The 11 Warning Signs Your Brooklyn Dryer Vent Is Clogged

We are Vent Pro NYC, a Brooklyn-based dryer vent cleaning crew. Most of the calls that come into our line start with some version of "I think something is wrong with my dryer." The customer is usually right. By the time most Brooklyn homeowners pick up the phone, the vent has been telling them it is clogged for weeks or months. The signs were there. They just looked like a tired appliance.

This is the post we want every Brooklyn homeowner, co-op shareholder, condo owner, renter, and building super to read before they call us. It is the eleven warning signs we have learned to recognize over thousands of jobs in Park Slope brownstones, Brooklyn Heights co-ops, Williamsburg condos, Bay Ridge row houses, and everything in between. Each sign is a piece of physical evidence with a specific physics explanation. Two of them should make you stop using the dryer until somebody inspects it. We will flag those.

A clogged dryer vent is not a binary condition. The early signs show up when airflow drops about 25 to 35 percent below normal. The serious signs show up when airflow drops 50 percent or more. By the time you have a burning smell or the dryer's high-limit thermostat is tripping, the vent has been telling you something is wrong for at least three to six months. Trust the early signs. The boring ones, the "my dryer just feels off" ones, are the most important.

The 11 signs (introduction)

Here is the full list. We will go through each one in depth, but if you want the quick scan first, this is what to look for.

1. Loads take noticeably longer to dry — what used to be one cycle is now two.
2. Clothes come out of the dryer hot but still damp.
3. The dryer body itself is hot to the touch after a normal cycle.
4. A burning smell during the cycle, especially a hot-dust or scorched-fabric note.
5. The lint screen is barely dirty after a full load (yes, this is bad).
6. The laundry room feels humid or musty after a cycle.
7. The exterior vent hood flap does not open, or only opens partway.
8. Mice, birds, wasps, or other pests are showing up in the laundry room.
9. The high-limit thermostat trips and the dryer shuts off mid-cycle.
10. It has been two or more years since the vent was last cleaned.
11. The dryer hums louder, vibrates harder, or sounds different than it used to.

If you are seeing three or more, the vent is clogged. If you are seeing the burning smell or the dryer body is painfully hot, stop reading and unplug the dryer now. Then come back and finish the article.

Companion reads: our complete Brooklyn dryer vent cleaning guide and the piece on Brooklyn dryer vent fires. The second one is uncomfortable reading but it is the reason we wrote this list.

Sign 1: Loads take noticeably longer to dry

This is the single most common complaint we hear and it is also the most reliable early indicator. A healthy modern electric or gas dryer with a clean lint screen and a clean vent will dry a normal medium load — roughly seven to eight pounds of mixed cotton — in 40 to 55 minutes on a normal heat setting. A full load of heavy cotton (towels, jeans, sweatshirts) should finish in 55 to 75 minutes. Bedding takes longer, but rarely more than 90 minutes.

What "noticeably longer" means in practice is what we want to be specific about. If you have always known your dryer to finish a normal load in about 45 minutes and now the same load needs 75 minutes, that is a 60 percent increase in cycle time. That is not a worn-out heating element or a tired motor. That is a vent that has lost a significant fraction of its airflow.

The physics is simple. A dryer is a heater plus a fan. The fan moves moisture-laden air out of the drum, through the lint screen, through the duct, and out the cap. If the duct is clogged, the fan still spins at the same rpm but moves a fraction of the air it should. The heating element is still throwing the same watts of heat into the drum. The drum gets very hot, the clothes get very hot, but the moisture has nowhere to go. It evaporates, condenses back onto cooler clothes, then evaporates again. The cycle takes much longer because moisture is being recycled instead of removed.

The threshold we use: if a load that used to dry in one cycle now needs two, the vent is restricted by at least 40 percent. That is well past the point where we would recommend a professional clean, and where electric bills start to climb. We have customers in Park Slope who came to us because their utility bill jumped 30 dollars a month and their thermostat readings did not explain it. The dryer did.

Diagnostic threshold: if a normal load now takes 50 percent longer than it did a year ago, schedule a vent inspection. Do not wait for the next sign.

One caveat: if you recently moved, replaced your dryer, or had work done on the duct, your baseline has changed. The "noticeably longer" comparison only works against your own historical cycle times on the same machine. New Brooklyn brownstone owners should treat the age-of-last-cleaning question as their primary signal.

