Dryer Vent Cleaning in Missouri

How the inspection works

We start by tracing the vent route from the back of the dryer to where it ends outside — usually an exterior wall or the roof — and checking how both ends can be reached. USFA notes that building codes require dryers to exhaust directly outdoors; if a vent ends in an attic, crawlspace, or other enclosed space, we'll point it out, and correcting it is a job for a qualified installer.

We look at the transition duct behind the dryer. CPSC notes that most manufacturers specify rigid or corrugated semi-rigid metal duct, and that plastic or foil accordion-type duct can more easily trap lint and is more likely to kink or crush.

We check whether exhaust air is escaping outside and whether the outdoor vent flap opens while the dryer runs — a check CPSC and NFPA also recommend homeowners make.

• Vent route, approximate length, and number of turns
• Transition duct material and any kinks, crushing, or disconnections
• Exterior hood condition, flap movement, and any screen that could trap lint
• Signs of nesting or other blockage at the outside opening

Sources: U.S. Fire Administration — Clothes Dryer Fires in Residential Buildings (2008–2010), Topical Fire Report Series Vol. 13, Issue 7; U.S. CPSC — Overheated Clothes Dryers Can Cause Fires (Publication 5022); NFPA — Clothes Dryer Safety tip sheet

Access: exterior walls, roofs, attics, crawlspaces, and multi-unit buildings

Most dryer vents are cleaned from both ends: from the laundry area with the dryer pulled away from the wall, and from the outside vent hood. There needs to be room to move the dryer without straining its gas line, power cord, or any water connection.

Exterior wall terminations need a clear path to the outside vent hood. Ground-level hoods are usually straightforward; higher hoods need safe ladder placement.

Roof terminations are evaluated case by case. Roof pitch, height, material, and weather affect whether a roof vent can be reached safely. If it can't, we'll explain what was cleaned from inside and what wasn't.

Vent ducts that pass through attics or crawlspaces may need a safe access point so connections along the run can be checked.

In condos, apartments, and other multi-unit buildings, vents may run long distances, connect to building-owned exhaust systems, or end on a roof or upper-story wall the building controls. Check with your HOA or property manager first — shared or building-owned vents may need their approval or their own contractor.

Basement laundry rooms and moisture

About 53% of Missouri homes have a basement (RECS 2020), and where the laundry is down there, the dryer's exhaust starts below grade. MU Extension links damp basements to humid air condensing on cool surfaces and recommends venting dryers outside to remove moist air; its weatherizing guide also lists dryer vent wall connections among the places to check for air leaks.

A basement vent that has to climb and turn is worth watching: USFA explains that when a vent is long or has many bends, moisture in the warm exhaust condenses on the vent walls and attracts lint. During a cleaning visit we check that the transition duct is connected at both ends and that exhaust leaves through the outside hood. Sealing or rebuilding a leaking wall connection isn't part of cleaning; it's quoted separately only if offered, or a qualified installer can handle it.

Sources: U.S. EIA — 2020 Residential Energy Consumption Survey, state highlights: structural characteristics; University of Missouri Extension — How to Prevent and Remove Mildew: Home Methods (GH5928); University of Missouri Extension — Insulating and Weatherizing Your Home (GH4881); U.S. Fire Administration — Clothes Dryer Fires in Residential Buildings (2008–2010), Topical Fire Report Series Vol. 13, Issue 7

North versus south: snow at the hood

NOAA notes that northern Missouri averages more than 20 inches of snow a year, compared with less than 5 inches in the south. NFPA's dryer tip sheet includes a winter check worth knowing in the north: make sure the outdoor vent flap is not covered by snow.

Sources: NOAA NCEI State Climate Summaries 2022 — Missouri; NFPA — Clothes Dryer Safety tip sheet

What cleaning can't do

Cleaning removes accumulated lint and debris from the parts of the vent system that are cleaned. It addresses a known risk factor, but it cannot guarantee that a dryer fire will never happen: in USFA's data, failure to clean was the leading factor contributing to ignition, not the only one.

Crushed, kinked, or plastic or foil transition ducts may need to be replaced by a qualified installer. CPSC recommends replacing plastic or foil accordion-type ducting with rigid or corrugated semi-rigid metal duct. Cleaning also doesn't correct a vent that is damaged, poorly routed, or ends indoors.

Gas lines, electrical connections, and the dryer itself are outside our scope. NFPA advises having gas dryers inspected by a qualified professional to make sure the gas line and connection are intact and free of leaks.

Vent cleaning doesn't replace everyday habits: NFPA and CPSC advise cleaning the lint filter before or after every load, and NFPA advises turning the dryer off if you leave home or go to bed.

• Damaged, disconnected, or improperly routed vents need a qualified installer
• Dryer repair or interior cabinet cleaning needs a qualified appliance service person
• Gas line or connection concerns need a qualified gas professional
• Outlet, plug, or wiring problems need a qualified electrician

Sources: U.S. Fire Administration — Clothes Dryer Fires in Residential Buildings (2008–2010), Topical Fire Report Series Vol. 13, Issue 7; U.S. CPSC — Overheated Clothes Dryers Can Cause Fires (Publication 5022); NFPA — Clothes Dryer Safety tip sheet

Signs you may want an inspection

USFA notes that if heavy items like jeans or towels take a long time to dry, or clothes feel hotter than usual at the end of the cycle, a clogged dryer vent is likely the problem. CPSC adds that clothes still damp after a typical cycle may mean the lint screen or exhaust duct is blocked.

If you smell burning, stop using the dryer, turn it off, and have it checked by a qualified professional before using it again. If there is smoke or fire, get everyone out and call 911.

• Drying takes longer than it used to, or clothes are still damp after a normal cycle
• Clothes feel hotter than usual at the end of a cycle, or the outside of the dryer gets noticeably hotter than it used to
• Lint collecting around the outside vent hood, or a vent flap that doesn't open when the dryer runs
• Nesting material or debris at the outside vent opening
• Plastic or foil accordion-style duct behind the dryer, or duct that is crushed or kinked
• It has been about a year since the vent was cleaned — NFPA suggests cleaning lint out of the vent pipe once a year, or more often if drying takes longer than normal

Sources: U.S. Fire Administration — Clothes Dryer Fires in Residential Buildings (2008–2010), Topical Fire Report Series Vol. 13, Issue 7; U.S. CPSC — Overheated Clothes Dryers Can Cause Fires (Publication 5022); NFPA — Clothes Dryer Safety tip sheet