As they say, the kitchen is the heart of a home. It is a space where families and friends gather to prepare meals and spend time together. However, without adequate ventilation, the kitchen can be a potentially dangerous area. 

Studies have shown  that the process of cooking food and even simply operating stoves especially gas appliances can emit numerous potentially hazardous chemicals and compounds. Because people use different heat sources to cook food, including gas, wood, and electricity, these can create indoor air pollution during cooking. In addition to that, natural gas and propane stoves can release carbon monoxide, formaldehyde and other harmful pollutants into the air while using a wood stove or fireplace to cook can result in high levels of indoor air pollution from wood smoke. Both of these activities can cause toxicity to people..

One of the most common air pollutants include Carbon monoxide (CO), Nitrogen dioxide (NO2), and Particulate matter (PM). They pose significant short- and long-term health risk especially when people are chronically exposed to them. These compounds are among the six primary pollutants monitored by the U.S. Environmental Protection Agency (EPA) through the Clean Air Act. They are frequently emitted from coal-fired power plants, vehicle exhaust pipes, and other combustion sources. However,  because in part to a ubiquitous and possibly surprising daily activity such as cooking, these same pollutants are found inside the home. Moreover, these pollutants are less diluted inside the home than they are outdoors. Hence, without proper ventilation in the kitchen and in the home,  these pollutants are frequently trapped inside which causes for the significant health effects living in the home. 

In addition, cooking can also produce unhealthy air pollutants from heating oil, fat and other food ingredients. Moreover, self-cleaning ovens, found in most modern homes, can create significant levels of pollutants as food waste is burned away. Exposure to such pollutants can produce or worsen a wide range of health problems such as nose and throat irritation, headaches, fatigue and nausea. According to the World Health Organization, exposure to such indoor pollutants can cause premature deaths every year secondary t o respiratory, cardiovascular and other systemic illnesses. Hence, this serves as a reminder of the inherent dangers of indoor cooking and of the vital importance of adequate kitchen ventilation.

Indoor Air pollutants

As stated above indoor air pollutants significantly contribute to the overall health of people staying inside the home. Hence, it is important to discuss the major and most common indoor air pollutants. 

  • Carbon Monoxide

Chemically speaking, Carbon monoxide consists of one carbon atom and one oxygen atom. It is connected through a triple bond. It is a colorless, odorless, tasteless gas produced by burning gasoline, wood, propane, charcoal, and other fuel. Carbon monoxide accumulates in hazardous levels when there are improperly ventilated appliances in a tightly sealed place or enclosed space. For example, a kitchen without proper ventilation. Carbon monoxide poisoning occurs when carbon monoxide builds up in the bloodstream. In concentrations above about 35 ppm, it binds to hemoglobin disrupting the capacity to carry oxygen in the blood. Hence, the oxygen is replaced with carbon monoxide which can lead to serious organ damage and eventually death. 

Signs and symptoms of carbon monoxide poisoning may include dull headache, weakness, dizziness, nausea or vomiting, shortness of breath, confusion, blurred vision, and loss of consciousness. If such symptoms occur, it is best to go to the nearest hospital for emergency before irreversible brain damage or even death occurs. 

  • Nitric Oxide

Nitric oxide is a colorless gas composed of nitrogen and oxygen. This compound, formerly known as laughing gas, contributes significantly to greenhouse gas which causes the major world phenomenon known as global warming. Nitric Oxide is one of the principal oxides of nitrogen and is considered as a free radical which means it has an unpaired electron on its outer shell. Because of this feature, it makes it highly hazardous and reactive. Nitric oxide is produced from vehicle exhaust and the burning of coal, oil, diesel fuel, and natural gas. They are also emitted by cigarettes, gas stoves, kerosene heaters, wood burning, and silos that contain silage. In environmental studies, nitrogen oxides create environmental health hazards through reacting with sunlight and other chemicals such as sulfur dioxide to form smog and acid rain. 

