KBB - April 2010 - (Page 78)
Proper ventilation takes proper planning
In a recent survey conducted by a leading appliance manufacturer in conjunction with the National Kitchen & Bath Association (NKBA), almost 90 percent of 573 kitchen designers said that their clients either “always” or “usually” rely on their professional opinions regarding a kitchen’s ventilation needs. In addition, 86 percent of the designers polled noted that client knowledge about kitchen ventilation appliances was considerably less than that of other appliances. For some industry professionals, the responses are not that surprising. “Homeowners tell us that they rely heavily on their kitchen designer to help them select the proper ventilation they need not only for the cooking surface it interfaces with, but for their unique cooking style,” said Brian Wellnitz, marketing manager for kitchen ventilation at Broan-NuTone. “The technical aspect of kitchen ventilation knowledge is one of the many beneﬁts a kitchen designer can bring to their client, increasing the value proposition of hiring a professional.” Although kitchen ventilation style and technology will continue to evolve, the process by which proper, effective kitchen ventilation is achieved remains based on proper planning and the incorporation of the following steps. cooking by pushing the heat plume outside the hood’s capture area, thus allowing the particles within the plume to land on surfaces, and odors to linger for longer periods of time. Windows and patio doors that are frequently opened are a prime source of crosscurrents; others include ceiling fans, forced heating registers or garage entry directly into the kitchen. Taking simple precautions, such as creating a two-tier counter with a raised portion, can prevent crosscurrents from moving across the cooking surface, thus reducing their effects.
DUCTING THE HOOD
• Consider your installation options. If code and building regulations permit ventilating to the outdoors, determine possible termination points on the home’s exterior and work back to possible hood locations. Pinpoint the paths that offer the shortest runs with the fewest turns and note the size limitations for the duct. When it comes to duct size, bigger is always better! • Match the hood to the installation. Once duct size options are determined, consider only hoods that connect to that size duct without being constricted. Hoods with larger duct connections—those requiring larger ductwork than will ﬁt the installation parameters—demand transitions that will constrict the air flow and should only be considered if reduced performance and higher sound levels are acceptable. • Simplify ductwork connection. Look for hood models that match the location ductwork. Some hoods only offer a duct connection out the top of the hood. Others offer greater flexibility by allowing duct attachment through the top or back of the hood, or even allow rectangular or round connections.
• Design it in. If you consider the ventilation ﬁrst when designing a kitchen, the level of challenge drops dramatically regarding duct installation and application issues. In addition to providing ventilation at the cook source, consider adding it near wall ovens and over sinks and prep surfaces to help remove excess heat, steam and odors. • Consider current and future needs. Design for your client’s current and future requirements. Will access to controls be an issue? Will lighting requirements change? According to Wellnitz, homeowners, especially baby boomers, are requesting brighter, more even lighting that reduces shadows and “makes it easier to see instructions, measurements and pot/pan contents.” • Recognize that recirculation is not ventilation. Many hoods can operate in two ways. Ventilation removes airborne particles to the outdoors, and recirculation removes particles from the immediate cooking area while most of the vapors stay in the home. This in turn can diminish the indoor air quality (IAQ) and increase the damaging effects to surrounding surfaces. In fact, some cabinet manufacturers void their warranties if adequate cooktop ventilation is not provided. • Observe and address crosscurrents. Strong crosscurrents can affect a range hood’s ability to capture vapors and grease from
• Determine the cooking equipment requirements. Use the manufacturers’ recommendations or the following formulas as a starting point to gauge cfm for wall hoods: 1) Under 60,000 Btu or for electric cooktops, estimate 100 cfm per ft. of cooktop width, or 2) over 60,000 Btu, estimate 1 cfm for each 100-Btu output of the cooktop. • Consider the user’s level of cooking usage. Are they the “warm the soup up” type or more “culinary extraordinaire”? The starting cfm level for the former could be reduced without having a negative impact, whereas the latter may need increased cfm to achieve operational satisfaction. Also keep in mind that the addition of a grill or griddle in a cooktop requires an addition of up to 200 cfm to the estimation. • Adjust for hood style and installation. A sleek hood may not have an internal blower that is large enough to produce the needed
Continued on page 80
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April 2010 / www.kbbonline.com / The Ofﬁcial Sponsor of KBIS www.kbis.com Jully2004
Table of Contents for the Digital Edition of KBB - April 2010
KBB - April 2010
Cover Story: In the Mix
KBB - April 2010