Sign 2: Clothes come out hot but still damp

This is the diagnostic version of sign 1, and the one homeowners notice first because they pull a load out of what they thought was a normal cycle and find clothes that are uncomfortably warm but not actually dry. Heat is being delivered. Moisture is not being removed.

If you have ever opened a dryer and felt a wave of steam roll out, that is a healthy dryer at the end of a properly timed cycle. The moisture is being carried out of the drum in the airstream as the fan vents it. When the vent is clogged, the steam has nowhere to go. It re-wets the clothes. You open the door and instead of steam, you get a hot, wet sock that feels like it just came out of the washer.

This is also the symptom that causes the most appliance service calls that turn out to be vent problems. The homeowner assumes the heating element is failing, the repair tech arrives, runs a diagnostic, finds the element is fine, and either charges a fee for nothing or sells a part the customer did not need. We talk to a lot of customers who paid $200-$400 for a heating element replacement only to have the same symptom come back two weeks later. The element was fine. The vent was clogged.

If you have a new heating element and your clothes still come out damp, the next call is to a vent cleaner.

Sign 3: The dryer body is hot to the touch

A healthy dryer running on a normal heat cycle will warm to the touch on the front panel and the top, somewhere in the range of 95 to 105 degrees Fahrenheit. Warm, not hot. You can rest your hand on the top of the dryer without flinching.

A clogged-vent dryer runs much hotter because the heat that should be going out the duct is staying inside the cabinet. The surface temperatures we measure with a laser thermometer on a vent-restricted dryer are typically 120 to 145 degrees. At 130 and above the surface is uncomfortable for more than a second or two. The cabinet feels almost like a small heater is running inside it. Effectively, one is.

The temperature matters for three reasons. The internal components (motor bearings, drum rollers, belt, control board) operate well above their design temperature range, and they fail prematurely — we have seen dryers with clogged vents need new motors at five years instead of the fifteen to twenty the manufacturer specifies. The heating element works harder than it should, raising the electric bill and shortening the element's life. And a dryer cabinet that runs at 140 degrees for hours at a time is sitting next to drywall, baseboard, and laundry-room cabinetry. Over years, the wood substrates dry, shrink, and crack. They become better fuel if a spark ever does occur.

Quick informal test: at the end of a cycle, place your palm flat on the top of the dryer. Count to ten. If you can leave your hand there comfortably, the surface is probably under 115 degrees. If you pull it away before five seconds, you are over 130 and the vent is restricted.

Sign 4: A burning smell during the cycle

This is one of the two signs that should make you stop using the dryer immediately. We want to be specific because not every smell is dangerous. The smell of "warm laundry" is not what we are talking about.

The dangerous smells fall into three categories.

A hot-dust smell, like a baseboard heater the first time it runs in October. This is dust on the heating element being burned off. On a properly venting dryer the dust should be carried out the duct, not lit up on the element repeatedly. A persistent dust smell usually means airflow is so low that lint and dust are accumulating inside the heat exchanger and re-burning every cycle.

A scorched-fabric smell, like an iron left too long on a cotton shirt. This is fabric inside the drum reaching temperatures where the fibers break down. It means moisture removal is so impaired that the clothes themselves are getting hot enough to scorch. Stop the cycle.

The third smell is the one to be most alert to: a thick, slightly chemical, acrid smell that does not match anything you associate with normal laundry. That is compacted lint, packed somewhere in the duct or against the heat exchanger, starting to char. Lint that has been wet, dried, and heated again can ignite at temperatures as low as 350 to 400 degrees Fahrenheit, which a clogged-vent duct can reach during a long cycle. Once it ignites it can smolder for hours before flame is visible. Smoldering lint is the precursor to almost every dryer fire we have seen reports on.

Stop-using-it rule: if you smell anything burning during a cycle, stop the cycle, unplug the dryer (for gas, also shut off the gas valve), and do not run it again until the vent is inspected. This is the difference between a vent cleaning and a fire department call.

More on the conditions that turn a clogged vent into a fire in our piece on Brooklyn dryer vent fires.

Sign 5: The lint screen is barely dirty (this is bad)

This is the counterintuitive one. Most homeowners assume a full lint screen after every load means a healthy system, and a near-empty screen means the dryer is "clean." That is exactly backwards.

