LG dryers require 4-inch diameter rigid metal duct with a maximum length of 65 feet with 0 elbows. Deduct 6 feet per 90° elbow—maximum 4 elbows allowed. Flexible metal duct is limited to 8 feet total. Never use plastic, vinyl, or foil accordion duct.
Proper venting is critical for LG dryer performance and safety. Inadequate venting triggers FlowSense errors (d80, d90, d95) and creates fire hazards. This guide covers LG’s official specifications.
Maximum Duct Length Chart
LG specifies maximum vent lengths based on number of 90° elbows:
| 90° Elbows | Maximum Length |
|---|---|
| 0 | 65 ft (19.8 m) |
| 1 | 55 ft (16.8 m) |
| 2 | 47 ft (14.3 m) |
| 3 | 36 ft (11.0 m) |
| 4 | 28 ft (8.5 m) |
The rule: Deduct 6 feet from maximum length for each 90° elbow.
Maximum elbows: 4 (no more than 4 turns allowed)
Calculating Your Adjusted Length
- Measure total duct length from dryer to exterior
- Count all 90° elbows
- Add (elbows × 6 feet) to measured length
- Total must not exceed 65 feet
Example:
- Measured length: 25 feet
- Elbows: 3
- Adjusted length: 25 + (3 × 6) = 25 + 18 = 43 feet
- Maximum for 3 elbows: 36 feet
- This exceeds the limit—installation modification needed
Approved Duct Materials
Required: 4-Inch Rigid Metal Duct
The primary vent run should be 4-inch diameter rigid metal duct:
- Galvanized steel
- Aluminum
- Smooth interior surface for airflow
This is the only material approved for runs through walls, floors, and ceilings.
Allowed: Semi-Rigid Metal Duct (Limited)
Flexible metal duct (semi-rigid aluminum) is permitted only for the transition section behind the dryer:
- Maximum 8 feet total
- Use to connect dryer exhaust to rigid duct
- Must be smooth interior (not accordion-style)
- Keep as short and straight as possible
Even though 8 feet of flexible duct is allowed, shorter is always better. A 4-foot transition piece creates less airflow resistance than an 8-foot piece, reducing lint buildup and FlowSense alerts.
Prohibited Materials
Never use these materials—they’re fire hazards:
| Material | Why It’s Prohibited |
|---|---|
| Plastic duct | Melts, catches fire |
| Vinyl duct | Melts, catches fire |
| Foil accordion duct | Collects lint in ridges, crushes easily |
| Thin foil duct | Crushes, creates turbulence |
| Fabric duct | Burns, collects lint |
If your dryer currently uses any prohibited material, replace it immediately.
Prohibited Configurations
Beyond materials, certain configurations are not allowed:
-More than 4 elbows in the vent path -Screens or mesh over exterior vent (clogs with lint) -Venting into attic, crawlspace, or garage (must vent outdoors) -Shared vent with another dryer or appliance -Duct runs exceeding adjusted length limits -Kinked, crushed, or coiled ductwork
Exterior Vent Hood Requirements
The vent must terminate outdoors with a proper hood:
Required Features
- Gravity flappers or spring-loaded damper that opens when dryer runs
- Hood or cap to prevent rain/debris entry
- No screens or mesh (lint will clog them)
Hood Types
- Louvered hood: Multiple flappers open with airflow
- Single flap hood: One large flap, weighted or spring-loaded
- Dryer vent box: Recessed wall mount for close dryer placement
Maintenance
- Verify flappers open freely when dryer runs
- Clear any lint accumulation monthly
- Ensure hood isn’t blocked by landscaping, snow, or debris
Clearance Requirements
Maintain minimum clearances around the dryer:
| Location | Minimum Clearance |
|---|---|
| Sides | 2 inches |
| Above | 7.8 inches |
| Behind | 4-5 inches |
| Garage installation | 18 inches above floor |
The 18-inch garage requirement protects the igniter (gas dryers) from gasoline fumes that collect at floor level.
Fire Safety Statistics
Improper venting is the leading cause of dryer fires:
- ~15,000 dryer fires annually in the US
- 34% caused by lint buildup in vents
- 82% result from overheating due to restricted airflow
- Peak occurrence: January (winter usage), 1-2 PM
Warning Signs of Fire Hazard
- Clothes take multiple cycles to dry
- Dryer exterior extremely hot
- Burning smell during operation
- Exterior vent flap doesn’t open
- FlowSense codes (d80, d90, d95)
- Excessive lint around dryer connections
Maintenance Schedule
| Task | Frequency |
|---|---|
| Clean lint filter | After every load |
| Check exterior vent | Monthly |
| Professional vent cleaning | Annually (6-9 months for heavy use) |
| Inspect transition duct | Annually |
| Verify flappers work | Monthly |
When to Clean More Often
Clean vents every 6-9 months if you have:
- Large family (5+ loads/week)
- Pets (pet hair accelerates buildup)
- New construction nearby (drywall dust, debris)
- Long vent run (40+ feet)
- Multiple elbows
Installation Tips
Behind the Dryer
- Use semi-rigid metal duct, not foil
- Keep transition as short as possible
- Avoid sharp bends—use gentle curves
- Ensure dryer doesn’t crush duct against wall
Through Walls/Floors
- Use rigid metal duct only
- Seal all joints with foil tape (not cloth duct tape)
- Support horizontal runs every 4 feet
- Slope slightly downward toward exterior
At Exterior
- Use proper hood with flappers
- Position where you can check it
- Keep clear of landscaping
- Ensure it’s not visible from street (HOA compliance)
Heat Pump Dryer Note
LG heat pump dryers (DLHC series) are ventless—they don’t require exhaust ducting. These dryers:
- Condense moisture from air
- Drain water through a hose
- Require drain connection or manual emptying
Vent requirements in this guide apply only to vented dryers (DLE/DLEX/DLG/DLGX).
Model Coverage
Vent requirements apply to:
Electric vented dryers: DLE, DLEX series
Gas vented dryers: DLG, DLGX series
WashTower vented units: WKEX, WKGX series
Does NOT apply to: Heat pump dryers (DLHC, WKHC)—these are ventless
Sources
For official LG support: