Many homeowners take their home’s ducts and chimneys for granted. We are more likely to repair a noisy car exhaust than worry about maintaining a home’s exhaust system, air ducts, and heating equipment. After discussing their home’s air quality with our service professionals, many homeowners are genuinely interested to know more. Here are the answers to the questions we’re commonly asked about air duct, chimney and dryer vent cleaning.


Answers to Frequently Asked Questions

Many homeowners take their home’s ducts and chimneys for granted. We are more likely to repair a noisy car exhaust than worry about maintaining a home’s exhaust system, air ducts, and heating equipment. After discussing their home’s air quality with our service professionals, many homeowners are genuinely interested to know more. Here are the answers to the questions we’re commonly asked about air duct, chimney and dryer vent cleaning.






Heating & AC Duct Cleaning Q&A

Q. Why should I bother to clean my air ducts?

A. Most people clean their heating and air conditioning ducts because they know the air they breathe affects their health. A full 50% of all illnesses are either caused or aggravated by polluted indoor air. The EPA has actually found that air inside many homes and office buildings is more polluted than outdoor air in heavily industrialized areas. When you realize that the average person spends 90% of their time indoors, it’s easy to see the need to clean your ducts and improve your home’s indoor air quality Cleaning your ducts will:

  • Reduce the airborne allergens in your home
  • Remove potentially dangerous mold and other contaminants
  • Improve air flow and reduce utility bills
  • Eliminate the need to dust your furniture as often
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Q. My house is new. Should I clean my ducts?

A. Most new homes have loads of construction debris in the air ducts–everything from drywall dust to half-eaten Big Macs tossed by construction workers. This material blocks airflow, breeds microbes and even attracts rodents. I immediately cleaned the air ducts in my own home after completing a remodeling project. Return to top of Q & A Page


Q. I was told my heating ducts can’t be cleaned?

A: Your system probably has flex duct–a popular duct material due to its low cost and insulating properties. Many cleaners refuse to clean flex duct because their high pressure air sweeps will damage it. Fortunately, the patented Rotobrush equipment employed by Chadds Ford Chimney Sweeps was designed to efficiently clean flex duct without damaging its soft internal lining. Return to top of Q & A Page

Q. What type of air ducts do you clean?

A. Our equipment efficiently cleans the heating/AC ducts in all residential and many commercial buildings. We cannot clean the larger ductwork found in some commercial and industrial buildings.Return to top of Q & A Page


Q. What kind of duct cleaning equipment do you use?

A. Our advanced Rotobrush equipment combines a soft rotating brush that is attached to a high powered HEPA vacuum nozzle. The Rotobrush is the only duct cleaning system that simultaneously brushes and vacuums at the point of contact. We can even attach a remote video camera that will guide the brush into corners and areas that less advanced cleaning systems might miss. Return to top of Q & A Page


Q. Do you use a deodorizer for air ducts?

A. After your ducts are cleaned, we fog the entire system with EnviroCON. This product is registered with the EPA for use in occupied spaces and is commonly used in hospitals, nursing homes, restaurants, hotels and office buildings. It eliminates odors by destroying the microorganisms that cause the odor. EnviroCON performs exceptionally well–in one instance we were able to totally eliminate the foul odor caused by a bottle of baby formula that fell into a heating duct. Besides destroying odor causing bacteria, EnviroCON is also effective against mold, mildew fungi and algae.Return to top of Q & A Page


Odor Eliminating Product: EnviroCON
Manufacturer: Bio-Cide International, Inc.
Active Ingredient: Chlorine Dioxide
Registered by the EPA: Yes
EPA Rating: Category III
Application: Hand-held fogger or air-driven sprayer
Safe to use in occupied spaces: Yes
Eliminates odors associated with: Bacteria, mold, mildew, fungi, yeast, algae
Controls pet odors: Yes
Controls smoke odors: Yes
More information: Go to Bio-Cide International website

Q. How often should I clean my heating and air conditioning ducts?

A. Most industry professionals recommend an inspection every 2-years and cleaning every 5-7-years, but these are just guidelines. Many factors–from the presence of pets to the type of furnace filter you use–impact cleaning frequency. We recently inspected a heating/AC system that was last cleaned 8-years-ago and was still in pristine condition.  Return to top of Q & A Page


Q. How much does air duct cleaning cost?

A. The EPA says that “duct cleaning services typically–but not always–range in cost from $450 to $1000 per heating and cooling system, depending on the services offered, the size of the system to be cleaned, system accessibility, climactic region, and level of contamination” and type of duct material.
Consumers should be especially leery of any duct cleaning company that offers an extremely low price. It’s common in our service area to see coupons that advertise whole house duct cleaning for $84.99 or even $69.99. Are these low prices too good to be true? They certainly are when you consider that it takes a two-man crew anywhere from 4-12-hours to properly clean a home’s air ducts and service vans consume gasoline at a rate of 8-10-miles-per-gallon.
A low advertised price usually means one of two things: 1) A “blow-and-go” air duct cleaning company that rushes through the job and cleans just the first few feet of each duct; 2) a “bait-n-switch” operator that may persuade the consumer into unneeded services with and/or without their permission. Return to top of Q & A Page


Q. Will air duct cleaning fill my house with dust?

A. Not if you hire Chadds Ford Chimney Sweeps. First, we don’t use accident prone compressed air cleaning methods. Second, we take extraordinary dust-proofing precautions (like hand vacuuming register boots) that less picky cleaners don’t bother doing.

