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Bathroom and kitchen fans both serve to extract the air in the rooms in which they are installed. Generally, they remove moisture from your house. In the case of kitchen fans, they also help to remove odors, oil, and other contaminants or fumes that are turned airborne by the heat of cooking.
Given that these fans serve some of the same functions, you may be wondering if you can use a bathroom fan in the kitchen?
A bathroom fan cannot replace the function of a range hood. The extractor fans that are installed above kitchen ranges must be rated for that purpose because they need to be able to handle high heat and grease, two things bathroom fans aren’t designed to deal with.
Range hoods also help clear any Co2 that is produced if you have a gas stove. They can also remove hot air to keep your home cooler when using the stovetop or oven during the summer months.
However, you can use a range hood, which most kitchens in North America have installed, in combination with a bathroom fan to help remove moisture and odor.
Range hoods are absolutely a necessary part of any modern kitchen. There are many reasons why it should be installed if you are a regular cooker.
For either of these fans to be effective, they need to be vented, meaning they have to be attached to a duct that leads outside of your home.
A range hood is the metal structure above a cooktop that has a fan and usually a light in it. It needs to be ducted to the outside, or else you are just sucking all that grease and other pollutants into your ceiling.
A downdraft exhaust is a vent that is installed beside the cooktop to suck air across the top of the stove and down, it is less effective than a range hood but works well enough for kitchens that cannot accommodate a range hood.
Ventilation may seem like an easy operation, but it is far more complicated than most of us think.
You now know you need a more powerful fan in the kitchen, but there are other considerations besides removing the harmful polluted air. Something has to replace the air that is being removed. This new air might be pulled back in through your furnace, water heater, or other appliance’s exhausts if you live in a modern airtight home.
Pulling air in from the appliance exhaust pipes can bring poisonous carbon monoxide and other by-products of combustion into your home, a process known as back-drafting. If you have a powerful enough fan, it may be able to pull in enough air from these appliance exhausts to lead to carbon monoxide poisoning.
To help you ventilate your home correctly and avoid filling it with dangerous airborne poisons, we have put together this primer on kitchen and bathroom fans to help you keep your home, cool, humidity controlled, and free from harmful pollutants.
The Difference Between the Two
Bathroom fans have much lower CFM (Airflow) and generally are much quieter compared to range hoods.
Kitchen fans, on the other hand, are close to heat, grease, and other pollutants. Thus, they must be built using materials that can withstand the heat. They also need more power so that they can remove air at quicker rates. This allows them to capture more harmful particles and fumes before they spread around the kitchen and helps them cycle all the air in the kitchen faster to remove any that escaped the fan initially.
The ductwork that vents the fan is also different for kitchen extractors. Again, they have to deal with things like grease, which get deposited along the inside of the ductwork as the air cools.
These grease deposits are also why you should clean your kitchen fan/range hood once a month, or more if you cook with a lot of fat like oil and butter.
You need to clean your ducts regularly as well, the regularity depends on how often you cook, but they should be cleaned about once a year for moderately used ranges. Although the risk is low, ducts filled with grease are a potential fire hazard. Keep in mind that cleaning the ducts should be left to the professionals.
Why You Need Extractor Fans
Extractor fans help to remove moisture and unwanted odors from your home. In the case of kitchen extractor fans, they also help to remove grease and pollutants from the air, that would otherwise be deposited on surfaces around the kitchen.
Excess moisture in your home can lead to mildew and mold, which is not only bad for the structure of your home but also for your health. Even worse, mold will often start in areas you can’t initially see, such as attics, basements, ducting, and behind drywall.
Excess Moisture & Your House
Mold is not usually a cause of structural damage to homes; however, the same excess moisture that allows mold to grow can lead to significant rot in essential structures of your home. Crawlspaces, floor joists, girders, and sill plates are all susceptible to rot from excess moisture. Repairing issues with any of these are going to be expensive and can be avoided by using extractor fans to draw excess humidity from your home.
Mold & Your Health
Living in conditions of dampness and the presence of mold has been linked to respiratory illnesses in the nose, throat, and lungs. Symptoms include coughing, wheezing, headache, fatigue, and irritation of the skin, eyes, or throat. The Environmental Protection Agency has dubbed this “sick building syndrome.” Mold exposure has also been shown to increase the symptoms in those who suffer from allergies and asthma.
Regular mold exposure may also contribute to the risk of bronchitis and respiratory infections.
For more information on mold and your health, read poison.org’s article.
What to Look for in Bathroom Fans
If you are looking to replace your bathroom fan, there are a few considerations to keep in mind when checking out the options online or at your local hardware or home improvement store.
Keep in mind:
Bathroom fans should be installed close to showers and tubs to remove humidity as it rises into the air in the form of water vapor.
Now, let’s review a few primary considerations when purchasing a new bathroom extractor fan.
Consider the Fan Capacity
Your fan needs to be powerful enough to replace the air in your bathroom quickly. The Home Ventilating Institute recommends that your bathroom fan should replace the air in your bathroom eight times per hour.
The power of a fan is typically measured in cubic feet per minute (CFM). I wrote an article on how are bathroom fans rated, where I explain what that means in more detail.
If you have a bathroom that is less than 50 square feet, The Home Ventilating Institute recommends a 50 CFM fan. For bathrooms that range from 50 to 100 sq. feet, you can simply use a one-to-one conversion meaning a 60 square foot bathroom would need a 60 CFM fan and 85 sq. foot bathroom requires an 85 CFM fan.
If your bathroom is over 100 sq. feet, then use the same conversion as above but add 50 CFM for every bathtub, shower, and toilet. If you have a bathtub with jets, tack on another 100 CFM.
