April 02, 2023 9 min read
Do you find your kitchen gets smoky and stuffy while cooking? A range hood can solve that problem, but choosing the right one is important. A range hood helps keep your kitchen air pristine by removing potent smells, smoke, and other particulates.
If you're in the market for a new range hood, you may have encountered the term "CFM.” If you are perplexed by it, rest easy; you are reading the right article.
The CFM value of a range hood is an important factor to consider when choosing one, and you will learn why. This article will explain what a CFM is, why getting it right is important, and what factors to consider before choosing a CFM for your range hood.
Let’s dive in.
CFM stands for cubic feet per minute, and it is a measure of the volume of air a range hood can extract in a given amount of time. The CFM number reflects the ventilation power of any range hood. It demonstrates the strength of the blowers, as a high CFM range hood can affect a larger surface area.
The CFM rating of a range hood is important because it determines how effectively it can remove smoke, steam, and other airborne particles from your kitchen. The higher the CFM, the more air a range hood can move.
A range hood with a low CFM may be unable to keep up with the amount of smoke and grease produced when cooking, which can lead to poor ventilation and unpleasant odors. On the other hand, a range hood with a CFM that is too high for your kitchen can create too much negative pressure, making it difficult for the hood to work efficiently, which generates excessive noise and wastes energy.
Finding the right balance is crucial when selecting the best range hood for your kitchen. For example, a large kitchen with a gas range that expels hot gas and where meals with strong odors are regularly cooked will need the ideal range hood CFM value to be high.
The common CFM rating for range hoods can vary depending on the size of the range hood, the type of range hood, and the size of the range or cooktop it is designed to be used with.
Generally, range hoods for residential use have CFM ratings ranging from 200 to 900, with smaller cooktops or ranges requiring range hoods with CFM ratings of 200-400 and larger cooktops or ranges requiring range hoods with CFM ratings of 400-900 or more.
Here are some standard CFM ratings based on the type of cooktop for range hoods:
For some standard CFM ratings based on the type of range hoods:
Not all range hoods are created equal; from low-end 150 CFM range hoods to powerful 900 CFM ones, kitchen range hoods come in an astounding variety of CFM ratings.
Before calculating and settling on the best CFM number for your range hood, there are a few essential factors to consider. Considering these factors, you can determine the appropriate CFM for your range hood and ensure it effectively removes smoke, steam, and odors from your kitchen.
The size and layout of your kitchen are crucial factors that play a significant role in determining the correct CFM rating for your range hood. It affects the effectiveness and overall efficiency of the range hood. A simple rule of thumb is that your range hood should be powerful enough to recycle the air in your kitchen 15 times every hour or once every four minutes.
A larger kitchen will require a range hood with a higher CFM rating, as there is more air to circulate and clean. Similarly, a smaller kitchen will require a range hood with a lower CFM rating. If your kitchen range hood is too powerful, it can cause several issues, like excess noise, which can be unpleasant and distracting.
Your kitchen layout includes positioning the stove, windows, and other kitchen equipment. The location of the cooktop and other appliances affects the placement and type of the range hood. If your cooktop is located on an island rather than surrounded by walls, you may need a more powerful range hood.
When selecting the appropriate CFM (cubic feet per minute) for a range hood, one of the most critical factors is your stove type. The four main types of stoves are gas, electric, induction, and dual fuel, and each type has its unique heat intensity.
Every stove measures heat intensity in BTUs (British Thermal Units), which is the heat required to raise one pound of water by one degree. A gas stove will produce more heat than an electric stove, which means it will have a higher BTU output and require a range hood with a higher CFM rating.
Typically, for gas stoves, a range hood with a CFM between 300 and 900 is required, depending on the BTU output of the stove. Electric and induction stoves require a range hood with a CFM between 200 and 400. Dual fuel stoves often require a range hood with a CFM between 400 and 600.
The size of your cooktop plays a crucial role in determining how many CFM your range hood needs. The relationship between cooktop size and range hood CFM is relatively straightforward.
As the cooktop size increases, the amount of heat generated also increases. Similarly, the larger the cooktop, the more steam and smoke it generates. As a result, you need a range hood with a higher CFM to effectively remove the heat, moisture, and smoke generated by a larger cooktop. In contrast, a smaller cooktop generates less heat, steam, and smoke and requires a range hood with a lower CFM.
Cooktops come in different sizes, ranging from 24 inches to 48 inches or more. A 24-inch cooktop typically requires a range hood with a CFM rating of 250-400, while a 30-inch cooktop needs a range hood with a CFM rating of 300-600. A 36-inch cooktop requires a range hood with a CFM rating of 600–900, while a 48-inch cooktop needs a range hood with a CFM rating of 900–1200.
