Are you trying to find ventilation fans among various brands on the market but aren’t sure where to begin? To assist you in finding the right one, we’ve put together a list of the 7 best to help you pick the perfect one!
We investigated and evaluated a number of the top-selling ventilation fans on the market in order to create our list of the best. Making a decision among the many options available is never simple. There are an infinite number of models available, each with a distinct price. And as you’ll find out, the best options aren’t usually the ones you imagine! This comparison is rich and relevant because of the numerous factors that were employed. You will find products featured in this ranking not only based on their pricing but also on their features and other customers reviews. To write this review, we completed 29 hours of research and did 87 ventilation fans tests. You won’t need to pick products at random any more. If you’re unsure of what to look for, browse our list and consult the buying guide!
An overview of our top picks
Table of contents
The best ventilation fans you can buy today
- Powerful Airflow: This VIVOSUN powerful blower with a fan speed of 2500 RPM can create an airflow of 195 CFM; It works efficiently in ventilating grow tents, transferring heat or cool rooms, circulating fresh air, as well as controlling proper humidity, temperature, and air quality for your grow area
- Quiet Operation: Fitted with a flow deflector that concentrates the fan stream and cuts turbulent kinetic energy to reduce sound output to just 30 dB, which does not have any harm to your health and will not disturb your work
- Safety Protection: The motor is ETL listed and features an automatic reset function to prevent overheating or other safety issues; The electrical junction box is made from flame-retardant components for fireproofing
- Simple Hookup: The flanges on both the intake and exhaust ends are simple to assemble with the vent hose by locking tabs; A cord of 5.9-feet long for hassle-free setup; The housing, even the impeller and blades, are easy to detach for cleaning and maintenance
- Wide Applications: It can improve airflow to reduce humidity, block odors, and lower temperatures in grow rooms, basements, or kitchens
- Designed for projects that requires cooling or ventilation; or as a replacement fan for various products.
- Includes a heavy-duty aluminum fan with power plug cord, two fan guards, and mounting screw set..
- UL-certified fan with dual-ball bearings has a lifespan of 67,000 hours. Can be mounted in any direction.
- 120 x 120 x 25 mm (4.7 x 4.7 x 1 in.) | 100 to 120V AC | Airflow: 51 CFM | Noise: 30 dBA | Speed: 1800 RPM
- Designed for projects that requires cooling or ventilation; or as a replacement fan for various products.
- Includes a heavy-duty aluminum fan with power plug cord, two fan guards, and mounting screw set.
- UL-certified fan with dual-ball bearings has a lifespan of 67,000 hours. Can be mounted in any direction.
- High Speed: This model is designed to maximize airflow and can be too loud for some applications.
- 120 x 120 x 38 mm (4.7 x 4.7 x 1.5 in.) | 100 to 120V AC | Airflow: 110 CFM | Noise: 47 dBA | Speed: 2600 RPM
- Noted: There are no any Button Control for our products.
- 【Stable & Durable Exhaust Fan】: The ventilation fan is made of high-quality metal materials, with a bright surface, anti-corrosion, anti-scratch and prevent inhalation of foreign objects. Compared with other competitors' products, it can withstand moisture and high temperature, provide a stable working environment for the ventilation fan, and longer life of the ventilation fan.
- 【EFFICIENT VENTILATION FAN】 - Adopts double ball bearing outer rotor brush-less motor to ensure high efficient, quiet operation and high-quality performance. Compared with ordinary motors, the upgraded motor can reduce friction coefficient, save electricity effectively and enlarge the service life of the machine.
- 【EASY TO INSTALL】- Suitable for wall or ceiling installation. The exhaust fan is recommended to fix with glue or screws.Convenient to clean, you can remove the motor by unscrewing the four-corner screws. The detachable design is convenient for cleaning up fragment or greasy dirt regularly for increasing service life.
- 【Widely used wall ceiling ventilation fan】It is an ideal choice for creating efficient indoor HVAC system among workshops, basements, warehouses, apartment, kitchen, bathroom and other areas that require continuous or regular ventilation.High power bathroom exhaust fan can remove exhaust gas and ventilation with quickly and quiet way.
- 【100% after-sales service】For All customers, this product comes with Lifelong Technical Support & 24 hours Premium Service. If you have any issues about the ventilation fan, please contact us first, we will give you the satisfied solution as soon as possible.
