Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
The short flexible or semi-rigid hose that connects the back of a clothes dryer to the wall is called a transition duct, and choosing one is a different job from cleaning the duct you already have. The material decides how much lint the duct holds, and a plastic or foil dryer vent hose is a documented fire risk. Length matters too: every dryer has a maximum transition duct length, and every elbow in the route reduces that maximum. Manufacturers publish different numbers for their own duct and their own dryers, so this page shows you how to find the right figures for your model rather than printing one number for every dryer.
This page covers buying and fitting a rigid or semi-rigid transition duct for a domestic dryer that vents through a nearby wall. It does not cover the full duct run through an attic or a long wall cavity, and it does not cover a gas dryer's own gas connection — a qualified person handles that part. If you only want to know whether a foil dryer duct is safe, or how long a dryer vent hose can be, the FAQ below answers both directly.
Safety
A PLASTIC DUCT OR A FOIL DUCT IS A FIRE HAZARD.
Lint collects in these materials and a fire can start.
Necessary equipment
| Item | Note |
|---|---|
| Tape measure | A tape measure gives the length of the duct route. |
| Screwdriver or nut driver | The screwdriver tightens the screw on a duct clamp. |
| Work gloves optional | The edge of a metal duct can be sharp. |
| Flashlight optional | A flashlight helps you read markings in a dark space. |
| Installation instructions for the dryer | The instructions give the maximum duct length and the elbow allowance. |
| Rigid or semi-rigid metal transition duct material | Do not select a plastic duct or a foil duct. |
| Two duct clamps material | The clamp closes around the duct without a screw inside it. |
| Metal duct elbow material | An elbow keeps the duct clear of a tight bend near the wall. |
Prepare the dryer
Estimated 2 min to 4 min
- Set the dryer to OFF.<1mReport a problem with step 1, Prepare the dryer
DISCONNECT THE ELECTRICAL SUPPLY TO THE DRYER BEFORE YOU MOVE IT.
Contact with the supply can give you an electric shock.
- Disconnect the dryer from the electrical supply.<1mReport a problem with step 2, Prepare the dryer
- Remove the plug from the wall outlet.
IF THE DRYER USES GAS, DO NOT MOVE IT YOURSELF.
A damaged gas connection can cause an explosion.
- Move the dryer away from the wall.2mReport a problem with step 3, Prepare the dryer
- Move the dryer only far enough to reach the connection.
- Do not pull the dryer by the door.
Measure the route
Estimated 3 min to 6 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Measure the route from the dryer outlet to the wall outlet.1mReport a problem with step 1, Measure the route
- The route follows the duct, not a straight line.
- Count the elbows that the route needs.<1mReport a problem with step 2, Measure the route
- An elbow reduces the maximum length that the dryer allows.
- Open the installation instructions for the dryer.<1mReport a problem with step 3, Measure the route
- Find the maximum duct length and the elbow allowance in the instructions.1mReport a problem with step 4, Measure the route
Select the duct material, diameter and length
Estimated 3 min to 7 min
Source: Overheated Clothes Dryers Can Cause Fires (CPSC Publication 5022) · tier 1 · accessed 2026-07-29
Source: How to Check Venting — Dryer · tier 1 · accessed 2026-07-29
SELECT A RIGID DUCT OR A SEMI-RIGID DUCT.
A plastic duct or a foil duct can trap lint and start a fire.
- Select a rigid duct or a semi-rigid duct.1mReport a problem with step 1, Select the duct material, diameter and length
- A rigid duct gives the best airflow.
- Use a semi-rigid duct only for a tight bend behind the dryer.
- Find the diameter on the label of the new duct.<1mReport a problem with step 2, Select the duct material, diameter and length
- A dryer duct is usually 4 inches across.
- Compare the route length with the maximum length in the instructions.<1mReport a problem with step 3, Select the duct material, diameter and length
- Subtract the length that the instructions give for each elbow.
- If the route is longer than the maximum length, select a shorter path.1mReport a problem with step 4, Select the duct material, diameter and length
- If a shorter path is not possible, ask a professional installer.
