In modern homes built tightly and well-insulated for energy efficiency, having proper ventilation is crucial to keeping the air fresh and comfortable.
Exhaust Fans are essential for achieving optimal ventilation in residential and professional buildings by removing stale air, moisture, and odors from indoor spaces like kitchens, bathrooms, garages, and warehouses.
Whether you want to improve air quality or prevent moisture-related damage, understanding how exhaust fans work and selecting the right one is essential. This guide covers everything you need to know, from the types of exhaust fans to installation tips and top brands.
- What Are Ventilation Exhaust Fans?
- Improving Air Quality with an Exhaust Fan
- Exhaust Fans vs. Supply Fans
- Types of Exhaust Fans
- How to Know if Your Home Needs an Exhaust Fan
- Selecting the Right Size Exhaust Fan
- Installing an Exhaust Fan
- Why Choose an Exhaust Fan?
What Are Exhaust Fans?
Exhaust fans are mechanical devices that pull stale air from indoor spaces and expel it outside. These fans are commonly used in bathrooms, kitchens, and laundry rooms to remove humidity, odors, and stale air and prevent mold and mildew.
However, these fans can also be used in commercial spaces like shops and warehouses and excel at removing heat and moisture at high speeds.
The way these fans work is fairly simple: using a traditional bladed fan or impeller, they pull room air and expel it through a window, vent, or duct to the home's exterior. This process removes pollutants and helps maintain a comfortable and odor-free environment.
Improving Air Quality with an Exhaust Fan
Exhaust fans significantly enhance indoor air quality by addressing three main issues:
Pollutant Removal
Exhaust fans effectively remove airborne particles, smoke, and odors, leaving the indoor air cleaner and more comfortable to breathe.
Humidity Control
By reducing moisture levels, these fans help prevent conditions that lead to mold growth, peeling paint, and warped wood.
Fresh Air Exchanges
More consistent fresh air exchanges help promote better respiratory health and comfort, especially in newer, tightly-built homes where stale air can build up and cause issues. Homeowners should be aware of local building regulations regarding the number of fresh air exchanges required for different spaces.
Exhaust Fans vs. Supply Fans
Exhaust and supply fans play essential roles in ventilation, but their functions differ. Exhaust fans remove air from a room and expel it outside, while supply fans bring fresh air into a building from the outdoors.
When deciding which fan to use, consider the goal:
- Exhaust fans: These fans are used to remove pollutants, moisture, and odors.Exhaust fans depressurize a space by expelling stale air and pulling fresh air in from vents and natural ventilation sources, like cracks, gaps, and holes.
- Supply fans: They are often used to increase fresh air intake, particularly in tightly sealed or energy-efficient homes. Supply fans pressurize a space, filling it with a constant air stream and expelling stale air through vents. Read more about supply fans here.
Each of these fan types has distinct advantages and disadvantages, and sometimes, the two fans are used together in a balanced system that introduces and exhausts an equal amount of indoor and outdoor air.
Types of Exhaust Fans
There are several different styles of exhaust fans that are used for different needs and situations. Picking the correct type of fan is incredibly important for solving your ventilation issues. See the exhaust fan styles and popular models below for more information about their applications.
Wall-Mounted Exhaust Fans
Wall-mounted fans, like shutter exhaust fans, are installed directly on an exterior wall, making them ideal for spaces without access to an attic or ceiling for ductwork. They vent air directly outside, offering a straightforward solution for ventilation without complex installation.
Shutter mount exhaust fans typically have a traditional bladed fan and shutters that automatically raise and lower as the fan operates. They also usually come in a range of sizes from 10 inches to larger than 36 inches.
See two styles of wall-mounted Exhaust Fans below:
- Shutter Exhaust Fan: Canarm 24-in XFS24 1/2 HP Two Speed Shutter Mounted Exhaust Fan
- Crawlspace Exhaust Fan: AC Infinity ââAIRTITAN T8 Crawlspace/Basement Exhaust Fan
Ducted Exhaust Fans
These fans are installed within ductwork, connecting the fan's intake to an external exhaust point. This option, like an inline duct fan or mixed-airflow inline duct fan, is often quieter than wall-mounted options since the motor can be farther away. Ducted fans are also versatile, as they can vent multiple areas simultaneously, making them an excellent choice for larger spaces.
