan noise level is higher, the vent fan may have been installed incorrectly or is slowing down or struggling with grease build-up.

Open kitchens don’t solve the problem, because smoke and contaminants move freely through your home. You should ventilate even when boiling water, or using any open flame or anything that produces heat, moisture or smoke. The higher the heat (BTUs), the larger the hood should be. It should extend 3 inches beyond the length and width of the cooking surface.

As a general practice, remember that rooms should also not be isolated, because spores and fumes that develop are also isolated, cut off from balanced air flow, just by keeping doors closed. It’s best to keep room doors open most of the time, except of course for privacy. Good air flow from room to room promotes better air quality and better health. This is especially important during the months when we keep the windows closed.

I’m not sure about the commission for the sale, but the kitchen vent fan and hood actually serve an important purpose, so I’d recommend including the hood as a feature of your kitchen design and not excluding the exhaust fan. You’ll breathe easier knowing it may be easier to breathe. Good luck!

© 2019 Monte Leeper. Readers are encouraged to send questions to yourhousedr@aol.com, with “Herald question” in the subject line, or to Herald Homes, 2 Endo Blvd., Garden City, NY 11530, Attn: Monte Leeper, architect.