Magnetic dryer vent and periscope: what the makers and the code say

Updated October 2, 2026 · Every figure checked twice against its source · How we verify

A magnetic dryer vent is a two-part coupling: one part mounts on the wall where the duct comes out, the other on the dryer's exhaust port, and magnets join them when the dryer is pushed back, so you no longer have to get between the dryer and the wall, its maker MagVent says. The 2021 International Residential Code does not name magnetic couplings or periscopes. Where it is adopted, the duct that connects the dryer to the exhaust duct must be a single length, listed and labeled to UL 2158A, no longer than 8 feet and not concealed within construction (M1502.4.3). On the MagVent pages we read, the UL 2158A claim names the hose its self-aligning models use, not the coupling, so check the label on what you install and ask your local code official.

Magnetic dryer vent connectors and dryer vent periscope pipes compared

Magnetic dryer vent connector: what MagVent says it does

MagVent's home page says its self-aligning magnets let you "do away with that extra length of dryer vent hose which usually gets crushed and restricted between the dryer and the wall."

• MV-180: for a vent path in a straight line. With perfect alignment it requires 4 inches of clearance behind the dryer. It handles offsets up to 3 inches center to center.
• MV-90: for a vent path that turns 90 degrees, down through the floor, up through the ceiling or off to the side. MagVent says it normally requires 5 1/2 inches of clearance and handles offsets up to 3 inches.
• MV-Flex: for awkward vent locations and offsets between 3 and 6 inches. You cut a minimum length of a transition duct of your choosing, and the magnets are joined by hand rather than self-aligning.

The self-aligning models still use a hose: MagVent's instructions say to attach the flexible duct to the dryer exhaust port with the supplied hose clamp. That hose is the part MagVent describes as "Zero Flame Spread, UL 2158A Approved Dryerflex Transition Hose."

What is a periscope dryer vent?

A telescoping duct, 2 by 6 inches in the Builder's Best and Almetal versions, for when the dryer outlet and the wall vent do not line up; Whirlpool's instructions list it "for use with dryer vent to wall vent mismatch". Builder's Best describes its 0 to 18 inch periscope as "a rigid aluminum clothes dryer duct designed for tight space installations", 2 by 6 inches, in two telescoping sections that are not reversible. Amana sells an 18 to 29 inch periscope that it says is designed for small laundry spaces with 2 1/2 inch clearance.

Whirlpool's electric dryer installation instructions show a periscope installation as one of two alternate installations for close clearances and list three kits by mismatch: part 4396037 for 0 to 18 inches, 4396011 for 18 to 29 inches and 4396014 for 29 to 50 inches, and tell you to refer to the manufacturer's instructions.

Magnetic dryer vent hose and the code

Chapter 15 of the 2021 International Residential Code says nothing about magnets or periscopes. Four of its rules matter for the connection behind the dryer:

• Follow the dryer maker. Clothes dryers shall be exhausted in accordance with the manufacturer's instructions (M1502.1).
• Transition duct. Transition ducts used to connect the dryer to the exhaust duct system shall be a single length that is listed and labeled in accordance with UL 2158A, not greater than 8 feet, and not concealed within construction (M1502.4.3).
• Joints. Exhaust duct joints shall be sealed in accordance with section M1601.4.1 and shall be mechanically fastened, and ducts shall not be joined with screws or similar fasteners that protrude more than 1/8 inch into the inside of the duct (M1502.4.2).
• Length. The exhaust duct may run 35 feet from the transition duct connection to the outlet, less an allowance for each fitting, and the transition duct is not counted (M1502.4.6.1). See how long a dryer vent can be.

The U.S. Fire Administration's dryer fire report adds that only flexible transition ducts listed by UL or another approved product safety testing agency should be used. Whether your inspector treats a coupling or a periscope as transition duct or as exhaust duct is a question for your local code official; the code text does not answer it. Our guide to dryer vent materials covers foil, flex, tape and screws in detail.

UL listing: what each maker's page claims

• MagVent: "MagVent's Self-Aligning Models Utilize Zero Flame Spread, UL 2158A Approved Dryerflex Transition Hose." The pages and instruction sheets we saved do not say the magnetic coupling itself is listed. The MV-Flex page carries no UL statement and has you supply a transition duct of your choosing, so the label to look for is on that duct.
• Builder's Best: its parts table for the 0 to 18 inch periscope has six rows, and only one, model 12276, carries the note "with baffle & UL® 2158A".
• GE Appliances: its parts store lists the PM08X10083 periscope as "UL listed" without naming a standard, and marks it no longer available.
• Amana and Almetal: the product and installation pages we read do not mention a UL listing.

Are magnetic dryer vents safe?

No code, agency or dryer maker source we read rates magnetic couplings either way. Whirlpool's installation instructions do say "Do not use an exhaust hood with a magnetic latch", but that line is about the hood outside the house; see our dryer vent cover guide. The same Whirlpool instructions say to use clamps to seal all joints, not to connect the vent with screws or other fasteners that extend into the duct and catch lint, and not to use duct tape. They do not mention magnetic couplings.

MagVent's own instructions carry warnings: a pinching hazard between the magnetic surfaces, a risk of harm to electronic devices and magnetic storage, and a pacemaker warning: "In close proximity, powerful magnets have been known to interfere with some types of pace makers with potentially fatal consequences." It says to consult a physician about handling the magnets.