Ducted exhaust fans sometimes have a specialty use, like venting radioactive radon gas, with radon mitigation fans.
See two styles of ducted exhaust fans below:
- Inline Duct Fan: Fantech FKD 8 XL 8in. Mixed Flow Inline Centrifugal Fan
- Radon Mitigation Fan: Suncourt Radon Fan Mitigation Kit
Ceiling Exhaust Fans
Specially designed for high-moisture environments, bathroom fans often include advanced features such as humidity sensors, which automatically turn on the fan when moisture levels rise, and motion detectors for energy efficiency. They are essential for preventing mold and mildew, particularly in smaller or poorly ventilated bathrooms.
Ceiling Exhaust Fans are also sometimes used in kitchens and laundry rooms.
See two styles of ceiling exhaust fans below:
- Bathroom Exhaust Fan: Broan RB Ultra Pro Series Energy Star Bathroom Exhaust Fan
- Roof Exhaust Fan: S&P LPD0-1AS Centrifugal Roof Sidewall Exhaust Fan
How to Know if Your Home Needs an Exhaust Fan
Poor ventilation can lead to many serious problems like excessive humidity, odors, and health risks. Signs that your home might benefit from an exhaust fan include:
- Consistent Condensation on Windows: If the inside of your windows consistently has condensation on them, that's a good visible sign that a space has high indoor humidity.
- Mold and Mildew Growth: Often, spaces like bathrooms are prone to high moisture and humidity due to their function, but when mold and mildew start growing, that's when you know there's probably a ventilation issue.
- Lingering Odors: Persistent lingering smells show that a space doesn't have adequate airflow.
Local building codes also play a role in ventilation. Many regions have minimum requirements for specific rooms, particularly bathrooms and kitchens. Compliance ensures safety, enhances property value, and may be necessary for resale.
For a more detailed analysis of a space's ventilation needs, users should consider hiring an HVAC specialist to identify issues and recommend solutions.
Selecting the Right Exhaust Fan
Selecting the right exhaust fan relies on a few critical factors, such as the fan's specific use, the airflow capacity (measured in cubic feet per minute), and the noise level produced by the fan.
We recommend consulting an HVAC professional to identify the correct type and size of fan for your space and needs. However, these guidelines provide a good approximation of the factors and metrics for these fans.
Understanding CFM
The airflow capacity of an exhaust fan is measured in CFM and represents the amount of air a fan can move in one minute. The larger the space, the higher the CFM needed. An HVAC professional can accurately calculate the CFM required for a specific space.
Air Changes Per Hour
Air changes per hour measure the number of times indoor air is replaced by fresh outdoor each hour. According to the EPA, most organizations recommend a system that can provide between 0.35 and 5 ACH for residential spaces.
Other Considerations
Rooms with higher ceilings or long duct runs may need fans with higher CFMs to compensate for reduced efficiency. Additionally, consider the fan's noise level, which is measured in sones. For a quieter experience, look for fans with a sone rating of 2.0 or lower.
Installing an Exhaust Fan
While installing an exhaust fan yourself can save money, it requires knowledge of electrical systems and compliance with local building codes. In almost every situation, hiring a professional for installation is preferable to DIY installation, as DIY installation often voids manufacturer warranties.
But, there are a few installation factors that you can consider before calling a professional.
- Placement: Fans should be located near sources of moisture or odors, such as showers or stoves.
- Electrical Requirements: Installation may require new wiring or connections to existing circuits.
- Ductwork: Venting outside is essential to avoid recirculating air back into your home.
Does Your Space Need an Exhaust Fan?
Ventilation fans are a worthwhile investment for any home, offering numerous benefits, including better air quality, reduced humidity, and improved comfort. But whether you need an exhaust or supply fan will depend mainly on the problem you must fix.
If your home shows signs of poor ventilation—condensation, lingering odors, or mold—it's time to consider installing or upgrading an exhaust fan. Also, exhaust fans can address and prevent unique issues like radon gas, cooking and commercial applications fumes, and ventilation in unusual spaces.
Choosing the right size fan, with the correct features and installation method, ensures adequate ventilation and long-term benefits for your home and health. Whether retrofitting an older space or building a new building, exhaust fans are essential to a healthy living environment.
Still trying to figure out the best exhaust fan for your space? Call our team of product experts at 1-800-934-9194 for product recommendations and support.