Remove the old duct
Estimated 3 min
- Release the clamp on the old duct at the dryer.<1mReport a problem with step 1, Remove the old duct
- Disconnect the old duct from the dryer outlet.<1mReport a problem with step 2, Remove the old duct
- Release the clamp on the old duct at the wall.<1mReport a problem with step 3, Remove the old duct
- Disconnect the old duct from the wall outlet.<1mReport a problem with step 4, Remove the old duct
- Examine the material of the old duct.<1mReport a problem with step 5, Remove the old duct
- Replace a plastic duct or a foil duct now.
Install the new duct
Estimated 6 min
- Connect the new duct to the outlet at the dryer.<1mReport a problem with step 1, Install the new duct
DO NOT USE A SCREW THAT ENTERS THE DUCT.
Lint catches on the screw and can start a fire.
- Install a clamp around the joint at the dryer outlet.<1mReport a problem with step 2, Install the new duct
- Tighten the screw on the clamp with a screwdriver.<1mReport a problem with step 3, Install the new duct
- The screw must not enter the inside of the duct.
DO NOT LET THE DUCT FORM A TIGHT BEND.
A tight bend reduces the airflow and makes each load take longer.
- Position the duct in a smooth curve.1mReport a problem with step 4, Install the new duct
- A tight bend can trap lint and reduce the airflow.
- Connect the other end of the duct to the wall outlet.<1mReport a problem with step 5, Install the new duct
- Install a clamp around the joint at the wall outlet.<1mReport a problem with step 6, Install the new duct
- Tighten the screw on the clamp with a screwdriver.<1mReport a problem with step 7, Install the new duct
- Make sure that no screen or grid sits inside the duct.<1mReport a problem with step 8, Install the new duct
- A screen inside the duct collects lint.
Feel the airflow before you finish
Estimated 5 min
- Connect the dryer to the electrical supply.<1mReport a problem with step 1, Feel the airflow before you finish
- Move the dryer back to its position.2mReport a problem with step 2, Feel the airflow before you finish
- Keep the duct straight as you move the dryer.
- Set the dryer to the air program.<1mReport a problem with step 3, Feel the airflow before you finish
- The air program uses no heat.
- Start the dryer.<1mReport a problem with step 4, Feel the airflow before you finish
- Feel the airflow at the exhaust hood outside.2mReport a problem with step 5, Feel the airflow before you finish
- Strong airflow shows a correct fit for the new duct.
- Weak airflow means a bend or a blockage in the route.
- Stop the dryer.<1mReport a problem with step 6, Feel the airflow before you finish
- Record the date and the duct material on paper.<1mReport a problem with step 7, Feel the airflow before you finish
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- transition duct
- Also called: dryer vent hose, dryer duct, vent hose, flexible dryer hose, dryer connector hose, transition hose
- semi-rigid duct
- Also called: flexible metal duct, accordion metal duct, corrugated metal duct, semi rigid dryer duct
- rigid duct
- Also called: solid metal duct, smooth-wall duct, hard duct
- duct clamp
- Also called: hose clamp, worm-gear clamp, vent clamp
- clothes dryer
- Also called: tumble dryer, dryer machine, drying machine, laundry dryer
When to use a professional
Stop if you cannot find the maximum duct length and the elbow allowance for your dryer. Ask the dryer manufacturer for this information.
Stop if the route is longer than the maximum length in the instructions. Ask a professional installer to find a different route.
If the dryer uses gas, do not disconnect the gas connection yourself. Ask a qualified service person to isolate the gas supply and move the dryer.
Ask a duct installer if the wall outlet or the outside vent needs a repair.
Common questions
What kind of dryer vent hose is safe to use?
The safest choice is a rigid metal duct; a semi-rigid metal duct is the usual choice for the short run right behind the dryer. The U.S. Consumer Product Safety Commission recommends rigid or corrugated semi-rigid metal duct over plastic or foil, because the flexible plastic and foil types trap lint more easily and kink more easily. GE Appliances states plainly that plastic duct work is no longer approved, and that its own foil duct is allowed only under strict conditions. This page follows the stricter, safer recommendation: pick rigid or semi-rigid metal, and treat foil as a last resort your dryer's own instructions must approve first.