Nitric oxide primarily affects the respiratory system causing inflammation of the airways at high levels. It can also decrease lung function, increase the risk of respiratory conditions, and increases the response to allergens. To be specific, In Short-term exposure to Nitric oxide,  the health effects from breathing can include irritation of the respiratory system, eyes, and skin, worsening of respiratory diseases such as asthma, coughing and choking, nausea, headache, abdominal pain and difficulty breathing. On the other hand, the long-term exposure to low levels of nitrogen dioxide can cause Asthma and Respiratory infections. Sudden exposure to very high levels of Nitrogen oxides can cause death, genetic mutations, abortion, decreased fertility, and cardiovascular complications. 

  • Particulate Matter

Particulate matter is a term used for tiny particles found in the air. It can be formed in the atmosphere due to varied chemical reactions between different compounds or pollutants. Particulate matter includes dust, dirt, smoke, liquid droplets, and soot. Some of them may be large enough for the naked eye to see, but most of these particles can only be seen using magnifying tools such as the microscope. Hence, there are two kinds of particulate matter: the PM-10 which is the coarse type of particulate matter; and PM-2.5 which is the fine type of particulate matter. 

Particulate matter is emitted from vehicles, factories, construction sites, fields, unpaved roads, and burning of fossil fuels. However, even simple and daily tasks such as grilling food on charcoal or gas grills and cooking meals in gas stoves, or burning wood in a fireplace can produce particulate matter indoors. 

It must be noted that the size of particles is directly linked to their ability to cause multiple health problems. Exposure to small particles less than 10 micrometers in diameter poses the greatest problems may cause nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, increased respiratory symptoms  such as irritation of the airways, coughing, or difficulty breathing, and even premature death in people with heart or lung disease. Studies also show that chronic exposure to particulate matter can cause increased risk for the development of cancer.

The Science behind Kitchen Ventilation

Having proper ventilation is one of the most vital requirements when building your own home, especially when talking about the kitchen. Combining factors such as regional climate, home design, and natural ventilation is an effective means of keeping the whole space at a comfortable temperature while reducing energy consumption and maintenance. 

A circuit of air movement is created through a natural or built-in ventilation system. This circuit supplies fresh air into the space while allowing the existing air to exhaust. This air flow circuit is designed in order to take advantage of the changes in pressure that occur due to differences in temperature and humidity in the air. Hence, the science behind kitchen ventilation is manipulating the natural airflow into, out of, and within the kitchen through strategically placing entrance and exhaust vents, hood, and fans. This permits circulating clean and better air circulation throughout the space. 

A sample of a simple ventilation system is shown below:

 ventilation system

(Image lifted from: https://www.pdhonline.com/courses/m228/m228content.pdf)

By natural laws of nature, warm air has a lower density than cool air. This difference in density causes the warm air inside the kitchen to naturally rise to the ceiling. Using natural or artificial ventilation, indoor air movement is improved through overcoming barriers such as the ceiling. As seen in the figure above, ventilators go on the roof of the building in order to allow large volumes of warm air to escape. These ventilators permit the maximum amount of air to evacuate the space while making sure that rain, debris, or other materials are prohibited from entering the area.

In addition to these, ventilation systems allow better control of the interior temperature as the external temperature outside the home rises and falls. It is able to control the temperature through permitting air to exhaust from the space as required. There is a direct proportional relationship between the increased speed of incoming supply of air and increased rate of air movement throughout the space. This ability of artificial and natural ventilation systems can cool the space during very hot conditions such as during the summer or even during cooking. This in exchange saves money and energy. 

In designing the home, or specifically the kitchen, there are several factors that engineers or architects must consider in order to have an effective ventilation system. Every opening within the space will significantly affect the circulation of air, and in turn, the temperature inside. Hence, Intake and exhaust vents, as well as doors, windows, and the like should be taken with utmost importance because it affects  the air movement within the space. Moreover, internal factors such as walls, barriers, the placement of large equipment and more should also be thought of. The actual structure of the house is also important when designing a kitchen ventilation system. The orientation of the home can make a big difference when the temperature rises and falls throughout the day. Taking advantage of the fluctuations in the temperature can increase the effectiveness of a kitchen ventilation system. Lastly, other factors, such as the location of the home or the building the kitchen ventilation system will be installed must also be considered.

