Dryer taking two cycles? A restricted exhaust duct is the usual cause.

Air Duct Cleaning Dulles, Virginia
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Dryer vents & home exhaust · Dulles, VA 20166

Dryer Vent and Home Exhaust Cleaning

Your dryer, kitchen hood and bathroom fans each push air out of the house through their own ducts, separate from the heating and cooling system. When those ducts clog or come apart, the result ranges from damp walls to a house fire. This guide covers all three.

Quick answer

Clean the dryer lint screen every load and the dryer exhaust duct regularly — failure to clean is the leading factor in home dryer fires. Make sure kitchen and bathroom exhaust vents outdoors, never into the attic. Call a professional for long, hidden or roof-terminated runs.

  • 31%of home dryer fires: failure to clean
  • 35 ftVirginia code limit for dryer exhaust ducts
  • $135–$360Dryer vent cleaning, Northern Virginia
Round louvered exhaust vent cap with one bent louver, mounted on a white stucco exterior wall between two windows
A bent louver like this one can keep a vent flap from closing. Stock photo by Leo Tang on Unsplash.

Three Exhaust Systems, Three Different Risks

Home exhaust systems compared
SystemMain riskWarning signs
Clothes dryerFire from lint buildup; wasted energyLong drying times, hot laundry room, flap barely opens, burning smell
Kitchen range hoodGrease buildup; smoke and moisture left indoorsWeak suction, grease drips, fan noise, lingering cooking smells
Bathroom exhaust fanMoisture and moldMirror stays fogged, peeling paint, musty smell, dusty grille

Dryer Vents: The Fire-Safety Job

The U.S. Fire Administration reports that failure to clean was the leading factor contributing to home clothes dryer fires from 2018 to 2020, at 31 percent. The Consumer Product Safety Commission's advice is simple: clean the lint screen before or after every load, never run the dryer without it, and clean the vent and exhaust duct periodically so the outdoor flap opens freely.

The lint screen can't catch everything. Lint that slips past settles in elbows and long horizontal runs, which is why townhome laundry rooms on upper floors need attention most often. The dryer vent cleaning page walks through a full professional cleaning.

What Virginia's Residential Code Requires

Key exhaust rules in the 2021 Virginia Residential Code
RuleApplies to
Discharge to the outdoorsDryer, kitchen hood (listed ductless hoods excepted), bathroom
Keep the duct independent of other exhaust systemsDryer, kitchen hood
Never discharge into an attic, crawl space or inside the buildingKitchen and bathroom exhaust
Smooth-interior metal duct, 4-inch diameterDryer
35-foot maximum length, reduced for each elbowDryer, unless the manufacturer allows longer
Backdraft damper at the outside cap; no screensDryer
No booster fans in the ductDryer
Smooth, airtight duct with a backdraft damperKitchen hood

Source: 2021 Virginia Residential Code, Sections M1502, M1503 and M1505 (via UpCodes). Local amendments and your appliance's installation manual also apply.

Why Screens Don't Belong on Dryer Vents

It's tempting to screen a dryer vent to keep birds out. The code forbids it, because lint catches on the mesh and blocks the exhaust. A working backdraft damper keeps most animals out while letting lint pass. If birds have already moved in, the nest and the lint behind it need to come out before the dryer runs again — see bird nest and lint removal.

Townhomes and HOA Communities

Townhomes make up a large share of housing around Dulles, and many put the dryer on an upper floor with the exhaust running to the roof or a high side wall. Those runs are longer, harder to reach and often subject to HOA rules about roof access and exterior caps. The townhome and HOA vent guide covers what to ask before booking.

Dryer Vent and Exhaust Services

Each page covers the risks, the code rules that apply and typical costs.

Dryer Vent Repair

Crushed, disconnected or overlong runs rebuilt to code.

Dryer vent repair

Dryer Vent and Home Exhaust FAQs

Do dryer vents really need to be cleaned?

Yes. The U.S. Fire Administration reports that failure to clean was the leading factor in home clothes dryer fires from 2018 to 2020, at 31 percent. The lint screen catches most lint, but some always passes into the exhaust duct. Long runs, many elbows and roof terminations collect it fastest.

How do I know if my dryer vent needs to be cleaned?

Clothes take longer than one cycle to dry, the dryer or laundry room gets hot, the outside vent flap barely opens while the dryer runs, or you smell something burning. Lint around the outside cap is another sign. Any of these means the exhaust duct is restricting airflow.

What is the typical cost for dryer vent cleaning?

In Northern Virginia, dryer vent cleaning typically runs about $135 to $360. Short runs to an exterior wall sit at the low end. Long townhome runs, roof terminations and vents that need repair or bird nest removal cost more.

How do you clean a dryer exhaust vent?

Unplug the dryer, and shut off the gas if it's a gas unit. Pull it away from the wall, disconnect the transition duct and clean it and the wall opening. Run a vent brush through the duct toward the outside, then clear lint from the exterior cap and make sure its flap swings freely. Long, roof-terminated or hidden runs are best left to a professional.

Start With the Dryer Vent

It's the exhaust duct with the highest fire risk, and the quickest to fix.

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