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Clothes Dryer Venting Checklist

One of the most often neglected homeowner duties a home inspection will reveal is that of maintenance of the clothes dryer venting system. It’s very common, beginning behind the dryer, to find evidence of restriction and lint buildup indicating this as an area the homeowner has been ignoring. Continuing to the crawlspace, sometimes attic, and/or exterior will reveal further violations of the system in general, not limited to debris buildup, disconnects resulting in high humidity in enclosed areas, and missing or improper materials.

Generally speaking, lint and debris buildup over time within your venting system will cause your dryer to vent at less than optimum efficiency, increasing energy costs and wear and tear on your dryer appliance. This undesirable situation also sets the stage for potentially hazardous conditions including exhaust fires and conducive conditions for mold. Carbon monoxide poisioning may also be present with gas powered dryers.

In a recent advertisement/training video, Farmer’s Insurance indicated there are 15,000 dryer fires per year from flammable lint balls! Obviously, their message is regular cleaning and inspection of your dryer venting system as a necessary homeowner duty in preventing disaster.

Make a promise to yourself to routinely review your dryer venting system, from dryer to exterior. Here are some helpful tips to ensure you’re operating at peak efficiency and maximum safety:

  • Duct material should be metal, not vinyl. Metal flex ducting should be used sparingly as it tends to trap lint and moisture. Smooth wall galvanized or aluminum is preferred.
  • No penetrations, like screws, should exist at the interior of the vent ducting.
  • Duct length from dryer to exterior vent should never be greater than 25 feet; less distance if turns or right angles are involved. Every 90 degree turn will shorten your allowable distance by 5 feet.
  • Duct vents should exit to the exterior with secure and covered vent cap.
  • Exterior vents should have working flappers that open when the dryer is venting and closed otherwise. This will keep out cold air and pests.
  • There should be no visible lint buildup at any connection from dryer to exterior.
  • Duct vents at exterior should be a minimum of 3 feet from any other opening; window, door, other vents, etc.
  • Duct vents at exterior should be at least 6 feet from the A/C condensing unit.
  • Duct vents should never be terminated in the attic or crawlspace.
  • Never combine dryer venting with any other venting source.
  • Lastly, check your appliance filter before each load to be dried.

The Chimney Safety Institute of America (CSIA) recommends CSIA Certified Dryer Exhaust Technicians perform dryer vent inspections annually to ensure safe and efficient operation of your clothes dryer system.