- Durable: The fan has a strong motor which features a permanently lubricated bearing that operates quietly and requires no maintenance
- Compact But Efficient: This duct fan is compact and lightweight enough to be installed in areas with little available space; With a diameter of 6 inches, speed of 2960 RPM and 240 CFM air flow
- Low Noise: Superior balanced centrifugal impeller for long service life & quiet operation; A less than 37 dB noise level does not have any harm and will not disturb your work
- Wide Applications: You can have it in bathrooms, kitchens, workshops, basements, attics and etc, in order to boost airflow in HVAC systems; Also, it can be used in grow rooms as intake fans or exhaust fan
- Specifications: Voltage 110/120V, Power 37W; Max Operating Temp of Motor is 130℃ / 266℉; Max Ambient Temp is 60℃ / 140℉; Note: Please turn the fan off immediately if the blades get stuck by other objects
- APPLICATIONS: This 12 inch shutter/exhaust fan with automatic Shutters can help replace your ac unit by cooling your garage, attic, greenhouse shop or chicken coop.
- INSTALLATION: Can easily be added to a window opening or opening in the wall along with a thermostat to optimize cooling.
- COOLING AND VENTILATION: This industrial grade shutter fan can solve all of your cooling and ventilation needs.
- RUST PROOF ALUMINUM SHUTTERS: This shutter fan is made with corrosion resistant aluminum shutters and blades. This provides longevity to the fan and will prevent any rust from forming.
- 120 Volts, 63W, 0.52A,1750 rpm, 11M/S, 1800CFM, the black wire of the fan is connected to switch ,the White wire of the fan is connected to Neutral and green wire to ground.
- 【Ventilation fan with Check Valve and slim design 】 This 4” air duct vent has check valve. You can keep air reversible or exhausting cooking odors by your request. When the airflow stops, it can be closed by spring automatically. And if you don’t need the check valve, you can take it off easily.
- 【Wall exhausted fan with filter】 When installed on glass, window or wall, it can be used to prevent dust, leaves, with ABS panel filter, providing you a clean air circulation environment.
- 【Easy to install】--This wall-mounted vent fan can be installed on a window or wall and is easy to install. It is an advanced window exhaust fan and wall exhaust fan with powerful motor and high performance.
- 【High Performance】--12W low energy consumption, noise lower than 35 dB. Also designed with back damper check valve which allows it open and close automatically with the fan.
- 【Widely Used】--Extractor fan comes with a power cord with plug,perfect for greenhouse, attic, bathroom, kitchen, windows, basement, garage, office, living room and other places that need ventilation.
- ☢️【Exhaust Fan with Super Motor】- The attic fan adopts double ball bearing outer rotor brushless motor to ensure high efficient, quiet operation and high-quality performance. Compared with ordinary motors, the upgraded motor can reduce friction coefficient, save electricity effectively and enlarge the service life of the machine.
- ☢️【Efficient Ventilation】-6 Inch wall-mounted vent fan works quietly to move more air. You get maximum ventilation with improved performance not found in others. Exhaust fan tailpipe diameter is 6"/150mm, Voltage: 110 VAC, Power: 38 W, Air Volume: 308 CFM, Rotation Speed 2800 r/min, Frequency, 60HZ. Noise is about 55dB, Plug cord length about 4 Ft.
- ☢️【Discretionary Control】-Do you want to achieve different airflow speeds at any time to achieve better ventilation while still in control? Our Through Wall Fan can be controlled through a manual knob. You can adjust the speed to meet the ventilation needs of different environments. What are you waiting for? Let it be!
- ☢️【Easy to install】--The bathroom exhaust fan has four holes. It can be used by turning the screws on the selected wall, fast and convenient installation, and easy to maintain. It is friendly for anyone to install with no experience. The detachable design is convenient for cleaning up fragment or greasy dirt regularly for increasing service life.
- ☢️【Widely Used】--Ventilator extractor fan comes with a power cord and own Variable Speed Controller, perfect for greenhouse, attic, bathroom, kitchen, windows, basement, garage, office, living room and other places that need ventilation.