A healthy dryer with a healthy vent deposits a substantial visible mat of lint on the screen on every full load — a layer covering most of the screen, maybe an eighth of an inch thick. Towels produce a lot. Synthetic activewear produces less. Cotton sheets produce a lot. Every load should produce some.

If you have been pulling out a near-clean screen after every load for months, the lint is going somewhere else. The most common explanation is that airflow at the screen is so low that the lint is not being pushed into the pleats. Instead it is settling further upstream: on the lint-screen housing, in the bypass passages, on the heat exchanger fins, and in the first few feet of the duct.

The other explanation, less common but worth knowing, is that the screen seal has failed and lint is bypassing the screen entirely. This happens when the screen is bent, when the housing gasket has degraded, or when the screen was installed wrong after a cleaning. Either way, lint is accumulating inside the airflow path and inside the duct.

If your screen has always been dirty after every load and is suddenly clean, do not interpret that as the dryer "running cleaner." Interpret it as the lint going somewhere worse.

Sign 6: The laundry room feels humid or musty

A dryer evaporates water out of clothes and sends the moisture-laden air outside. A typical full load contains roughly two to three pounds of water by weight. If the vent is clear, all of that water exits as warm humid air through the cap. If the vent is clogged, the water has to go somewhere else.

In a restricted system, moisture leaks out at every seal: at the back of the dryer where the transition hose connects, at the lint screen housing, sometimes through the drum door seal, and in extreme cases through the dryer's cabinet vents. Over a few weeks of cycles this raises the humidity in the laundry room substantially.

Signs to watch for: the laundry room feels noticeably more humid than the rest of the apartment after a cycle. Walls or ceiling above the dryer show fresh paint blistering. Baseboard or floor near the dryer feels slightly damp. A musty smell that did not used to be there, especially in a closet or windowless laundry room. In a brownstone, the laundry room feels warmer and more humid than the basement even though the dryer is the only heat source.

If your laundry room is growing visible mildew on the walls or behind appliances, that is the most extreme version of this symptom and a strong signal the vent has been restricted for a long time. We have pulled dryers out of Brooklyn brownstone closets where the wall behind the dryer was black with mildew and the transition hose was waterlogged. The vent was almost completely blocked in every case.

Sign 7: The exterior hood flap does not open

If you can get to your exterior vent cap, this is the easiest sign to verify. A healthy dryer running a normal cycle pushes the louvered damper or backdraft flap on the cap fully open. Stand outside, watch the cap during a cycle, and you should see it open. You should feel warm humid air a foot below the cap. The flap should be steadily held open, not shuddering.

On clogged systems we see three patterns.

The flap opens partway, maybe a quarter or third of full travel, and shudders. The dryer is producing some airflow but not enough to fully overcome the flap's weight and the friction of debris in the louvers. The vent is restricted, not completely blocked.

The flap does not open at all. The dryer is running but the cap is sealed shut. Either the duct is completely blocked, or the cap itself is sealed by lint compacted into the hinge, paint from a previous facade job, ice (in winter), or a pest nest. We see this most often on parapet-mounted brownstone caps that have not been inspected in five or more years.

The flap is gone entirely. It has rusted off, been knocked off by a bird, or been stolen from a ground-floor cap. The duct is open to the elements and pests, and you have a different problem (see sign 8).

If you have access to your cap, watching the flap during a cycle is the single most informative thirty seconds you can spend on diagnosing your vent. If the cap is on a four-story brownstone roof you cannot do this yourself, which is why we measure it on every job. More in the long-vent-run guide for Brooklyn brownstones.

Sign 8: Mice, birds, or insects in the laundry room

This is one of the most reliable indicators of a structural problem with the exterior of your vent system, and one that homeowners misdiagnose as a pest problem when it is really a vent problem.

A dryer vent terminates outside. The cap is supposed to keep pests out while letting exhaust out. When the cap is missing, damaged, or has a stuck-open damper, pests follow the air path inside. They enter the cap, walk down the duct, and exit at the back of your dryer.

The most common Brooklyn version is a starling or house sparrow building a nest inside a parapet-mounted vent cap. Starlings can build a substantial nest inside a 4-inch vent in two to three weeks. We have pulled five-pound nests of twigs, leaves, and feathers out of brownstone roof caps in Crown Heights and Bed-Stuy. Once the nest is in, airflow drops dramatically and pests have a clear path into the building. More in bird nests in Brooklyn dryer vents.

