Inadequate kitchen cooking ventilation is more common than many people realize, even in recently built homes. Generally, the hoods are not sufficient for the stove size, or they are improperly vented. The accumulation of smells or smoke while cooking indicates that the fan may not be adequately or properly vented. Many individuals believe that having a fan alone is sufficient to manage ventilation; however, this is not always the case.
This article will dive into the top 4 problems faced with poor cooking ventilation and solutions on how to solve them.
Common Problems with Kitchen Cooking Ventilation
1. Wrong Fan Size
When we talk about fan “size,” we don’t mean the physical size of the hood unit; we mean how much air the unit circulates. Smaller, lower-CFM (cubic feet per minute of air moved) hoods are typically less expensive. These less expensive units have cheaper fans that move less air and make more noise. The higher the CFM, the more air that’s moved, the further away the range can be from the hood. Flush ceiling-mounted hoods need to be properly sized because they’re farther away.
2. Improperly Routed Ventilation
In many cases, unbeknownst to the homeowner, the hood fan doesn’t ventilate at all. Instead, we find many cases where the hood fan only circulates the air away from the stove and back into the room. This is especially prevalent in multi-unit apartment and condo complexes. Adequate hood ventilation often isn’t installed because it requires extra ductwork (aka more time and money), and hood placement can make it challenging to add ducts to vent properly.
When routing ductwork outside, the longer and more twisty it is, the less efficient the fan will be. In an optimal situation, it is advised not to extend the venting ductwork beyond 30 feet.
Range Craft says, “your range hood duct shouldn’t exceed 30’ for a straight run, 25’ for a run with one elbow, and 20’ for a run with 2 elbows. The shorter the duct, the better. If your ductwork is too long, your kitchen air cannot reach the outside.” The longer the vent, the more buildup of grease, dust, etc., in the ductwork, making it a safety hazard. The fan has to push all the air out along the length of the vent, which decreases its efficiency.
3. Hood at Wrong Elevation
Having your hood the wrong distance from your stove top can also create issues. Oftentimes, we’ll see a kitchen with 9 ft ceilings, leaving a large gap between the hood and range, which doesn’t lend to efficient ventilation.
It is recommended that indoor range hoods be mounted between 28 and 36 inches above your cooktop. You may see varying heights recommended depending on your cooktop type (gas, electric, or induction). You should always consult your builder and an appliance specialist before installation.
As a general rule of thumb, KitchenAid recommends, “If you have an electric cooktop, range hoods should typically be 20–24 inches above the heat source. For gas cooktops, your range hood should be around 24–30 inches above the stove.”
What happens if your hood is mounted at the wrong height? If your hood is installed too close to the cooktop, excessive heat from the stove can damage it and shorten the motor's lifespan. You will also need to clean your hood more frequently, or even risk starting a fire. If the hood is too far from the cooktop, you may end up running the fan at a higher speed more often to compensate, which can shorten the motor's lifespan. You also risk losing money by ventilating the heated or cooled air circulating through your home, and some of the cooking fumes are likely to escape into the kitchen rather than up through the ductwork.
4. Seattle Requires ‘Makeup Air’
New homes are, in theory, airtight and well-sealed from new windows and doors. Hood fans, when running, create a vacuum effect within the house, drawing out air faster than it’s being replaced. In response, you have to create an avenue for ‘makeup air,’ which is a vent somewhere in the house that’s used to pull air from when the hood is turned on. Running a makeup air system is an extra expense. SDCI section M1503.4 states, “Exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (0.19m3/s) shall be mechanically or naturally provided with makeup air at a rate approximately equal to the exhaust rate.”
The Cooking Surface Determines the Amount of Ventilation You Need
BTU (British Thermal Units), aka the amount of heat output from the stove, and the size of the range determines how large the hood needs to be. Typically, you need a range hood that pulls at least 100 CFM for every 10,000 BTUs of your stovetop. Oftentimes, people install hoods that are the same size as the range because it is aesthetically pleasing, but it’s recommended to go, preferably, 6 inches wider.
Better Safe Than Sorry
Ensuring proper kitchen ventilation is one area you don’t want to guess on. Work with someone who can do all of this right for you the first time. You should work with a professional to choose the proper hood unit and determine the correct installation. As you can see from all of the challenges, a well-designed and properly vented range hood is critical to the safety and efficient use of a kitchen. Work with an experienced firm that can design and install range hoods in all different types of kitchen environments.
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