Consider Noise Level
This is especially important if anyone in your home likes to enjoy a relaxing bath. You don’t want a noisy fan disturbing your relaxation time.
You can find a Sone to Decibel calculator here
A bathroom fan’s noise level is measured in sones. 4 sones is about equal to a standard TV volume. Your refrigerator is around 1 sone, which is right about where you want your bathroom fan to be if you are looking for quiet ventilation. Check out my other article about sone ratings if you would like to learn more.
Consider Design & Added Features
With the multitude of extractor fan designs, you can be sure that you will find something to suit any décor, so make sure you’ve got an idea of what you are looking for before you start looking.
You can also get added features like lights, speakers, and heating elements. Two other useful features include timers and humidity sensors, which can automatically switch off your fan, helping you conserve energy. I personally use a humidity sensor since this will automatically keep humidity levels within a normal range, And it is very convenient.
An appropriately powered fan will effectively protect your home from moisture damage and mold by effectively removing humid air.
What to Look for in Kitchen Fans
Kitchen fans are stronger than bathroom fans as they have to move air quickly so that grease and other pollutants that result from cooking don’t have time to circulate throughout your house.
If you have ever cooked bacon or other dishes that produce a lot of odor, and then left your home only to return hours later to the smell of that meal you cooked, then you know why you want a powerful enough kitchen fan to remove those nasty smells that are thrown into the air when you cook.
Consider Where the Fan is Mounted
There are a lot of factors that will determine how powerful your fan needs to be. If it is mounted in a range hood directly over the cooktop, you can get away with a lighter powered fan. However, it still needs to be significantly more powerful than a bathroom fan.
To compare, a 100 square foot bathroom (that’s a spacious bathroom) can use a 100 CFM fan, while the fan in a range hood needs to be a minimum of 250 CFM even in the smallest of kitchens with a small cooktop. A 100 CFM fan is on the higher range of bathroom extractors. Yet, the minimum power for a kitchen extractor is two and a half times that!
There are a few other factors about your home that can affect your kitchen extractor fan’s power requirement.
Consider Your Cooking Style
If you cook at high temperatures or with a lot of oil or butter, you need even more power because more grease will be present in the air. You want to remove these compounds before they can travel around your home and settle on walls, ceilings, floors, and other surfaces.
A fan’s capture efficiency determines its ability to remove the particles as they come off the cooktop. Unfortunately, there is currently no standard measurement of capture efficiency. Researchers at Lawrence Berkeley National Laboratory are developing such a system so that you will be able to make your choice on kitchen fan based on design, CFM, and capture efficiency.
Until then, you can improve your kitchen fan’s capture efficiency by:
- making sure the range hood covers all the burners; this will help funnel the fumes towards the fan in the hood.
- cooking on the back burners when possible, as this will allow the fumes to be better contained by the hood and fan.
Proper venting of the ducts will also help improve the fan’s capture efficiency.
Check the Ducting
The ducting can also change the type of fan you need. The ducting length, width, and the number of bends can all increase the required power. If you are not sure how to check the ducting of your kitchen fan, call a professional. Any contractor or builder should be able to come in and assess the situation.
They should also be able to discuss your ventilation needs and provide guidance on choosing the best option given your kitchen’s size and design.
To get an in-depth look at kitchen extractor fans, check out the Home Ventilating Institute’s pamphlet.
One last note on kitchen fans:
Recent studies have indicated that although most North American homes have a kitchen fan installed, less than 33% of people use them regularly. That fan is not going to do you any good if you don’t use it when you use your range. So, the next time you head into the kitchen to cook or even to boil the kettle, remember to turn on your kitchen fan so that it can do its job of keeping you and your home safe and comfortable!
Bathroom and kitchen fans both work to move air out of your home. Thus, replacement air has to enter from somewhere. This is an incredibly important consideration in modern homes that are far more airtight than older homes.
If your home does not provide for proper air intake, then the air pressure will be lowered, which creates a vacuum. This vacuum will begin to suck air into your home anyway it can. In modern homes, this usually means through the exhaust for appliances like your furnace or water heater. That will suck fumes from these appliances into your house instead of allowing them to escape through the exhaust ducting.
These fumes are a very serious problem. They contain harmful gases, especially carbon monoxide–a colorless, odorless, poisonous gas. Because you can’t see or smell it, it is easy for this gas to reach dangerous levels without you even knowing. If the levels get high enough, the result could be lifelong severe injuries, including brain damage. In extreme cases, it can and has lead to death.
Symptoms of carbon monoxide poisoning include:
- Dull headache
- Nausea or vomiting
- Shortness of breath
- Blurred vision
- Loss of consciousness
If this buildup of carbon monoxide occurs while you are asleep, you may never notice or experience these symptoms and won’t be able to leave your home, which will likely result in death. For more information on carbon monoxide poisoning, visit the CDC’s website.
Proper ventilation is an aspect of your home that you should take seriously.
Bathroom and kitchen fans, while serving similar purposes, have different requirements. Kitchen fans must have the ability to move more air as they not only need to remove water vapor but also volatile chemicals that are turned airborne from cooking. Kitchen fans can also help to keep your home free of odors that result from cooking. You should never use only a bathroom fan for ventilating your kitchen.
Proper ventilation in your home is necessary to keep mold, mildew, and moisture from accumulating in your home. All of these can contribute to health concerns for you or structural concerns for your home. To avoid medical problems and costly repairs to your home, make sure the fans you have in your bathroom and kitchen are powerful enough to cycle the air in the room in which they are installed.
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