Booster Fans originally came out on the market NOT for the application of dryer exhausts, but AC Ducts. The idea was, if the AC Trunk was X amount of feet long or more, it would perhaps be good practice to install a booster fan to help “boost” the airflow moving through the AC Trunk. Similarly, this same logic was used in reference to dryer exhaust ducts.
After professionals in the HVAC/ Dryer Vent realm started using the product for the application of dryer exhaust duct &/or booster fan manufacturers promoting the use of this for dryer exhausts, the manufacturers eventually started promoting & recommending “booster fan maintenance”, since, lint is blowing through the fan, where-as in contrast when installed in originally intended destination, HVAC ducts, no debris or material is blowing through the fan.
From my second hand experience, 99% of people who have booster fans do NOT stay on top of the annual preventative maintenance that booster fans manufacturers recommend. The “maintenance” is defined as simply cleaning out the booster fan and removing any lint in there, which, can only be done so by removing it all together from the vent system and then re-installing it, which is a project in and of itself and can be more complicated & time-consuming when 1) installed in such a way where it makes it impossible or nearly impossible to do this or 2) access in general is challenging.
When code did allow for booster fans, it also necessarily required an “access panel” to the booster fan for maintenance, troubleshooting or future removal. We’ve been in a number of situations where, access was never made and we had to located the booster fan using our camera technology and then create access for the homeowner.
Booster Fans were recently once allowed by building code & in some cases even required to be used for the application of dryer exhausts. However the code changed around 2022 & Booster Fans are no longer allowed (with one exception that will be noted momentarily). In saying that, dryer manufacturers have never recommended them (see below provided pictures, one from G.E & one from Whirpool).
We’ve also never recommend them, largely because dryer manufacturers don’t and we follow and encourage people to follow their recommendations (similarly to how you would an automobile manufacturer recommendations about things). But in addition to that since so many of our customers have problems with them, the become a “money-pit” trying to fix/ troubleshoot or replacing – or even just the required maintenance that needs to be done.
There is ONE exception that code allows, it’s called a Dryer Exhaust Duct Power Ventilator (DEDPV). But it’s important to first note that again, dryer manufacturers specifically state they do NOT recommend hooking up the dryer to a dryer exhaust that has a Booster Fan or DEDPV.
The DEDPV is similar to a booster fan, however, it has an additional component that code requires which is a light panel that is supposed to be mounted on the wall where the dryer is. It’s a red and green light which indicates if the booster fan is working/ working properly. So in addition to the fan needing to be installed, wiring and this light panel also need to installed.

The BEST solution for folks that need to assist their airflow is none of these products, the best solution in our opinion, is what dryer manufacturers already offer, which is dryers specifically made for “Long Vents”. They are sometimes referred to as, “long vent dryers”.
These are a great solution because you don’t have to deal with the headache(s) of fix/ troubleshooting/ maintaining your booster fan or DEDPV. These special dryers, shockingly do not cost any extra from what I’ve found in comparison to a normal dryer. A few years back I populated a list of these dryers from the manufacturers website. However I refer to the list as a “living document” because new models come and older models may be phased out. What I found was, most dryer manufacturers make these special “long vent dryers” and that some of them have all the bells and whistles and “smart technology” like some people like, whereas some models I found are just “standard” models without all the bells and whistles. Obviously the more features on the dryer the higher the cost.
Finding these machines you can either 1) Call the manufacturer directly and inquire or 2) search on each dryer manufacturers site for the term “Long Vent” & “Long Vent Dryer”. I’m happy to share my current list also of course, but I can’t guarantee it’s up to date. You could always do a general search on the internet for “long vent dryer” as well.
These dryers essentially have a booster fan inside of them. What I mean is, the fan in the dryer blows at 2 or 3 times the speed of a normal dryer!
In reference to the code change, any time code changes, people are grand-fathered-in. However, from my understand when you renovate or remodel something in some way shape or form at that point it’s supposed to be brought up to code. So, in saying that, if a booster fan fails and no longer works, if the person is trying to be code compliant, they have 2 options. Option #1 is not replacing the booster fan at all & just removing it. Option #2 is replacing it with something that is code compliant, which is currently the DEDPV, despite it not being recommended.
We not only troubleshoot booster fans but we also remove them. Anytime we remove a booster fan it leaves a 4-6 inch gap in the duct which means we have to add duct to make the exhaust system ‘whole’ again. After we do this and complete the cleaning, we then conduct an airflow test using a meter called an anemometer that reads airflow. We can immediately determine if the dryer that is on site can handle that vent length and advise from there. In every case we have done this, we have found that, even without a special dryer the dryer CAN handle the vent length, however, depending on the frequency of usage the resident may need to be strict about adhering to a 12 month schedule.



Now to transition to two final points. One on how to clean the duct with a booster fan and the final topic of discussion being the hazards associated with a booster fan.