The second version is a mouse trail. Mice can squeeze through a quarter-inch gap, so a damaged cap or missing flap is an open invitation. They walk the warm duct toward the heat source and emerge into the laundry room. We have had customers in Park Slope, Cobble Hill, and Bay Ridge call about a mouse problem in the laundry room only, and in every case the vent cap was the entry point.

The third version is wasps and other insects. Carpenter bees especially like to bore into the foam or wood backer plate that holds the cap to the facade.

If you are seeing pests specifically in the laundry room and nowhere else, do not call an exterminator first. Call a vent cleaner. The exterminator can kill what is already inside but cannot close the door pests are coming through.

Sign 9: The high-limit thermostat trips repeatedly

This is the sign that means your dryer's safety mechanism has started doing its job. Good news because the alternative is the dryer continuing to overheat. Bad news because you are running out of time.

Every modern dryer has a high-limit thermostat (sometimes called a thermal cutoff) that monitors temperature near the heating element or blower housing. When it exceeds a safe threshold — typically 180 to 200 degrees Fahrenheit on the cabinet side — it cuts power to the heating element. The drum may keep turning but the heat stops. On some models the thermostat is one-way and has to be replaced after it trips; on others it is a self-resetting bimetallic switch that cools off but trips again on the next cycle.

What you see: the dryer is running, the drum is turning, but after twenty or thirty minutes there is no heat. Clothes are still wet. Restart the cycle and the same thing happens.

This is not the heating element failing. This is the element being shut off by the safety circuit because the dryer is overheating. The overheating is almost always a clogged vent.

We treat this as urgent. Do not run more cycles until the vent is cleaned. If you replace the high-limit without cleaning the vent (which an appliance repair tech will sometimes do if they do not ask about vent maintenance), the new thermostat will trip on the same cycle. You will have spent money bypassing a safety device that was correctly identifying a real problem.

The pattern: a building super calls us about a dryer that "needs a new thermal fuse." We arrive, measure airflow at 90 FPM (severely restricted), clean the vent, and the thermostat does not trip again. Sometimes the original thermostat is fine. Sometimes it has been tripped enough times that it does need replacement, but the cause was always the vent.

Sign 10: It has been two or more years since the last cleaning

This is a calendar sign, not a symptom, on the list specifically because the absence of obvious symptoms does not mean the vent is clean. We have seen Brooklyn brownstone vents that ran four years with no homeowner complaint, and we pulled six pounds of compacted lint out of them.

The reason: human ability to notice gradual changes is limited. If your cycle time increases by 30 seconds every month for three years, you will not notice it. But three years later your cycles are 18 minutes longer than they used to be. The homeowner just never had a "wait, this is taking too long" moment.

The right cadence for Brooklyn dryers depends on building type and household size. Full breakdown in the post on how often to clean your Brooklyn dryer vent. Short version:

Configuration	Cleaning interval
Apartment, short run, 1 to 2 people	Every 18 to 24 months
Apartment, short run, 3 to 4 people	Every 12 to 18 months
Brownstone, long roof run, any household size	Every 12 months
Pre-war co-op or condo, shared shaft	Every 12 months
Single-family home, medium run	Every 18 months
Any household with pets that shed	Every 9 to 12 months

If your last cleaning was more than 24 months ago, the vent is clogged enough to warrant cleaning even without the other symptoms. The cost of preventive cleaning is the same as reactive cleaning. The cost of waiting is much higher, in both money and risk.

Sign 11: The dryer hums louder or vibrates more than usual

This is the subtlest sign and the one homeowners most often dismiss, but it has a specific physical cause.

A dryer's blower fan is sized for a specific airflow against a certain static pressure. A clean vent presents little static pressure to the fan. A clogged vent presents a lot. As back pressure on the fan increases, the motor works harder to maintain rotation speed, draws more current, runs hotter, and the entire chassis vibrates more — the fan is essentially trying to push air through a closed door.

What you hear: the dryer sounds different. It hums at a slightly lower pitch. It rattles more in its housing. Small items on top of the dryer (a basket of clothespins, a bottle of detergent) walk across the surface during a cycle. The neighbor in the apartment below complains about a vibration they did not hear before.