- 1/3hp with 9 blade high pressure fan wheel
- 1000cfm air flow
- 25ft ducting hoses with canister
- Can do both extract and suction work
- Rotationally molded Housing
- 12 Inch Utility Blower Extractor Fan: Color: Orange, Power: 520W, Frequency: 50 / 60 Hz, Material: Steel, Motor Speed: 2800 RPM, Air Flow: 2295 CFM / 3900 m³/h, Fan Diameter: 12 inch / 300 mm, Duct Expands Length: 32 ft / 9.8 m, Duct Thickness: 0.012 inch / 0.3 mm, Axial Fan Bearing Type: Ball Bearing, Noise: 69 dB(A), Static Pressure: 385 Pa, Current: 4.622A, Fan Dimensions(L x W x H): 13.7 x 14.8 x 15.8 inch / 348 x 376 x 401 mm, Net Weight: 36.38 lbs / 16.5 kg.
- 520W Pure Copper Motor: This portable ventilation fan is designed with a high-velocity, high-volume output, 100% copper winding motor. 2800 RPM motor speed is suitable for long-term ventilation. It can move a large amount of air quickly with low noise of 69 dB (A).
- 2295 CFM Large Air Flow: The large air volume of 2295 CFM / 3900 m³/h and 7 metal blades provides fast and effective ventilation, extracts the maximum air, and maintains high-efficiency work. Besides, 2 high-density covers to ensure portable ventilators work continuously and safely.
- 32 FT Flexible PVC Ducting: This PVC ducting applies hard-wearing, flexible vinyl woven polyester with carbon wire spring and adhesive tape, smooth inside wall to be water-proof. Duct Expands Length: 32 ft / 9.8 m. Adjustable ropes and D-shaped rings are set for hanging the PVC flexible duct freely.
- Sturdy & Humanized Design: The heavy-duty cylinder fan is equipped with a durable steel casing, bringing excellent durability and extending its service life. Two handles and four rubber feet allow you to use and carry effortlessly. Ideal for factories, basements, shipyards, farms, grain storage, warehouse, kitchen, office, workshops, tobacco, tunnel, automobile manufacturing, and more places requiring ventilation.
- 12'' Exhaust Fan: Dimensions: 15 x 15 inch, Airflow: 1000 CFM, FCC Listed, Speed: 1600 rpm. Our high-airflow exhaust fan can eliminate heat, humidity, unpleasant odor, and dust from rooms, buildings, and small enclosed work areas. Get ready to relax and in clean air in all your rooms.
- High Performance: 120V/60Hz, 72 W. The wall exhaust fan has a premium motor that maximizes airflow while reducing noise and power consumption. And the fully enclosed motor has thermal protection and permanent lubrication for security and easy maintenance.
- Rust-proof Material: The shutter exhaust fan has a rugged all-metal structure and features a galvanized steel frame, aluminum alloy fan, and shutter, which is highly resistant to weather, liquid, and dust.
- No Assembly Required: Get ready to fly through the installation process! Our wall mount exhaust fan comes fully assembled and can be easily added to window openings or openings along walls to optimize cooling.
- Widely Used: It is perfectly suitable for any place you install and stays with you through the long, sultry summer! Works well for garages, workshops, chicken coops, sheds, attics, greenhouses, etc.
- 【Energy-Efficient Ventilation】This powerful inline duct fan speed of 3300 RPM can create the air flow of 345 CFM, Maximum power consumption is only 19.2W. Upgrade DC motor & low noise effectively circulating air, quickly move vast amount of air to exhaust odors.
- 【Application Scenarios】The 6 inch booster duct fan designed to quietly ventilate grow rooms, bathrooms, kitchens, workshops, basements, attics and etc, in order to boost airflow in HVAC systems.
- 【Easy to Install】Hon&Guan air exhaust fan's blade and the body are made of high quality plastic, for quick removal and easy maintenance.
- 【Adjustable Controller】 The 6-inch duct fan includes a variable speed controller, which can allows you to adjust the airflow and noise at will.