Types of Kitchen Ventilation System

As stated above, kitchen ventilation is a must for all homes. There are several interdependent units in a kitchen ventilation system. These units include a range hood, a grease extractor, and an exhaust fan. Moreover, most modern homes customized their ventilation system for aesthetic reasons. 

Ventilation in the kitchen is a must in order to get rid of smoke and humidity caused by cooking. Heat and grease from the said activity can also be eliminated with proper ventilation. Air pollutants such as carbon monoxide, nitric oxide, and particulate matter can also be removed through the kitchen ventilation system, reducing the risk of varied health problems secondary to long term exposure to such compounds. Lastly, proper ventilation helps eliminate overwhelming scent due to cooking meals. 

  1. Kitchen Range Hoods

A kitchen range hood consists of three main components: (1) a skirt or capture panel, also known as effluent plume, to contain the rising gases; (2) one or more grease filters; and (3) a fan for air circulation.

A range hood is a fan that is placed above the stove top in order to remove smoke, grease, and other particulate matter during cooking or food preparation. The ventilation fan within the hood forces air outside as long as it is on an exterior wall when a homeowner turns it on. Moreover, many range hoods available in the market are installed with lights that are frequently available in different materials and colors so they can match any kitchen aesthetic and decor. Furthermore, range hoods vary not only in style but also in installation. The traditional kind of range hood sits above the stove top, though it can also be mounted to the wall. The modern kind of ventilation has a slide-out system that can be removed easily and is usually hidden under the cabinet above the stove so that only the hood shows rather than the entire vent system.

There are two major configurations of extractor hoods: ducted, also known as vented, application, and ductless, also known as recirculating, application. 

rangehood

(Image lifted from: https://stuffswatch.com/ducted-vs-ductless-range-hood/)

On one hand, in a ducted application, air is released outside through a duct system found outside the home or building. This system has an air extractor blower. A ducted system permits for removal of all forms of airborne contamination. Moreover, this system eliminates the need for regular replacement of the filters and avoids the airflow restriction caused by them. However, in a home setting, ducted application can be impractical because of lack of space or ability to install a duct system, make-up air requirements, or the additional cost of heating or cooling the make-up air.

On the other hand, in a ductless application,an activated charcoal which serves as a filter is attached to the range hood system. This eliminates odor and smoke particles from the air in order to release clean air back into the kitchen. Hence, a ductless one recirculates heat and moisture into the kitchen. 

Range hoods are made from a wide range of different materials such as stainless steel, copper, bronze, nickel silver, zinc, tempered glass, wood, aluminum, brass, heat-resistant plastics, and the likes. In addition to that, range hoods often include built-in lighting in order to illuminate the cooking surface and include accessories such as backsplash panels, pot racks, shelf units, or dish racks. Most range hoods available today in the market are usually electronic, but some low-end models still utilize electromechanical controls. Modern range hoods can offer remote control, motorized height adjustment, thermal sensor, overheat protection, boost mode, delayed shut-off, filter cleaning reminder, active noise cancellation, temperature display, and user presets. More importantly, the main advantage of a range hood is that it can easily filter the airflow, without harming the edible materials and can be easily installed. 

With all these to give you more in depth knowledge about kitchen ventilation, here is a list of different range hoods available in the market:

  • Under Cabinet Range Hood
morden kitchen

(Image lifted from: https://rangecraft.com/what-is-an-under-cabinet-range-hood/)

This type of range hood is one of the most common types utilized for modern kitchen ventilation systems. Under cabinet range hoods, as the name implies, are installed under the bottom of a wall cabinet with ductwork hidden inside an adjoining wall. Just like all other range hoods, its purpose is to provide proper air circulation in the kitchen through removing smoke, steam, heat, and unpleasant odor that result from food preparation and cooking. 