Are periscope dryer vents safe?

No code, agency or dryer maker source we read tests or rates periscopes for safety. Whirlpool's instructions list periscope kits as an alternate installation for close clearances, without a safety finding. Builder's Best says periscopes provide nearly the same airflow as one semi-rigid metal flexible pipe with two Close Elbows®, and its 0 to 18 inch periscope page lists "Flame Spread:0" and "Smoke Developed: 0" under performance data, without naming a test standard.

On joints, Almetal's installation guide says never to use screws to fasten pieces together because screws or rivets project into the airway and catch lint, and to use metal foil tape to secure all duct pipe connections. M1502.4.2 says exhaust duct joints shall be sealed in accordance with section M1601.4.1 and shall be mechanically fastened, and that ducts shall not be joined with screws or similar fasteners that protrude more than 1/8 inch into the duct. The code text does not say whether Almetal's method meets that section; ask your code official. At the dryer, Almetal's guide has you secure the exhaust pipe extender to the dryer's exhaust vent with metal tape and the included 4-inch hose clamp, not tape the extender to the periscope, and says the extender normally slides 1 inch into the receiver.

How to install a magnetic dryer vent

MagVent's installation overview for the MV-180:

1. Check alignment. Make sure the dryer exhaust port and the wall exit point are within 1 to 2 inches of alignment (MagVent).
2. Mount the bracket and body to the wall. Unplug the dryer first, and check for live wires with an AC voltage sensor before driving screws into drywall (MagVent).
3. Mount the dryer-side union on the dryer exhaust port, fastening the flexible duct with the supplied hose clamp (MagVent).
4. Push the dryer into place and let the magnets complete the seal (MagVent).
5. Inspect the seal. MagVent says a quick visual check verifies it, using a mirror and flashlight in tight quarters (MagVent).

Periscope dryer vent installation

Almetal's procedure for its periscope kit, in short:

1. Measure. Measure the dryer's position against a reference point such as the washer (Almetal).
2. Disconnect. Unplug the dryer, or shut off the gas for a gas dryer, and remove the old hose and vent parts (Almetal).
3. Size the periscope. Pull it apart, cut it with tin snips, leave overlap when you reassemble, and file rough edges so they do not catch lint (Almetal).
4. Connect and seal. Attach the periscope to the outside vent, seal the duct connections with metal foil tape and fasten the periscope to the wall through the receiver hole (Almetal).
5. Fit the extender. Cut the exhaust pipe extender so it projects at least 1 to 1 1/2 inches beyond the back of the dryer, tape and clamp it to the dryer's exhaust vent, and slide the dryer back; the normal distance into the receiver is 1 inch (Almetal).

Before you buy: the check the product pages skip

1. Read your dryer's installation instructions. The code says dryers shall be exhausted in accordance with them (M1502.1). Whirlpool's, for example, say flexible metal vent must be fully extended and supported and should not exceed 7 3/4 feet in total (Whirlpool).
2. Find the listing label. The code wants the transition duct listed and labeled to UL 2158A (M1502.4.3); whether a coupling or periscope counts as transition duct is for your code official. Builder's Best's parts table puts a UL 2158A note on one of six rows for its 0 to 18 inch periscope.
3. Keep the connection visible. Transition ducts shall not be concealed within construction (M1502.4.3).
4. Ask the code official. Where the dryer maker's instructions set the duct length, the code has the code official given a copy of them at the concealment inspection (M1502.4.6.2). Ask how your coupling or periscope will be treated before the walls close.

If you would rather have the run, the transition duct and the connection done for you, see dryer vent installation and its costs, or the recessed dryer vent box, another way to keep the hose from being crushed. To get a price, use the form below and we will send your request to a company that serves your ZIP code.

Sources

1. International Code Council, 2021 International Residential Code, chapter 15, section M1502: codes.iccsafe.org
2. Whirlpool, "Electric dryer installation instructions" (W10267633A): whirlpool.com
3. U.S. Fire Administration, "Clothes Dryer Fires in Residential Buildings (2008 to 2010)", August 2012: usfa.fema.gov
4. MagVent, home page: magvent-dryervent.com
5. MagVent, "MV-180 - Straight Dryer Vent Path": magvent-dryervent.com
6. MagVent, "MV-90 - 90 Degree Dryer Vent Path": magvent-dryervent.com
7. MagVent, "MV-Flex - Any Way Dryer Vent Path": magvent-dryervent.com
8. MagVent, MV-180 installation instructions, front: magvent-dryervent.com
9. MagVent, MV-180 installation instructions, back: magvent-dryervent.com
10. Builder's Best, "Periscope 0-18-In": buildersbest.com
11. Amana, 18 to 29 inch "Dryer Telescoping Vent Periscope" (4396011RP): amana.com
12. Amana, "In-The-Wall Dryer Vent Periscope" (4392892): amana.com
13. GE Appliances parts, "Periscope Dryer Vent" (PM08X10083): geapplianceparts.com
14. Almetal Dryer Vent, "The Quick Connect® Periscope Kit": almetaldryervent.com
15. Almetal Dryer Vent, "How to Install a Dryer Vent": almetaldryervent.com

All sources read October 2, 2026.