- 【Excellent Performance】Duct size: 6” | Dimensions: 7.28 x 5.79 x 5.79 in. | Voltage: 100-240V| Air Presssure: 142 Pa| Noise: 32 dBA
- POWERFUL AIR VENTILATOR - 960 CFM, 115V, 0.6A, 1/20 Horse Power, 1650 RPM, Coverage up to 1400 square feet. Industrial ventilation fan with shutter. 12 Inch Variable Speed Shutter Exhaust Fan with automatic shutters
- SPEED AND THERMAL CONTROL - Variable speed and temperature regulation control, comes with Variable speeds and thermal control features of newest Thermospeed(TM) Controller ILG8SFST, temperature control range 32 - 130F
- BUILD TO LAST - Industrial grade galvanized steel frame with aluminum shutters and fan blades, reliable direct drive motor, Variable speed, UL certified, Noise Level < 65dB. Ideal for warehouse, garage, greenhouse, workshop exhaust and dust extraction. Corrosion-resistant with OSHA compliant wire guards. UL Listed with speed controllable, permanently lubricated motor
- EFFICIENT - 12 inches steel blades with deep pitch angle for maximum air movement, exchange air at 960 cubic feet per minutes. Mounting type: Wall Mount
- CUSTOMER SUPPORT - Local customer support to address all questions and concerns. Product is UL/cUL Listed.
- 10'' Shutter Exhaust Fan: Dimensions: 12.8 x 12.8 inch, Airflow: 820 CFM, ETL Listed, Speed: 1650 rpm. Our high-airflow exhaust fan can eliminate heat, humidity, unpleasant odor, and dust from rooms, buildings, and small enclosed work areas. Get ready to relax and in clean air in all your rooms.
- High Performance: 120V/60Hz, 15W. The wall mount exhaust fan has a premium EC motor that maximizes airflow while reducing noise and power consumption. And the fully enclosed motor has thermal protection and permanent lubrication for security and easy maintenance.
- Smart Programming: We are equipped with an intelligent controller! Not only do you have temperature and humidity triggers, but it also allows you to set up to 10 speeds that will respond to changes in them. You won't miss a thing and will always be ready to adapt! There are multiple modes, allowing you to adjust as you wish. Timer and alarm modes are available on demand.
- Rust-proof Material: The exhaust fan has a rugged all-metal structure and features a powder-coated steel frame, aluminum alloy fan, and shutter, which is highly resistant to weather, liquid, and dust. It is perfectly suitable for any place you install and stays with you through the long, sultry summer!
- Plug and Play: Get ready to fly through the installation process! Our wall exhaust fan comes fully assembled and ready to install right out of the box. Includes 4 bolts. You're ready to go by connecting the 6.2 ft power cord. No more worrying about wiring! Works well for garages, workshops, chicken coops, windows, attics, greenhouses, etc.
- VERSATILE FAN: Ventilation fan helps eliminate , tobacco smoke, and cooking odors and can be installed in either the ceiling or wall
- EFFICIENT: Operates on 70 CFM and has a 6.0 Sone rating to ensure a peaceful surrounding when in operation
- EASY INSTALLATION: Torsion springs grille mounting - no tools necessary for a quick and easy installation. Compact housing fits easily between ceiling joists or wall studs. Our instillation guide is located above the reviews on this page.
- DECORATIVE: Paintable polymeric grilles allow you to ensure the fan is cohesive with your existing decor
- FEATURES: Plug-in, permanently lubricated motor with the Broan-designed polymeric blower wheel for high-quality operation every time
- DIMENSIONS: Grill length is 9". Grill width is 9.25". Housing dimensions are 7-1/4" x 7-1/2" x 3-5/8"
- If you are purchasing this item in Vermont, Washington, Colorado, Washington DC, Oregon, Massachusetts, Rhode Island, or New York we recommend Broan-NuTune AE80B per state requirments.
- 70 CFM and 3.5-Sones
- Powerful centrifugal blower wheel
- Wall and ceiling mount
- Compact housing fits easily between ceiling joists or wall studs
- Backed by 1-year limited manufacturer's warranty
- Low noise and dual ball bearing: each fan is engineered to be ultra quiet while delivering high airflow. Dual-ball bearings have a long lifespan.
- 3 speed adjustable: features a multi-speed controller, you can adjust the fan speed easily, optimal it to suitable airflow levels. Maximum speed is 1500 RPM.
- Multiple protection: have metal grille on both sides, protect your hands and plants when the USB fan is working. Square design allows the fans to be laid flat or stand upright.
- Dimensions: 4.72 x 4.72 x 1.77 inch, air flow: 50 CFM, noise: 19 dB. No adapter included.
- Multifunctional USB fan: can installed on a plant stand rack or plant shelf, keep your plants cool and circulate the air. Also perfect for receiver DVR playstation TV box computer cabinet cooling.
