The CFM (cubic feet per minute) of a residential clothes dryer exhaust can vary depending on various factors, such as:
- the type and model of the dryer
- the length of the vent
- the number of bends in the vent
- Lint build-up in the vent
However, on average, most residential clothes dryers have an exhaust CFM of around 150-200.
But, the ideal rate is the maximum CFM you can achieve given your situation. Because the higher the CFM the faster your clothes will dry.
Clothes Dryer Exhaust CFM Varies By Model
Brand-new high-end dryers can blow up to 300 CFM of air. Conversely, a dryer that is low quality and decades old may only blow 100 CFM of air.
So, suppose your dryer is standard quality or better and less than 20 years old. In that case, the dryer itself is unlikely the reason why it’s not blowing enough air.
However, if you have an ancient, low-quality dryer, it might be time for an upgrade.
Shorter the Dryer Vents Have Higher CFMs
If your laundry room is on the first floor of a two-story home and your dryer vent exhausts through your roof, your dryer vent should be shorter.
The longer your dryer vent, the harder it has to work to blow air through it. So, If your dryer vent is longer than 15′, you should reroute it to make it shorter.
A short dryer vent length allows the dryer to blow higher CFMs. Consequently, its critical that your dryer have the correct vent specifications.
The Less Bends In The Vent, The Better
If your dryer has no bends in the vent with a horizontal duct venting it outside, it could be up to 20′ long without the CFMs being too low.
But, most dryers have three or more bends in the vent. And each turn reduces the overall optimal efficiency length by 5′.
So, if you have three bends, the vent shouldn’t exceed 5′ feet for optimal dryer CFM levels. If your dryer has four 90-degree turns in the vent it cannot operate at peak efficiency.
Lint Build-Up Reduces CFM
The vast majority of the time, when a dryer’s CFM is too low, it’s because lint build-up is in the dryer vent.
When lint builds up in the vent, it reduces the diameter of the duct. Which, in turn, reduces the CFM of the dryer.
Unfortunately, when the CFM decreases, the heat increases because the dryer cannot blow all the heat out of the vent.
Consequently, this increases the risk of highly flammable lint catching on fire. Over 13,000 house fires a year in the United States start from an overheated dryer igniting lint in the vent.
Regularly cleaning and maintaining your dryer vent ensures that the dryer is functioning at its optimal CFM and minimizes the risk of any potential hazards. If you are looking for dryer vent cleaning in Phoenix and Scottsdale, AZ, call us. We can clean your vent for you!
CFM & Clothes Dryer Efficiency
It’s important to note that the CFM of your clothes dryer exhaust is directly related to efficiency.
For example, a higher CFM means the dryer is expelling more moist air. Therefore, your clothes dry faster.
Which, in turn, lowers your utility bill. Also, when your dryer runs less, it has less wear and tear – increasing the lifespan of your dryer.
Final Words
Overall, understanding the CFM of a residential clothes dryer exhaust is essential for efficiency and safety. If you need clarification on the CFM of your dryer, check the manufacturer’s specifications. Or contact a dryer vent cleaning company to assess and service your vent.
