All About Garage Exhaust Fans

All About Garage Exhaust Fans – Ten Considerations Before You Buy and Install   

All About Garage Exhaust Fans - 10 things to consider before you purchase a garage exhaust fan.

When you think of exhaust fans, usually the room in the house that comes to mind first is the bathroom. We typically use these smaller exhaust fans to move steam from the shower and noxious fumes from the aftermath of chili night up and out of the room. Now while this is standard in most bathrooms, adding an exhaust fan to your garage is generally something that will need to be worked in as an addition. But functional and beneficial to your workspace – after you’ve installed one, you may wonder what life was like before.   

The concept of an exhaust fan is often no more than a broad base of a joke.  A good friend of mine had a custom-made electrical switch plate in his bathroom.  One toggle switch said ‘Light’, while the other simply said ‘FE’.  When people would question what FE meant, he would tell them it was the Eradicator device.  You can guess what the F stood for and just what odor it was eradicating.   

So, let’s get down to the basics here. We know that most homes, if not all, have an exhaust fan in the bathroom.  But why? For bathrooms, the primary reasons are humidity control, odor control, and removal of potentially toxic fumes and such.  That’s great for a bathroom, but how does that apply to a garage environment?  Well, let’s explore the new and exciting realm of the garage!   

Primary Purpose of a Garage Exhaust Fan  

The primary function of any fan is to move air around an area, most often an enclosed area, but not always. In the case of a garage, there can be many other concerns and/or motivations for installing an exhaust fan. Garages are unique in that they can (and should!) be used for more than simply parking a vehicle. They can be transformative in utility and purpose for many, many different uses. The trick at this point is to make sure the enclosure is maintained environmentally in a manner that assures enjoyment, efficiency, and safety. Determining the purpose, or better yet, multiple and future purposes of your garage can better prepare your plans for a proper build-out and/or modifications, thus leading you to the proper choice of an exhaust fan.   

Let’s take a moment to discuss the elements in the air that concern the homeowner the most.  If a garage is being purposed for woodworking projects, the elements that can affect the air environment range from simple aroma of wood to toxic chemicals to actual particulate matter in the air. Particulate matter is typically removed by specialized vacuums that can be attached to the woodworking tools themselves. (Saws and sanders have these kinds of attachment options). Toxic fumes, however, are another thing altogether.    

Fumes may be removed from the air through a filtration system, which is typically cost-prohibitive, especially in an environment that is not deemed a ‘clean room’. The next-best method is to circulate the air in a manner that removes and replaces the air within the room. This can be done but takes a little bit of planning to do it properly.   

In order to maximize the benefit from a Garage Exhaust Fan, it’s important to fully understand the concept and scope of your project. There are a number of factors to examine to determine what works best for you. These initially include the size of the room you want to vent, the airflow throughout the room, the actual cubic footage of the area of concern, and how to calculate that volume of air. Other considerations include local climate adaptations that may be needed, your electrical needs, and potential sound issues. Additionally, features like flaps on the fan enclosure, manual vs. automatic options on the fan operation, variable speed options, possible remote controllers should all be looked into before you purchase and install an exhaust fan. 

 1. Size of the Room Being Cleared by a Garage Exhaust Fan  

A critical element that is often misunderstood is the overall size of the enclosure you want to clear. The total cubic footage of the garage must be taken into consideration to choose an exhaust fan that will properly and efficiently remove any potentially toxic or offensive fumes/odors. Too small a fan will not effectively remove the air from the garage and gives a false sense of security and comfort. Just because a fan is in place doesn’t mean it is a good fit for the purpose intended.   

2. Airflow and/or Direction of a Garage Exhaust Fan  

It is important to determine the proper location for the exhaust fan installation location prior to the purchase. The determination of airflow needs to be done prior to the choice of the fan, due to proper inductive routing of the airflow.  It’s a little different from the air filter enclosures and air returns on the air conditioning in a home.  Locations are placed in order to ‘direct’ airflow to move it about the home and maximize the efficiency of an air conditioner.     

In the case of a garage, the desired result is not to simply move the air about, but rather to remove the air as completely as possible from the garage itself.  This necessitates both a vent – to allow fresh air to enter the garage from one end that is in a position that will draft over and through the areas where any toxins and dangerous fumes to pulled toward the exhaust fan and pushed safely outside.   

3. Cubic Feet of Air Per Minute Moved by a Garage Exhaust Fan  

To determine the appropriate fan size, it will be necessary to calculate the total amount of cubic air space that requires ventilation.  An easy calculation is to multiply the width times the height times the length of the garage area.  For example, a garage 20 feet wide by 20 feet deep by 8 feet high has a volume of 3200 cubic feet.    

 20’x20’x8’=3200 cubic feet    

Now, to determine how much volume needs to be moved to clear the air of fumes and odors is dependent upon how much air the garage fan can ‘push’ to the outside of the structure.  This is measured in CFM or cubic feet per minute.  Higher CFM can be accomplished by larger fan blades or greater revolutions per minute (rpm). Small fans like those found in bathrooms operate around 300 cfm, but a larger garage exhaust fan can generate over 4,000 cfm. Let’s assume our new exhaust fan operates at 1,000 cfm.  Given a garage area of 3,200 cubic feet and a fan that moves 1,000 cfm, the exhaust fan has the potential to move approximately 31% of the air in the room every minute the fan is in operation.    