It's important to note that the above CFM ratings are just general guidelines, and as a general rule of thumb, you should select a range hood with a CFM that is at least equal to the size of your cooktop in square feet.
Ductwork plays a crucial role in determining the CFM requirements of a range hood. The ductwork's size, length, and design can impact how much air a range hood can move. If the ductwork is too small or poorly designed, it can reduce the range hood's CFM and cause the kitchen to become smoky, humid, and uncomfortable.
The standard rule is that the width of the ducts is inversely proportional to the CFM rating, so the higher the CFM number of a range hood, the wider the vent. Attaching an incorrect duct with a narrow diameter will reduce the range hood's CFM rating. A well-designed ductwork system ensures that the range hood can effectively remove smoke, odor, and heat from the kitchen. A poorly designed ductwork system with inadequate makeup air and tons of backdraft can lead to inefficient ventilation, resulting in a smoky and humid kitchen.
This is an often overlooked factor crucial when deciding on a CFM rating for a range hood. Your cooking style is essential because your style determines the level of pollutants you generate. Different cooking styles produce varying amounts of smoke, steam, and heat that must be removed from the kitchen to maintain a comfortable and safe environment.
For example, if you cook many stir-fried dishes or deep-fried food, you generate a lot of smoke, steam, and grease, requiring a more powerful range hood with a higher CFM rating. On the other hand, if you mostly do light cooking or only cook occasionally, a range hood with a lower CFM may be sufficient.
Mounting height can have an impact on the effectiveness of a range hood and can affect the required CFM rating for the hood.
When a range hood is mounted at a considerable distance above the cooktop, it may require a higher CFM rating to effectively capture and remove smoke, steam, and cooking odors. This is because the further away the hood is from the stovetop, the more air must be exhausted.
Conversely, if the range hood is mounted lower to the cooktop, it may require a lower CFM rating because less air needs to be moved to effectively capture and remove smoke, steam, and cooking odors. That is why ceiling or wall-mounted range hoods are the most powerful, as they are often far from the cooking area.
Range hoods come in different vent hood styles, which can impact the CFM rating selection. Different hood styles, such as wall-mounted, island, or under-cabinet hoods, may require different CFM ratings to remove smoke, steam, and cooking odors effectively.
Vent hoods mounted right above or close to the cooking range often require less CFM than those farther away or centrally placed. For example, an island hood typically requires a higher CFM rating than a wall-mounted or under-cabinet hood because it is located in the center of the kitchen and must draw smoke and steam from a larger area. The specific style and location of the hood will influence the appropriate CFM rating needed for adequate ventilation.
The noise level of a range hood is an essential factor to consider when selecting the CFM rating. The relationship between CFM and noise level is straightforward: the higher the CFM rating, which typically means a more powerful motor, the louder the range hood will be.
However, it's essential to remember that noise level is not directly proportional to CFM. A range hood with a high CFM may not necessarily be louder than a range hood with a lower CFM, as other factors, such as the design of the range hood and the quality of the motor, also play a role.
A range hood with a well-designed motor and a good-quality blower will be quieter than one with a poorly designed motor and a lower-quality blower. Similarly, a range hood installed close to the cooking surface will be louder than one installed further away. It's also worth noting that the noise level of a range hood may increase over time as the fan and motor wear down.
The cost is among the most important considerations when choosing the right CFM for a range hood. A higher CFM range hood may be more effective at removing smoke and odors, but it may also be more expensive to purchase and install. On the other hand, a lower CFM range hood may be less expensive, but it may not be as effective at removing smoke and odors.
Also, the cost of range hoods is influenced by several factors, including brand, size, materials, and features. High-end brands may offer more advanced features and higher-quality materials, which can increase the cost.
Finding a balance between cost and performance is essential when selecting the CFM rating for a range hood. A high-quality range hood with the appropriate CFM rating can improve indoor air quality and prevent damage to cabinets and walls by reducing the buildup of moisture and grease.
At first glance, the size and power of a range hood may seem like the most important factors to consider when selecting one for your kitchen. However, another crucial consideration that is often overlooked is local building codes.
Building codes often set out minimum requirements for ventilation in kitchens to ensure that indoor air quality is maintained and the risk of fire is reduced. For instance, if a local building code requires a minimum ventilation rate of 100 CFM for a kitchen, you must select a range hood with a CFM rating of at least 100 or higher.
Failure to comply with local building codes could result in costly fines or other penalties and compromise the safety and comfort of your kitchen.
We've reviewed the factors affecting how many CFM your kitchen hood needs. Each factor is essential and must be addressed to avoid getting an inefficient range hood. You must factor each into your decision-making process, and you won’t get a unit with too much CFM or, worse still, too little CFM. Electric range, range hood fan, cabinet range hood, makeup air