Height of your cabinets and the width and depth of the range hood are one of the vital things you must consider when you are thinking of installing your own under cabinet range hood. If the range hood is very low, you are most likely to lose more headspace. Installing a range hood very high can reduce its capacity to remove grease, smoke, and combustion products from the kitchen. Most engineers recommend a width space of 2 to 3 inches on either side of the range hood for maximal and ideal kitchen ventilation. Additionally, under cabinet range hood has a built in fan that traps and absorbs grease so that combustion products will not build up on your cabinets or kitchen appliances. Fan speed and loudness should be considered when purchasing a range hood as it determines its efficiency and level of comfort when in use. Moreover, as time passes by, accumulation of grease and airborne particles can reduce the efficiency of under cabinet range hoods, and thus must be periodically cleaned to ensure capacity.

In addition to that under cabinet range hoods can either be ducted or ductless. There are a lot of different under cabinet range hoods available in the market and they work differently based on their level of efficiency and mode of operation. For most homes, in order to remove smoke and steam away from the cabinet doors to the suction end of the hood, under cabinet range hoods often extend about halfway across the stove. This design works best for those who cannot achieve the recommended clearance due to lack of space. Moreover, modern models permit users to slide out a shallow hood from the upper kitchen cabinet. This clears the range hood when not in use and allows you to access the upper cabinets without any hassle.

  • Wall-mounted range hood
morden kitchen

  (Image lifted from: https://www.amazon.com/KN4-36-Mount-Range-Glass-Stainless/dp/B016Z58TMO)

Wall-mounted range hood is ideal for homeowners who want to combine aesthetic and function while saving space in the kitchen. As it names implies, it is attached to the wall above your range. Instead of having a cabinet in the space over the stove, the hood is instead installed which is observed in most modern kitchen designs. Moreover, these hoods often come with a chimney that aids with the ventilation, and they frequently vent out through the exterior wall behind them.

In addition to that, a wall-mounted can add a design element and character to your kitchen. It adds a sense of personal touch to your cooking space. For this reason, it is slightly more expensive than under-cabinet hoods. With that some factors must be taken into consideration when choosing a wall-mounted range hood. These factors include: (1) CFM strength or cubic feet per minute which refers to the suction strength of the range hood. The higher the CFM, the better the suction capacity; (2) Filters which can come as stainless steel filters which are the easiest to clean or as a charcoal filter which needs soaking and scrubbing in order to remove dirt; (3) Size which usually measures between 30 inches and 48 inches. This means that you need to have an accurate measure of your kitchen; and lastly (4) Design which can include stainless steel finishes, tempered glass hoods, natural wood hoods, or ornated hood with features such as contoured designs, mixed textiles, or etched details.

  • Island or Ceiling Mounted range hood
 Ceiling Mounted range hood

(Image lifted from: https://www.habitusliving.com/products/elica-bio-island)

If your kitchen has an island, then you might choose to install a range hood located in the middle of the island. With enough kitchen space, Island hood installations are well suited for most kitchen islands and kitchen layouts. A major benefit of an island range hood is its central location within the kitchen which gives it an advantage that lets people handle the extra output that may come along with additional cooking burners and tools. This design lets people come together on the island and do multiple cooking without compromising proper ventilation of the area. With an island range and hood, you have a walk-around cooking area that is more spacious and conducive to team cooking. Installation of the hood permits you to cook, simmer, stew and fry foods just like you would with a non-island cooktop, however the only difference is you have more space to move around. Moreover, Range hoods make a dramatic statement in a room and are available in a variety of sizes, colors and materials. They come in a selection of modern materials such as copper, glass or even ceramic. 

  • Ventilator Power Rack Range Hood
Ventilator Power Rack Range Hood

(Image lifted from: https://www.frecan.pt/en/hoods/built-in/vetro-klin/)

This type of range hood is more seamless in style. This type of range hood is custom built or made-to-order. It contains blowers, grease traps, lights, and controls. Moreover, this variety of ventilation system can be added to existing cabinetry without having to renovate much of the available storage space. Because it is small, it can continuously be installed in the parts available in your kitchen, you do not have to remove any cabinets or adjust the space of the whole area. Hence, you can install them in your custom or wood hoods. Because they are custom built, they will surely fit into your own creation or into a shell of wood, plaster or metal manufactured by the contractor. Lastly, it frequently comes with an easy-to-clean, powder coat metal or stainless steel liner in to ensure an aesthetically pleasing yet easy-to-clean bottom for your hood.

