Which vent termination features help prevent backdraft and water intrusion?

Which vent termination features help prevent backdraft and water intrusion?

• A. A metal vent cap with a screen.
• B. A backdraft damper and weatherproof hood.
• C. A decorative cap and vent cover.
• D. A plastic plug on the exterior.

Answer: (B)

The main idea is to stop exhaust from coming back into the building and to keep rain and other moisture out of the vent. A backdraft damper acts like a one-way valve: it opens to let dryer exhaust escape, but closes to prevent outside air from flowing back in when the dryer isn’t actively venting or when wind pushes against the vent. A weatherproof hood provides shielding over the termination, typically with a sloped or sheltered design that sheds rain and blocks wind-driven water from entering the duct while still allowing air to exit. Together, they address both problems—preventing backdraft and reducing water intrusion. Other options may offer screens or cosmetic tops that don’t reliably stop backflow or water entry, and a plug would completely block venting.

The main idea is to stop exhaust from coming back into the building and to keep rain and other moisture out of the vent. A backdraft damper acts like a one-way valve: it opens to let dryer exhaust escape, but closes to prevent outside air from flowing back in when the dryer isn’t actively venting or when wind pushes against the vent. A weatherproof hood provides shielding over the termination, typically with a sloped or sheltered design that sheds rain and blocks wind-driven water from entering the duct while still allowing air to exit. Together, they address both problems—preventing backdraft and reducing water intrusion. Other options may offer screens or cosmetic tops that don’t reliably stop backflow or water entry, and a plug would completely block venting.