- 🍃【Crawlspace&Basement&Garage&Attic Ventilation Fan】Airflow: 260CFM, Ventilation type: Air out. With this exhaust fan, you can exchange the outdoor and indoor air, improve room air quality and balance the humidity. Use crawl space vent fan to change your crawl space from low-speed passive ventilation to efficient active ventilation.
- 🍃【Built-in Dehumidistat & Freeze Protection Thermostat】Operating humidity: 5%-80%RH, this High-Flow Powered Ventilator Fan will turn ON/OFF automatically with SET humidity % level. Auto stop working when the outdoor temperature is lower than 35°F/3°C. This vent fan will help reduce moisture in crawl space / foundation / basement to protect the structure of the house and the health of its occupants.
- 🍃【Built-in Isolation Mesh & IP-55 Rated】5.5mm Isolation Mesh prevents reptiles from gaining access to the crawl space; Solid-Built Aluminum Zinc Shell with IP-55 rating, highly resistant to liquids and dust, higher weather-proof, makes it ideal for work in a humid environment with a long service life, don't worry it rust. Maintenance free crawlspace fan helps increase air circulation to protect damp areas from condensation and wood rot.
- 🍃【Easy to Install & Operate Vent Fan】Overall Size: 13.4"x2.5"x 9.1", 6.7 inch fan with 6 foot grounded power cord. Faceplate can be trimmed to meet your different installation needs. Features simply knob control panel, easy to set humidity for running. Just plug it in, set it and forget it. Constant operation helps vent radon gas, treated wood gases and unpleasant odors, prevents seeping into living space.
- 🍃【Quality Service and Warranty, Buy Worry-free】Abestorm crawlspace ventilation fan is fully compliant with electrical safety ETL. Every Abestorm crawl space fan comes with a 2-year warranty. Moreover, we established a professional technical support communication center. You can call us directly, ready to assist you.
- IMPORTANT: All models are equipped with factory pre-installed thermostats to prevent fan operation when outdoor temperatures fall below 35°F.
- APPLICATIONS: This 7 inch shutter/exhaust fan with automatic Shutters can help replace your ac unit by cooling your garage, attic, greenhouse shop or chicken coop.
- INSTALLATION: Can easily be added to a window opening or opening in the wall along with a thermostat to optimize cooling.
- COOLIN AND GVENTILATION: This industrial grade shutter fan can solve all of your cooling and ventilation needs.
- RUST PROOF ALUMINUM SHUTTERS: This shutter fan is made with corrosion resistant aluminum shutters and blades. This provides longevity to the fan and will prevent any rust from forming.
- 115 Volts, 60Hz, 28W, 1680RPM, 760CFM
- Quiet Register Booster Fan: A quiet fan system designed for improving wall and floor vents airflow from HVAC systems to increase home comfort.
- Eliminate Uneven Room Temperatures: Biowind smart register vent equipped with programmable LED controller and high-precision temp sensor to work with HVAC. It can automatically turn on/off vent fan to heat or cool the rooms at the right time.
- New Upgraded Remote Control: Remotely adjust the fan speed(0-10 level）to meet user different needs and make a perfect balance between noise and comfort. No need to get up, More convenient.
- Energy-Saving & Cost-Effective: This vent booster fans are more energy-efficient to traditional AC and cooling devices. They rely on airflow to improve indoor temperature and circulation, maximize the heating or cooling from your HVAC system with minimum energy. Besides, This smart register vent continues running after HVAC system off, pulling every bit of heat or cold air into your home. Help you save more energy & electricity costs.
- Compact & Easy to Install: Biowind smart register booster fan is small in size and easy to move or install,making them convenient to use. Fits ONLY 4" x 10" Register Vent| Rated power: 6W | AC Input: 100 to 240 VAC| Airflow: 120 CFM | Noise: 18 Dba | Includes Wall Adapter, plug and play.
- Affordable: Compared to large-scale air conditioning and cooling devices, booster fans are relatively inexpensive and affordable, making them accessible to ordinary households.