While it’s dependent upon the location(s) of any vents, doors, or other areas of ambient air entering the garage, it is possible to clear/relocate a great deal of air.  Given our example above, we have the potential to clear the cubic volume of room air and fumes FIFTEEN times per hour!  

4. Local Climate Considerations for a Garage Exhaust Fan  

Ambient temperatures and moisture conditions can and will influence the location of your garage exhaust fan. Humid environments probably would be best to utilize a wall mount that pushes the air directly outside of the garage itself, but dry climates could be better suited for a ceiling mount that evacuates air into the attic, but eventually pushes the air out through another vent in the attic crawl space.  Believe it or not, in a desert environment like Arizona, where I live, it can actually help to cool the attic and possibly lower energy bills in the summer!  

Always consider what kind of air you are trying to evacuate to the outside environment.  Consistently noxious or toxic fumes should probably be vented directly to the outside through a wall mount. 

5. Electrical Needs for a Garage Exhaust Fan  

An electrical power supply will be necessary to run a garage exhaust fan.  Typically, all that is required is a standard 110-volt line. The greatest challenge will be routing the electrical conduit to the fan location itself.  If the garage is a new build with bare walls, this could be relatively simple to do. As in all cases, the DIYer should recognize and understand all necessary electrical codes and, if not comfortable with doing their own electrical work or if local codes do not allow it, be prepared to source a licensed electrical contractor to perform the work for them.  

6. Sound Level of a Garage Exhaust Fan  

It should always be assumed that any electrical device will generate some kind of noise. The degree of that noise level is often directly related to the cost of the fan, but not always. Perform your due diligence and research the specifications for noise levels in decibel rating.  A good rule of thumb is the larger the fan, the greater the noise level.  

7. Flaps to Eliminate Pests in a Garage Exhaust Fan  

An exhaust fan in a garage is designed to remove offensive odors, as well as toxic fumes, but also, to move air for temperature control.  The more air displaced requires larger garage fans and a larger fan enclosure means a bigger hole in the wall, so to speak. While larger openings are great for allowing air to move out, it also can allow any variety of pests to move in, thus requiring flaps on the garage fan system. Ideally, flaps will close automatically, thus making it difficult for pests like insects, rodents, vermin, and such. All those little guests that you really don’t need in your fortress of solitude. Flaps also can assist in preventing ambient air of an uncomfortable temperature from re-entering the garage environment.    

8. Manual Settings vs. Automatic in a Garage Exhaust Fan  

Are you interested in having your garage exhaust fan operate independently or perhaps you may only want it operable when you are actually in the environment itself?  A typical work environment is generally set up on a manual system, but if this is an area that is used for entertaining, such as a garage sports gathering, you may want to consider something that is thermostatically controlled. The thermostat option may require additional equipment in the form of wiring and a thermostat.  

9. Variable Speed Option on a Garage Exhaust Fan  

The variable speed of a garage exhaust fan may also be an option of interest. Remember that the movement of air can also have a cooling effect and the speed of the fan can affect the degree of cooling.  While it’s not the same as air conditioning, it can still add an element of comfort. There is also the noise aspect. The faster the speed, typically greater the noise level, but if you’re using equipment that is generating fumes or particulate matter, then faster is better.  

10. Remote Control for a Garage Exhaust Fan  

A remote control is primarily for convenience. Me, I’m on the side of having one, but I’m lazy.  Well, that’s not altogether true.  It’s often more practical to be able to use a remote when working with equipment or relaxing in a lounge chair with a cold drink next to you.  Okay, you got me.  I am lazy.   

 The cost is usually a little greater on fans with a built-in remote, but generally worth it.  Here’s an example of a unit that has the option as part of the purchase package: 

It’s important to note there are add-on options for those who already have a garage exhaust fan that did not come with it.  Here’s an example of such a unit… 

 Again, a remote control is an option, not a necessity.  Unless you’re me, that is. You know… lazy. 

Benefits of Adding a Garage Exhaust Fan   

The benefits of a garage exhaust fans are many.  Any kind of practical addition on a home typically adds to the value of a home.  Safety, however, is always my go-to.  Use your garage only for parking the car?  Exhaust fumes and potential carbon monoxide poisoning from an idling car can be dangerous.  Use your garage for woodworking?  Fumes from varnishes, stains, epoxies, and particulate matter are always a consideration regarding safety.  Are you a welder?  Some materials being welded, such as galvanized steel, require aggressive ventilation.  It only makes sense to do everything possible to improve an environment for both safety and comfort reasons.  A garage exhaust fan is one of the easiest means to improve that environment.  

Closing Thoughts 

As we can see here, a garage exhaust fan, while technically an option, but is in my opinion a necessity.  I like to do a multitude of things in my garage.  That multitude of events, operations, activities, entertaining, etc. requires good airflow.  If I’m tuning a vehicle up and the engine is running, I want excellent ventilation.  If I fire up the flat-screen with several of my friends while watching the game, I don’t want to be sweating like crazy.  This is Arizona and we have waaayyy too many months of high temperatures here.  The last thing I need is hot and stagnant air where I’m hanging out.  I decide to actually attempt to get creative with any kind of woodworking power tools, paint, stain, etc.?  I need to know I’m not going to get sick from fumes. 

 The bottom line is that it’s your call to determine the comfort or safety level you would prefer, but don’t just sell yourself short thinking there are no options available. Do your research, and reap the many benefits of having a garage exhaust fan in your garage!  

If you are looking for more ways to cool your hot garage, check out this article, 10 Ways to Cool Your Hot Garage.