Is a foil dryer duct safe?
Some manufacturers allow a UL-listed foil duct under strict conditions and short lengths, so owning one is not automatically a violation. The U.S. Consumer Product Safety Commission is more cautious: it recommends replacing a foil or plastic duct with rigid or corrugated semi-rigid metal duct, because foil traps lint and kinks more easily, and either fault can restrict airflow enough to build up heat. This page follows the CPSC's stricter choice — rigid or semi-rigid metal — rather than the narrower foil allowance. If foil duct is already fitted behind your dryer, that is a reasonable time to change it.
How long can a dryer vent hose be?
There is no single number, because the maximum transition duct length is set by the dryer manufacturer and it varies by model. As one example, GE Appliances limits its own UL-listed semi-rigid or foil transition duct to 8 feet (2.4 m) or less; your dryer's own installation instructions may give a different figure. Every elbow in the route also reduces the maximum length by an amount the instructions state. Read the installation instructions for your dryer before you buy a duct, rather than relying on a general rule.
What size dryer duct do I need?
Almost every domestic clothes dryer uses a 4 inch (100 mm) round duct; Whirlpool and GE Appliances both give this figure for their own dryers. A larger duct is not an upgrade: a wider duct slows the air, and lint is more likely to fall out of the airstream and build up inside. Check the diameter marked on the outlet at the back of your dryer before you buy a replacement duct.
Can I use screws to fit a dryer duct?
No. The U.S. Department of Energy's own weatherization guidance is direct: use a correct fastener, and do not let a screw penetrate into the duct. A screw that enters the inside of the duct gives lint something to catch on, and a build-up of caught lint is a fire risk. Fasten the duct with a clamp at each end instead.
Can I fit this myself if I have a gas dryer?
Fitting the transition duct itself is the same job on a gas dryer as on an electric one. What changes is moving the dryer to reach the connection: a gas dryer's own gas connection can be damaged if the dryer is dragged or pulled, and a damaged gas connection is a serious hazard. Ask a qualified service person to isolate the gas supply and move the dryer for you, then fit the duct once it is clear of the wall.
Related procedures
- How to clean a clogged dryer vent and lint duct
- How to test a dryer thermal fuse with a multimeter
- How to clean the lint filter in a tumble dryer
- Find and clean the moisture sensor bars inside a clothes dryer
- How to clean the drain filter on a front loading washing machine
- How to find and record the model and serial number of every appliance in the house
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 1Overheated Clothes Dryers Can Cause Fires (CPSC Publication 5022)
- Tier 1How to Check Venting — Dryer
- Tier 1Dryer - Installation Information for Exhaust Ducting
- Tier 1Vent a Clothes Dryer (Job Aid 17-1)
Revision history
Current version 1 · updated 2026-08-03 · next review due 2027-08-03
- v1 · 2026-08-03First draft. Material and diameter specifications reuse the existing domestic-clothes-dryer registry entries already verified for clear-dryer-vent (spec_key domestic-clothes-dryer|exhaust-duct-material|cpsc-dryer-fires-5022 and |exhaust-duct-diameter|whirlpool-dryer-venting); no new registry entry was written. Maximum length and the per-elbow length deduction publish as consult-the-installation-instructions: GE Appliances states 8 feet as its own limit for its semi-rigid and foil duct, but Whirlpool's own chart is per model, so no single figure is printed as if it applied to every dryer. Fastener guidance (a clamp, never a screw that enters the duct) comes from the U.S. Department of Energy Weatherization Assistance Program job aid 17-1, extracted directly from the PDF bytes because the file has no browser-readable text layer. Two new sources are proposed in data/sources-additions-choose-a-dryer-transition-duct.json and are not yet in data/sources.json; check 3 will not resolve them until scripts/sources_admit.py admits them. No competitor page was read or drafted from; the backlog entry names three already-registered sources and this record reuses two of them plus two newly read manufacturer/government pages.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.