2. Kitchen Exhaust Fans

Most kitchen ventilation products include an exhaust fan in order to aid dispersing hot air and grease. Just like the range hoods, kitchen exhaust fans are extremely effective when it comes to the extraction of air and any possible pollutants or other substances that may be present in the air during cooking or food preparation. Hence, they are a vital part of the general ventilation process because they can extract old and stagnant air out of your kitchen and permit it to escape through the external vents. There are basically two main types of exhaust fans that are also part of the kitchen ventilation system. This includes (1) a downdraft kitchen exhaust fan which is not frequently the most effective ventilation product,  however it is usually considered easy to install and to clean; and (2) Overhead kitchen exhaust fans or wall ventilation fans that make up the majority of vent fans, as hot air rises naturally. This type of fan sucks up smoke and other particulate matter present in the air and sends it outside or filters it and returns it to the kitchen. Both of these types are explained further below:

  • Downdraft Ventilation/Exhaust fan
Downdraft Ventilation/Exhaust fan

      (Image lifted from: https://planforward.net/design-matters/in-todays-kitchen-design-concealed-range-hoods-are-popular)

If you have limited kitchen space, then a less common ventilation system called a downdraft ventilation fan might be of help to you. This type of ventilation fan is kept inside of the cook space hidden until you release for use. It pops up along the back of the range once you need to run the fan. Moreover, it can also be a part of a kitchen island or against the wall to work as an exhaust fan. Because it does not obstruct any design, these are good as a complement to your modern kitchen, adding an element of surprise to the space. Furthermore, it offers an advantage of being easier to clean than full range hoods and having a cheaper price compared to range hoods such as the wall mounted or island fixed range hoods. However the downside of this ventilation system is that it only works for cooktops. They also do not come with lighting unlike the range hoods.  Moreover, because they only rise about 10 inches, downdraft ventilation can be inefficient at removing steam and grease emitted from tall pots.If you are used to cooking with multiple pots and pans, the vent will struggle to keep up with ensuring proper ventilation. 

  • Wall Ventilation Fans
Wall Ventilation Fans

(Image lifted from: https://www.yoycart.com/Product/43168769728/)

If you have limited space and you do not really want to install a range hood, then you can opt to install a wall ventilation fan. It is helpful in clearing smoke and unpleasant odors and in maintaining proper air circulation during meal preparation. However, it may not work as well like range hoods. It also clear odors and fumes slower than the traditional range hoods. Moreover, without a range hood, this type of exhaust fan cannot remove grease hence you may find small bits of grease building up along the walls of your kitchen. Thus, it is highly recommended that a wall ventilation fan be paired with a range hood so that it can facilitate the removal of the smoky, greasy, damage-causing substances and the potentially harmful pollutants that are caused by cooking, and make your kitchen area a much cleaner and clearer environment.

How to Choose the Proper Kitchen Range Hood

Now that you have an idea on what is kitchen ventilation and what are the types of hoods and fans that can help in maintaining proper air circulation in your kitchen, it is important that you have knowledge on how to choose the right kitchen range hood for you. Therefore, in order to help you, here is a list of factors you should consider when buying your own range hood: 

  • CFM or Air Flow Strength

One of the most important considerations when buying your own range hood is the cubic Feet per Minute (cfm) which is a measure of the volume of air being exhausted through the range hood. In simpler terms, this measures the capacity of  the range hood to remove unwanted odor, smoke, and other debris in the kitchen. Moreover, this measurement is always based on when the hood is running at full speed and at zero pressure. This may be relatively reduced depending on the range hood’s distance to the outside, the type and number of bends, and the resistance of the blow-back damper and wall plate.  The cfm requirement will significantly depend on the type and output of your range top, the size of the hood, the positioning of the hood, plus the length and configuration of your ductwork.

For electric tops, you need a range hood output between 150 cfm to 300 cfm because an electric cooktop is low powered. If you are using an electric deep fat fryer, then it is considered to be a gas stove top and not an electric top, hence it will need a different specific cfm for your range hood to maximally clean the air during cooking. 