This is one of the harder signs to assign to "the vent" with confidence because dryers also vibrate more as drum rollers wear, belts loosen, and leveling feet rust. The way we differentiate: vent-caused vibration is constant and consistent across all cycles. Roller-caused vibration is intermittent and louder at certain points in the rotation. Belt-caused vibration is a low rumble that gets worse over months.

If the vibration is constant, and especially if paired with any of signs 1 through 4, the vent is the cause. Cleaning resolves it. Not cleaning will eventually burn out the blower motor, which is a much more expensive repair.

What to do if you see ANY of these

We get to this section a lot of different ways. Sometimes the homeowner has noticed one sign and called us proactively. Sometimes they have ignored eight signs for two years and the dryer is now a fire risk. Whichever you are, here is the protocol.

DO:

• Stop using the dryer until somebody has inspected the vent. If you are seeing any of signs 3, 4, or 9 (hot cabinet, burning smell, high-limit trips), this is not optional. Unplug the dryer. For gas dryers, shut off the gas valve behind the dryer.
• Pull the dryer out and look at the transition hose. The transition hose is the flexible four-inch hose that connects the back of the dryer to the wall fitting. If it is foil or plastic accordion, it is probably bunched, kinked, or crushed against the wall. If it has visible lint inside it, that is a symptom of restricted airflow further upstream, not the cause.
• Vacuum behind the dryer. This will not clean your vent, but it will remove the loose dust and lint that has built up on the floor and the back of the cabinet, and it will reduce the local fire load.
• Take a photo of the exterior vent cap if you can see it. If the cap is on a parapet four stories up, you cannot. If it is on the side of a Bay Ridge row house six feet off the ground, photograph it from below with your phone's zoom. We can often diagnose the cap problem from a photo before we arrive.
• Call a professional. This is what we do. The number is (718) 541-5567 and you can book online.

DO NOT:

• Run another cycle "just to see." If you have a burning smell or a hot cabinet, running another cycle is how vent fires start. We have seen this in incident reports more times than we care to recount.
• Attempt to clean a long roof run yourself. The brushes you can buy at Home Depot are rated for 25-foot runs maximum. A Brooklyn brownstone roof run is 40 to 60 feet with multiple elbows. Using a residential brush kit on a roof run is how you wedge the brush head off the cable inside your duct, which is a much more expensive problem to solve than the original clog.
• Replace the heating element or the high-limit thermostat without cleaning the vent first. This is the single most common waste of money we see homeowners make. If a vent is clogged, the new heating element will fail just like the old one did. Clean the vent first. Then, if the symptoms persist, replace the element.
• Ignore the signs because the dryer "still works." A clogged-vent dryer can run for years before something catastrophic happens. The fire risk is real but it is also probabilistic. You may go ten years without a fire on a 90 percent blocked vent. You may also go three months. The way to not find out which one you are is to not run it that way.

A 60-second self-diagnostic test

Before you call us, here is the test we recommend every homeowner run. It takes about a minute and it will tell you with high confidence whether the vent is the problem.

Step 1. Start with an empty dryer. Take a damp washcloth, wring it out until it is just barely damp, and toss it in the drum.

Step 2. Set the dryer to a normal heat cycle, 30 minutes. Start the cycle.

Step 3. Five minutes in, place your palm flat on the top of the dryer, near the back. Count to ten. If you can hold it there for the full count without flinching, the cabinet temperature is reasonable.

Step 4. Eight minutes in, if you can safely access the exterior vent cap (a ground-floor cap on a row house, for example), go outside and hold your hand a foot below the cap. You should feel a steady flow of warm humid air. The damper or louvers should be open.

Step 5. Open the door at the 30-minute mark and pull out the washcloth. It should be bone dry, or close to it. A healthy dryer will dry a single damp washcloth in 5 to 8 minutes. If it is still damp at 30 minutes, the vent is severely restricted.

Step 6. Check the lint screen. There should be a thin layer of fluff on it from the washcloth, plus any residual lint from the previous load. If the screen is completely clean, lint is bypassing it somewhere in the system.

That is it. If you fail steps 3, 4, 5, or 6, the vent needs to be cleaned. If you pass all of them, the dryer is venting at acceptable performance and you can probably wait until your normal maintenance interval. The test is not perfect — it does not catch slowly accumulating lint upstream of the blower — but it catches roughly 85 percent of the cases we are called for.