There are many companies out there that do NOT now how to effectively clean a dryer vent with a booster fan. If you know you have a booster fan, make sure whomever you hire knows how to handle that; and ask questions like, “Tell or explain to me your process on how you clean the dryer vent with a booster fan installed”. You may or may not know that my Technicians and I are “Certified Dryer Exhaust Technicians”. I am also a “Junior Instructor” with the Chimney Safety Institute of America (CSIA) who offers that education, training and certification on Dryer Vents (an chimneys). In addition to this, I recently wrote two chapters for the upcoming update edition of our C-DET Service Manual, one chapter was about everything a technician needs to know about booster fans/ DEDPVs. So, in saying that, we know how to get the job done properly.
Lastly the problems/ hazards that can come about due to booster fans and what to look for.
We’ve found that booster fans or DEDPV’s make noises for one of two reasons. Reason #1, it’s a sign/ symptom that the fan needs maintenance, due to an accumulation of lint in the fan housing compartment. The more lint in the fan housing, the more noisey it will be, eventually if packed with lint it will stop working. Reason #2, the fan was installed in such a way where, when the fan is running It’s vibrating against other building material.
It’s very important to know when a booster fan no longer work. In saying that, it’s important to know how they are supposed to work. The booster fan/ DEDPV is supposed to automatically trip on within a minute of the dryer being turned on, as a result of the booster fan detecting airflow, due to a small airflow tube that leads from the dryer exhaust to a fitting on the booster fan that’s connected to a switch. When the booster fan gets that airflow it turns on. They are supposed to turn off within 3-5 minutes generally of the dryer being turned off.
You can generally, subtly hear them, when the fan is on (hear them behind the wall or in the ceiling). However, another way to identify if the booster fan is operating is, after running the dryer for 1-5 minutes assuring that the fan is supposed to be on at this point, turn the dryer on and take the lint trap screen out. Afterwards, you may not only hear the fan or hear a reasonable draft of air, but you can put your hand or fingers a little ways into the lint trap and you’ll feel air movement.
The reason why it’s important to know how it works is so that when you know when it stops working. When it stops working it will soon after act as an immediate blockage, even before that point, it’s already negatively impacting the airflow/ performance of the dryer. Anything that causes a blockage in a dryer vent is considered a hazard, because a blocked dryer vent causes a variety of hazards. I explain those in this very short video.
I’ll highlight 3 of them. Reason #1 When the booster fan is blocked all that hot humid air that can’t properly discharge, has to go somewhere. A blockage creates a back-pressure of air, meaning, a percentage of that hot humid air (along with the lint) is now returning to your dryer. This is why your dryer times increase and this is also why the dryer cabinet and lint trap will accumulate lint at a more rapid rate that normal. This also necessarily means your dryer is overheating which can cause heat related stress on the parts and effective the lifespan of the parts and the overall machine & it’s very common that parts related to the heating of the machine will fail, resulting in both appliance repair and the need for a vent cleaning.
Reason #2 is water accumulation in the fan and the dryer exhaust duct. There have been numerous occasions where people who had a fan, kept running and running the machine knowing or not knowing the fan was non-operational. As a consequence, that humid air that couldn’t properly discharge, started condensating in the duct and fan itself. Depending on the size load of laundry there’s still a half gallon to a gallon and a half of water in the clothes/ towels you’re attempting to dry (which is the purpose of the dryer). We’ve found and evacuated 1-2 gallons of water from peoples dryer ducts &/ or booster fans before. We’ve also seen on a number of occasions that due to neglecting situations like this, that water started “raining” through people’s ceiling, due to it leaking from the duct. That’s not good, especially when in a Condo.
Reason #3 – the worst hazard of course is a dryer fire. This would be as a direct result of a lack of maintenance and persistence in using the dryer when there’s clearly a problem. Normal dryer times are 20-40 minutes. It should serve as a homeowner “red flag” if the dryer is taking more than once cycle consistently. If the dryer is taking 3-4 cycles, consider that a hazard and you’ve waited way to late to get the service done and need it done ASAP. All that lint that can’t get out will build up in your dryer at a more rapid rate than normal. It doesn’t take a rocket scientist or firefighter to discern, the more flammable lint in your machine, the higher the risk of a dryer fire. Dryer fires are the 6th leading cause of house fires, it’s called a dryer fire because they exclusively start in the dryer, not the vent, which is why it’s SO IMPORTANT to hire a company offering the complete service (cleaning both the dryer by way of taking it apart & the vent). Most companies do NOT offer the complete service, leaving the homeowner potentially still at risk.
If you have any question, comments or concerns or need some consulting don’t hesitate to reach out! Thank you for supporting the Space Coast’s most qualified & well-reviewed dryer vent cleaning company – we are 10 reviews away from hitting 1,000 5-Star reviews!


