What material is discouraged for use in electric dryer vents to ensure safety?

Plastic is discouraged for use in electric dryer vents primarily due to safety concerns related to its heat resistance and flammability. Unlike metal, which can withstand high temperatures and is less likely to catch fire, plastic can easily warp or melt under the heat generated by the dryer. Additionally, plastic can accumulate lint, which poses a significant fire hazard, especially if the lint blockages prevent proper airflow.

Metal ducts, on the other hand, are recommended as they are durable, resistant to heat, and less likely to trap lint compared to other materials. Flexible ducting can be acceptable if it meets specific standards, but it is typically recommended to use rigid metal ducting for dryer vents to minimize restrictions on airflow and to ensure a safer operation. Foam is generally not used in dryer vent applications due to similar concerns as plastic.

Overall, the choice of vent material is crucial for both the efficiency of the dryer and the safety of the home, making the use of plastic a less ideal option.