For gas stove tops, you need to calculate your required cfm depending on the british thermal units (btu) found specifically in your gas cooktops. With that, calculate your cooktop’s btu rating by adding the power of each burner and then divide the total by 100. For approximation purposes, regular gas cooktops usually have outputs of up to around 40,000 btu [British Thermal Units]. Applying the formula, the regular gas stove tops will require about 400 cfm range hood.

  • Blower Types

Range hoods may come with either a centrifugal squirrel cage blower or an air-ring fan. These two have differences in function and effectiveness. On one hand, the centrifugal blower is more efficient and delivers more CFM. It is also less noisy. However, this type is usually more costly compared to its counterpart. On the other hand, the air-ring fan, also known as fan blade or rotary fan, discharges air horizontally and is noisier. It may be cheaper than the centrifugal blower, however it is less efficient in maintaining proper ventilation in the kitchen. 

  • Size

Other than a sufficient CFM, adequate coverage over the range top in order to trap smoke, steam, and grease is an important factor to maintain proper ventilation. Hence, it is important to consider the size for aesthetic and functional reasons. It is good to note that range hoods are actually made somewhat smaller in width than stated so that they would fit a standard space. Moreover, it is important to remember these things:

  • Height from Range Top

The rule is the lower the range hood is, the better is its performance. This is especially important for low cfm hoods. For electric cooktops, a height of 18” and up is fine. Placing it lower than that recommended height will make it hard for you to manipulate your pots during cooking. For gas stove tops under 40,000 btu, 20” is usually the recommended height. However, you can go up until 24”. It is also important to note that the higher the range hood is from the range top, the less effective it will be, so it is important to compensate for extra height by increasing CFM and/or its size or coverage.

  • Width 

It is recommended to leave a space for your vent hood at least 3” wider on each side between your wall cabinet layout. This extra width will make sure that there is enough space to carry off much more of the smoke and unwanted particulate matter, while making sure there is good kitchen ventilation. 

  • Depth

Most countertops are 25” deep. Hence, under-cabinet and wall mounted kitchen range hoods come in depths about 20”, 22”, 24”, and 27”. For electric and low output gas tops, a range hood 20” deep is essentially enough, especially if they are only 18” to 20” above the range top.

  • Filters and Grease Traps

These are also things you need to consider when buying a range hood. They come in different forms and have varied effectiveness in clearing unwanted smog and matter in the kitchen. 

Filters are often made of charcoal and their primary purpose is to absorb cooking odor. Depending on the amount of cooking you do, they might need changing, frequently or less so. Moreover, you can observe filters for hoods that are not vented outside.

Grease traps, as it name states, are utilized in order to catch the grease that is suspended in air rising from your cooktop during meal preparation. There are three types of  grease traps which include Mesh, Baffle and Cup. Aluminum or stainless steel MESH traps are the most common type of filters. However, they need frequent cleaning in order to prevent clogging that can cause a reduction in airflow. Hence, careful handling during frequent cleaning is a must so as to prevent damaging them. Baffle filter traps are often more effective in ventilation because they trap more grease while making sure there is no blockage of air or reduction of airflow. They are also rigid and will hold their appearance indefinitely. Just like aluminum steel, they need frequent cleaning too. A Cup trap is only available to some models. It has an unusual way of trapping grease similar to a tray under a barbeque. 

Because the kitchen is indeed the center of the home, it is only vital that it is clear from unhealthy air pollutants produced during cooking due to heating oil, fat and other food ingredients. Exposure to pollutants such as carbon monoxide, nitric oxide, and particulate matter can produce or worsen a wide range of health problems. However, this risk can be reduced through having proper kitchen ventilation. This can be achieved choosing the right range hood. A system that keeps the air in your cooking space free from lingering odors, smoke and other health concerning pollutants. With the amount of options of vent hood styles currently available and almost no limitation on the placement or style of hood, there is truly something that can satisfy everyone’s tastes, even yours. More importantly, other than maintaining proper air circulation in your kitchen, a kitchen ventilation system can help maintain a comfortable and healthy atmosphere throughout the rest of your home. 

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