The professional diagnostic

When we arrive we run a more rigorous version of the same diagnostic, with instruments. This is what separates a real inspection from a guy with a leaf blower.

Airflow velocity at the dryer collar. We put an anemometer at the dryer's exhaust collar with the dryer running on a normal heat cycle. A healthy dryer measures 1,200 to 1,500 feet per minute (FPM). A restricted system measures 600 to 900 FPM. A severely restricted system reads under 600. We have measured Brooklyn brownstone dryers at 280 FPM, roughly 20 percent of healthy.

Airflow velocity at the exterior cap. We then measure FPM at the cap with the same cycle running. A healthy system loses very little velocity between collar and cap. A restricted system loses a lot. The ratio tells us where the restriction is — at the cap (hood or pest nest), in the run (compacted lint), or at the dryer (transition hose or lint trap area).

Static pressure at the dryer collar. A manometer measures the back pressure the blower is fighting. A healthy Brooklyn brownstone roof-vented system measures around 0.3 to 0.5 inches of water column. A clogged run can be 1.2 inches or higher. The blower is designed for roughly 0.6 inches maximum.

Cabinet temperature. Non-contact infrared thermometer at multiple points: top, front, side, and back near the blower. Healthy reads 100 to 110 degrees. Restricted reads 130 to 150.

Duct interior inspection. A borescope down the duct from the dryer end and, where possible, from the cap end. We document with photos and provide them as part of the written report.

Before and after photos. Every job gets a before photo of the lint we pull out and an after photo of the cleaned duct interior. This is how we differentiate from companies that show up, run a brush, charge a fee, and leave without opening the system.

The full diagnostic takes 20 to 30 minutes on top of the cleaning itself. We do not charge separately for it.

Pricing for diagnostic and cleaning

Pricing depends primarily on building type and run configuration. Full cost breakdown in the Brooklyn dryer vent cleaning cost guide. Summary for diagnostic-plus-cleaning visits:

Configuration	Diagnostic plus standard cleaning
Apartment, short run, wall-vented	$250-$400
Post-war condo, medium run	$275-$425
Single-family row house	$300-$500
Brownstone, roof-vented, accessible roof	$325-$575
Brownstone, roof-vented, parapet climb required	$400-$700
Pre-war co-op, dedicated shaft	$325-$600

The lower end of each range applies to standard cases: accessible cap, metal run, moderate lint load, no special access required. The higher end applies to harder cases: extreme lint load (more than two pounds removed), bird nest extraction, transition hose replacement, parapet ladder work, or code-compliance work like replacing accordion ducting with rigid metal.

The diagnostic is included in the visit. If we arrive and the system is in better condition than expected and does not need a full cleaning, we still charge a minimum visit fee of $175 for the diagnostic, documentation, and minor service work. Multi-unit discount of 15 to 25 percent off each additional dryer at the same visit. Call (718) 541-5567 for a quote.

The two signs that should trigger an immediate stop-using-it

If you take nothing else from this article, take these two. Most of the signs on this list are early warnings that you can act on in the next week or two. These two are not.

Burning smell during a cycle. Any kind. Stop the cycle. Unplug the dryer. Shut off the gas valve if it is a gas dryer. Do not run it again until it has been inspected. Smoldering lint is not a hypothetical risk. It is the specific physical condition that becomes a dryer fire, and once it is smoldering, it can ignite at any time.

Dryer cabinet painfully hot to the touch. If you cannot rest your palm on the top of the dryer at the end of a cycle without flinching, the dryer is running at temperatures that exceed its design range. The components inside are degrading, and the cabinet is hot enough that adjacent materials (drywall, baseboards, cabinetry) are being heat-stressed every cycle.

If you are seeing either of these, the dryer should not run another load. The cost of a service call is much lower than the cost of a fire, and it is much lower than the cost of replacing a dryer that has overheated itself into early failure.

FAQs

How often should I clean my dryer vent in Brooklyn?

For most Brooklyn homes, every 12 to 18 months. Brownstones with long roof runs should be closer to every 12 months. Small apartments with very short runs can sometimes go 24 months. Households with pets, large families, or daily laundry should go to 9 to 12 months. See the full schedule guide for a building-by-building breakdown.

Is a clogged dryer vent really a fire risk?