- 12-inch portable blower/exhaust axial hose fan with 25-foot hose
- Provides directional airflow (2900 CFM) to limited access areas
- Perfect for crawl spaces, attics and basements
- 1-speed 120V enclosed motor Noise 70db
- Heavy duty orange coated steel constuction and comes with a 6-foot cord
How to choose a good ventilation fans
Does the idea of finding a fantastic ventilation fans make you anxious? When it comes to purchasing this product, specifically when deciding which model to select, has your head been spinning between options? You are not alone if that is the case. We are aware of the pressure involved in the purchasing process!
Your presence here indicates that you are interested in ventilation fans. Before choosing which product would be the best for your needs after being inundated with information, locate a reliable source with genuine selections. You can get that information from a variety of sources, including buying guides and rating websites, word-of-mouth recommendations from friends and family, online discussion forums where users can share their own experiences, product reviews that can be found all over the internet, and YouTube channels. You can only get the right product through exhaustive analysis. But you realize that’s not always simple. In order to ease your concerns, we have taken the time to develop a list of the top ventilation fans products available right now. You might be wondering how we came up with the list. How was this buying guide developed?
First, we used our algorithms to gather as much reliable data as we could about these products. To verify all the data gathered, we used both artificial intelligence and a lot of algorithms.
Then, our experts used criteria that are recognized in the business to evaluate them according to their quality to price ratio, allowing us to choose the top ventilation fans on the market right now!
The selection of the goods is not arbitrary. Before creating a list, we take into account a number of factors. Below are some of the criteria discussed:
Brand Value: What happens if you choose a dubious brand just because it appears to be a good deal? So the likelihood of receiving a product with a short shelf life increases. That is due to the fact that well-known brands have a reputation to uphold, while others do not. Top ventilation fans brands strive to provide some distinctive traits that set them apart from the competition. So, hopefully one or more of the items on our list will be perfect for you.
Features: Useful features are all you need, not tons of them. We consider the important aspects and select the top ventilation fans based on those.
Specifications: Numbers always help you measure the quality of a product in a quantitative way. We try to find products with higher specifications, but with the right balance.
Quality: A product’s quality may always be quantified with the aid of numbers. We look for goods with better standards that strike the proper balance. The best quality product that gets highly appreciated and recommended by experienced users.
Customer ratings: Would it be accurate to suggest that the ventilation fans were used by hundreds of customers before you? Superior ratings indicate that many customers had better service.
Customer Reviews: Like ratings, provide you with accurate and reliable information about the product from genuine customers. Customer ratings are very important to all of us because they contain accurate and reliable information about the customer service we received from several hundred customers.
Seller Rank: This is very intriguing! Not only do you need a good ventilation fans, you also need a product with rising sales that is trendy. It accomplishes two goals. First, the expanding user base proves the quality of the product. Second, given that number, producers must be able to offer greater quality and after-sales support.
Value: You get what you pay for, they say, so consider the value. Cheap isn’t always good and expensive isn’t always bad. However, that does not imply that spending a lot of money on a product that is flashy but underwhelming is a good idea. Before adding them to the list, we make an effort to evaluate how much value you can get for your money from your ventilation fans.
Durability: Durability and reliability are closely related concepts. You will benefit from a strong and long-lasting ventilation fans for months and years to come.
Product availability: Products come and go, and new ones replace the old ones. Most likely, a few new features and required changes were made. What use is it to use a supposedly good product if the maker no longer supports it? We make an effort to highlight products that are current and offered by one or more trustworthy sellers, if not more.
Negative Reviews: Yes, we do take that into account as well! The goods with the majority of bad reviews are filtered out and disregarded when we choose the best-rated one on the market.
These are the standards by which we selected our ventilation fans. Do we end our process there? Hell no. The most crucial fact about us that you should be aware of is that we regularly update our website with current and pertinent information. We have one more layer of filtration since we place the greatest importance on reader satisfaction. Please let us know if any product included here is incorrect, irrelevant, subpar, or simply out of date. We always value your opinions, and we’ll work hard to make any necessary corrections to our list in response to them.
Why should you believe us?
There are now thousands of possibilities for these products on Amazon, but choosing the best one can be difficult and time-consuming. And what ventilation fans should you purchase in 2022?
This guide is the result of more than 10 years of experience in researching, testing and writing about many topics. Each member of our team is an authority in their area. We read every article we could find online and every consumer review on every retail website for seven hours. Additionally, we discovered a ton of websites that offered helpful resources, including buying tips and thorough information on ventilation fans.
