As a clothes dryer tumbles and heats the laundry to dry it, the machine expels heat, moisture and lint from the vent. You should always vent your dryer outside, not indoors, to prevent damage to your home and keep your family as safe as possible. The risks of venting inside the house include fire, personal injury, loss of property, carbon monoxide poisoning and respiratory difficulties. Minimize the dangers from a dryer by never running it at night when you're sleeping or when you aren't home.
The chances of a fire increase when a dryer vent fills with lint, whether the vent is inside or outside. Dryer vents should be as short as possible to reduce the risk of lint building up. Ideally, the vent should follow a straight path from the back of the dryer to the outdoors, with no twists and turns. The U.S. Fire Administration reports based on data gathered from 2002 to 2004, that about 12,700 clothes dryer fires occur in homes each year, resulting in 15 deaths and 300 injuries. Damage costs reach about $99 million each year. The USFA recommends cleaning or having a professional inspect the vent for lint build-up a minimum of every two to three years. Keep a fire extinguisher nearby in case a fire does break out in or around your dryer.
Carbon Monoxide Poisoning
If you have a gas dryer and vent it indoors, you may subject yourself and your family to carbon monoxide exposure. Carbon monoxide is an odorless and colorless gas that poses serious health risks, and can be fatal. Install a carbon monoxide detector in the same room as your dryer as a precautionary measure.
Since dryers vented indoors send lint back into the air, they can trigger allergies and cause breathing difficulties, especially for people with asthma and other respiratory problems. Respiratory problems are likely to affect the elderly and infants more than healthy adults, making it even more important to properly vent the dryer.
Mold and Mildew
Mold grows where there is moisture, and a dryer vent sends plenty of moisture into the air. Your clothes dryer may be in the basement, an alcove on the main floor, in the bathroom or the kitchen, but regardless of location, mold spores get into the air and expose you and your family to a toxic environment. Dangers of mold include breathing problems, stuffiness and skin irritation.
The American Household Appliances Association recommends that you use UL-listed rigid aluminum or a steel duct instead of a spiral-wound aluminum hose or white vinyl hose to vent the dryer. Don't operate your dryer if there are any rips or tears in the vent hosing or in your lint trap.