Dryer vent safety is not something at the top of most people’s list of important factors when buying a home. In a recent report released by the National Fire Protection Association (NFPA), fires caused by dryers or washing machines between 2010 and 2014 were responsible for approximately 16,000 house fires, 450 injuries, 13 deaths and $240 million in property damage per year. The vast majority of these fires, 92%, involved clothes dryers. The number one cause of a fire related to a dryer is due to dust, lint or fiber. This shows just how important dryer venting and maintenance are for keeping your home safe. Home and occupant safety is something every professional home inspector takes seriously.
Here is a general summary on proper dryer vent guidelines.
Dryer Vent Installation
Clothes dryers should always be installed in accordance with the manufacturer’s instructions. Dryer exhaust systems should be independent of any and all other house systems and convey the moisture and any products of combustion (lint, dust, pet hair, etc) to the outside of the building.
Dryer Vent Duct Length, Material, and Size
In general, the maximum length of a clothes dryer should not exceed 25 feet from the dryer location to the wall or roof termination. This 25 foot distance is reduced for each and every turn the duct makes, 2.5 ft for a 45* turn and 5 ft for a 90* turn. It also should be noted that this 25 foot distance does not include the transition from the dryer to the dryer duct. The duct material should be smooth walled rigid metal, and should not be connected with sheet-metal screws or any fasteners that would extend into the duct, which would both restrict airflow and catch lint. Duct size is typically 4 inches, but should meet the manufacturer’s installation instructions. PVC piping should only be used if the dryer vent goes into the slab.
Dryer Vent Duct Termination
Exhaust ducts should terminate outside the building, but not within 3 ft of any openings into the building. The exhaust duct termination needs to be equipped with a back draft damper and should not have screens or coverings that would trap lint, dust, etc.
In every home inspection report, we will always recommend cleaning your dryer vents annually for both fire safety reasons and energy efficiency. Below are some of the dryer vents we’ve seen in the past week while performing home inspections in Tallahassee and Crawfordville.
Rain cover and backdraft damper are both missing, allowing pests and moisture to enter the vent. Also vent is full of lint, and needs to be cleaned.
Rooftop dryer vent with metal grate that traps lint, pet hair, etc.
Lint, dog hair, etc that came from the dryer vent. This build up over time can lead to a house fire.
Dryer exhaust vent has a screen installed, this should be removed. Screens trap lint, debris and even feathers! This will reduce dryer efficiency and could lead to a build up that could start a house fire.
Dryer vent is improperly terminated in garage, not to the exterior. This will cause a build up of humidity, dust, lint, pet hair etc in the garage.
