Dryer Venting 101

Lint happens. Yes, even if you clean the lint screen filter every time. Lint still gets through and builds up over time within the dryer and exhaust vent of your home.

  • Clothes taking too long to dry
  • "I have to run them 2-3 times!"
  • Door has moisture and wet, matted lint stuck to it
  • Dryer wont start (thermal fuse may be blown)

These are the MOST COMMON issues which often point to a dryer venting issue. Many customers resort to buying expensive heating elements, fuses, or even replace the dryer altogether. I've seen customers do it...and then they call a tech to find out nothing was wrong with the dryer after all. It was the dryer exhaust vent (part of the house) that was the issue.

Drying Clothes

Clothes Dryers cycle the heating element on and off. There is a blower wheel inside the dryer that pulls the heated air through the drum tumbling your clothes, through the clothes, pulling out lint and moisture, forcefully blowing it out of the dryer through the exhaust vent, and eventually outside.

If the dryer cannot get the moisture and lint OUT of the dryer...where does it all go? Nowhere! It stays inside the dryer or gets trapped inside the exhaust vent. Because of this, the heater reaches maximum temperature more quickly and the thermostat shuts off the heater prematurely. This reduces the heat inside the dryer, reducing or eliminating the dryer's ability to expel the heat and moisture inside the dryer. This may also lead to failure of thermal fuses, excessive stress on the motor, and a list of other failures.

The need to vent

The shorter the vent, the better. The dryer will work more efficiently, the clothes will dry more quickly, and your dryer should last longer. A dryer vent should span less than 30 feet. If there's a 90 degree elbow in the span, that counts as 5 feet. But, the main point is...the shorter, the better. Below is an example of a improperly installed or poorly maintained dryer vent.

"Droops" or sagging in the dryer venting will eventually lead to a buildup of moisture and lint, which will cause it to sag even more or even break away from the venting supports. I have cut open dryer venting underneath a house and found a half gallon of water inside the vent. You'll see images at the end of this article that show this. This is due to an excessive buildup of moisture and lint that was unable to properly be exhausted because of a clog or restriction within the vent or at the vent cap on the exterior of your home.

Common Vent cap types

Many common backups/restrictions occur because of the cap on the outside of the home.  Lets take a look at the most common vent cap types.

Louvered Vent Cap

Elevated Vent Cap and Pest Cover

Roof Vent Cap

Elevated Vents or Roof Vent Caps are often hard to get to...and even harder to clean. Most have a screen to prevent birds from getting inside. This screen essentially becomes a lint filter and will eventually become thicker than a blanket. No heat or lint will be able to escape. You may need an appliance service technician to check your vent cap for restrictions, clean or replace the screen, and perform a vent cleaning service to ensure all buildup has been removed.

Many ground-level vent caps are flat, louvered caps or are a standard 90 degree vent hood. Some have a removable rodent/bird screen or removable louvers to allow access for dryer vent cleaning. Vent caps or hoods with a pest or rodent screen should be checked often for buildup. As long as the proper venting material has been installed, you can clean the vent yourself with a Dryer Vent Cleaning System.


Clean Sweep

If your vent is rigid or semi-rigid, you can use a vent cleaning system attached to a power drill to thoroughly clean your dryer vent. You can literally brush off the worry of a costly appliance repair or vent fire. The Gardus LintEater 10-Piece Rotary Dryer Vent Cleaning System is one of the most affordable, at-home solutions to maintaining the cleanliness of your dryer vent. Prevent vent fires and prolong the life of your dryer.


Vent Duct material options

Rigid Metal

Semi-Rigid Metal

Aluminum Foil Duct

Rigid Metal - THE BEST

It's not that expensive, but can be difficult when working around obstacles. EASY to clean with a dryer vent brush or the vent cleaning system above. Duct seams should be taped together with a high grade aluminum tape. Do not use duct tape. Duct Tape will not hold up to the moisture and heat. Some technicians choose to use sheet metal screws. The tips of the screws on the inside allow a snag point for the lint to attach to and could potentially snowball into a clog or restriction.

Semi-Rigid Metal - GOOD

This is a good choice. It can be cleaned like rigid metal venting. One downfall is if it becomes crushed, it does not bounce back. A customer recently had her brand-new dryer installed and the installers used (often required) Semi-Rigid Metal behind her dryer. After they pushed it back against the wall, it crushed the vent like a soda can.

A few days later, the thermal fuse blew and her dryer had to be repaired. A similar incident occurred to a separate customer when the detergent fell behind the dryer. The vent had been crushed and become restricted. Again, the thermal fuse inside the dryer blew to prevent a vent fire because of excessive heat buildup.

Aluminum Foil Duct - FAIR

This is mainly used inside the home to connect the dryer exhaust to the dryer vent, typically behind the dryer. The accordion-like structure easily collapses in length like a slinky when the dryer is pushed back against the wall.

Flexible Plastic or PVC - AVOID

Plastic and PVC should be avoided. Older homes may have used flexible plastic which can become brittle and tear easily over time. PVC pipe is often used in slab foundations. You will find it may clog frequently, rapidly, and may even "gurgle" when being cleaned because of trapped moisture in the pipe.

lint and vent photos

Dryer Vent Not Heating?
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