Yes. The U.S. Fire Administration estimates roughly 2,900 home clothes-dryer fires per year in the United States, with leading factor "failure to clean" cited in about a third of them. We have written more on this in our piece on Brooklyn dryer vent fires and how to prevent them. The risk is not the dryer itself. It is the heat backing up because the vent cannot move air, combined with the lint sitting against hot metal somewhere in the system.

Can I clean my dryer vent myself?

For a short run (less than 10 feet, single elbow, accessible cap) in a small apartment, a residential brush kit and a shop vac can do an adequate job, and we have customers who self-maintain. For a Brooklyn brownstone roof run, the answer is no. The runs are too long, the brushes are not long enough, the cap is not safely accessible without fall-arrest gear, and the consequences of a stuck brush head are severe.

My lint screen is always full of lint. Is that a good sign or a bad sign?

A lint screen with a normal amount of lint on it after every load is exactly what you want. That means the screen is doing its job and capturing lint before it reaches the duct. A nearly-empty lint screen is the bad sign — see Sign 5 above.

My dryer's manual says to clean the vent every year. Is that enough?

The manufacturer's recommendation is a floor, not a ceiling. In Brooklyn, with the long runs and the building stock, every 12 months is appropriate for most homes. For brownstones we recommend 12 months even on light usage.

Will a clogged vent damage my dryer?

Yes. The premature failures we see most often on dryers with clogged vents are: blower motor failure (from working against high static pressure), heating element failure (from cycling against high cabinet temperatures), and control board failure (from heat exposure). A dryer that should last 15 to 20 years can fail at 6 to 8 years on a chronically clogged vent. The cost of a new dryer is much higher than the cost of regular vent cleaning.

What about ventless heat-pump dryers? Do they need cleaning?

Yes, but the work is different and there is no exterior duct. The lint accumulates inside the dryer in a different way and the heat exchanger needs periodic cleaning. We have written more on this in the guide to condenser, ventless, and heat-pump dryers in Brooklyn.

My building's super says the vent was cleaned last year, but my dryer is still slow. Could the super's vendor have done a bad job?

It happens more than we would like. The cheap-and-fast version of vent cleaning is a leaf blower at the dryer end, no roof work, no measurement, no photos. It moves the loose lint around but does not remove the compacted lint at the cap or in the elbows. If your building is paying for an annual cleaning and your dryer is performing badly, ask for the before-and-after photos and the airflow measurements from the last visit. If they were not taken, the cleaning was inadequate.

Can a clogged vent cause my electric bill to go up?

Yes, noticeably. A clogged-vent dryer runs longer cycles and operates the heating element at a higher duty cycle. We have seen monthly electric bill increases of $15 to $40 a month attributable to a single severely clogged dryer vent in households that run 4 to 6 loads a week.

How long does a professional cleaning take?

Apartment with a short run: 45 to 75 minutes. Brownstone with a long roof run: 90 minutes to 3 hours. The variance is mostly driven by access time (parapet, ladder, hatch) and by what we find inside the duct.

Do I have to be home for the cleaning?

For interior work, yes, somebody over 18 has to be home to give us access. For roof and exterior work in some buildings, the super or a building rep can let us into the roof while you are at work, but we still need access to the dryer at the start and end of the visit. If you are in a co-op or condo, we will coordinate access requirements with your building staff in advance.

Will the cleaning be messy? Should I move things?

The duct interior is dirty. We bring HEPA-rated extraction equipment that captures the lint as we work, and we put down floor protection in the laundry area. The laundry room will be cleaner when we leave than when we arrived. You do not need to move anything out of the laundry room.

A note before you call

Most of the calls we get start with "I am not sure if this is really a problem, but..." That is exactly the call we want. The earliest version of any of these signs is the easiest to fix. By the time the dryer is shutting itself off or the cap is sealed shut, the work is harder, the lint load is heavier, and the risk has been higher for longer. We would rather come out for a 60-minute apartment cleaning today than a three-hour brownstone restoration after the high-limit has tripped twice.

If you have read this far and you have noticed any of the 11 signs, call us at (718) 541-5567 or book a visit online. We will measure airflow before and after, document everything with photos, and leave you with a vent system that runs the way it should. If the signs you are seeing are the burning-smell or hot-cabinet variety, please stop using the dryer until we have looked at it.

For the full picture of how we work, the companion read is the complete Brooklyn dryer vent cleaning guide. For the fire-risk side, the Brooklyn dryer vent fires post is the one we want every property owner in the borough to have read.