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Chimney Cleaning & Repair Q & A

Q. How often should I have my chimney cleaned?

A. The Chimney Safety Institute of America recommends that you have your chimney checked every year. Even if a chimney is seldom used or exhausts a clean burning natural gas appliance, it could be blocked with an animal nest or the structure could have deteriorated to the point where the chimney is unsafe to use.

Gas burning device chimneys should be inspected every year.

Oil furnace chimneys should be inspected annually and cleaned as needed.

Wood burning fireplaces should be inspected annually and cleaned as needed.

Woodstoves are typically used more frequently than fireplaces. Many woodstove chimneys actually require cleaning twice a year.

Q. What does dust-free HEPA cleaning mean?

A. We actually clean your chimney with metal or nylon brushes that dislodge soot and creosote. The HEPA (high efficiency particulate air) refers to the high-powered, dual-filter Rovac Systems vacuums we employ to keep soot from entering your living quarters during the cleaning process.

Our Rovac vacuums feature 3 high powered motors that produce up to four times as much air flow as the best commercial vacuums. And the Rovac’s twin filters trap smaller soot particles than other chimney vacuums. This extra power and filtering efficiency is especially welcome when we’re dealing with the ultra fine soot produced by an oil furnace, but it also provides an extra measure of safety when we’re cleaning your fireplace or wood stove flue.

We advertise our dust-free HEPA cleaning process because most chimney sweeps use less advanced vacuums that are not HEPA rated. Homeowners have even reported that some chimney sweeps in this area employ ordinary wet/dry shop vacuums that can allow soot to enter the home.  Return to top of Q & A Page


Q. How long does it take to clean a chimney?

A. We have two-men crews that will spend approximately 45-60-minutes sweeping a masonry fireplace or woodstove chimney. A prefabricated fireplace chimney will take slightly less time, and a walk-in fireplace can take 2-3-hours. Return to top of Q & A Page


Q. Should I cover my furniture and rugs?

A. There’s really no need for you to cover anything. We take special precautions to make sure soot will not damage your valuable home furnishings. These steps include everything from spreading plenty of clean drop cloths to using only true HEPA rated vacuums. Return to top of Q & A Page


Q. What’s the best time of year to clean my chimney?

A. Spring to early-Summer is the best season to clean a chimney for several reasons:

Any problems uncovered during cleaning/inspection can be repaired in time for the next burning season.

You’ll prevent the foul odor that occurs when hot, humid summer air reacts with creosote in a dirty chimney.

You can usually get the job done right away instead of waiting weeks for an appointment during the busy Fall/Winter months.


Q. When I bought my townhouse, the realtor said it has a zero maintenance fireplace that doesn’t need cleaning. Is this true?

A. No. Every wood burning fireplace requires regular cleaning. Your fireplace and chimney is probably a prefabricated model. Prefabricated or factory built metal chimneys are sometimes called “zero clearance,” which means the double walled metal flue is insulated between the layers and can be safely abutted close* to your home’s wooden structure. Return to top of Q & A Page


“Zero Clearance” is a misnomer because virtually all prefabricated fireplace/chimneys need to be placed a certain distance away from combustible materials like wood framing.


Q. Do those chimney cleaning logs work?

A. It should be stated at the outset, that no chimney cleaning (or anti-creosote) product is a substitute for professional cleaning and inspection. Most anti-creosote products only make it easier to remove creosote from a chimney. They are akin to an oven cleaner that loosens baked-on grease but still requires scrubbing to actually remove the grease. It’s also necessary to have your chimney inspected each year to detect any blockage or unsafe condition.
Our limited experience with chimney cleaning logs wasn’t good. A homeowner with a serious case of glazed creosote tried to remove it with several plastic tubes of an anti-creosote product as well as two chimney cleaning logs. When we returned, these products had only transformed a tiny portion of the glazed creosote (less than 10%) into a brushable state. Most of the creosote was still as hard as rock candy and firmly stuck to the masonry.
The anti-creosote product that seems to do the best job of transforming glazed creosote into a substance that we can remove with wire brushes is CreAway–a product manufactured by Saver Systems. CreAway is a powder that is shot into the top of the fire via a squeeze bottle. It then travels up the flue and reacts with heat to make glazed creosote break it’s bond with the chimney. Several applications are required before the Sweep can easily remove the creosote. Caution should be exercised by any homeowner using this product because it is extremely irritating to the eyes.

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Q. Do I need to install glass doors on my fireplace?

A. A glass firescreen isn’t essential, but it is a nice addition to a wood burning fireplace:

The doors can make it easier to start a fire by channeling fresh air to the bottom of the fire. Shut the doors and open the vent at the bottom when you start the fire.

Closing the doors and the damper when the fireplace is not being used will prevent more heat loss than just a closed damper.

Finally, and most important, the doors let you retire for the evening while the fire is still burning. Just close the doors and keep the damper open. The fire will safely die without letting heated air escape out the chimney all night

Q. My fireplace smokes. Will cleaning the chimney solve this problem?

A. Many things (from not opening the damper to a poorly designed chimney) will cause smoke to enter the living quarters. In some cases, heavy creosote accumulation in the flue can reduce the flue size enough to cause smoking. A good chimney cleaning will correct this smoking problem. Return to top of Q & A Page


Q. What causes creosote?

A. Creosote is a natural byproduct of burning wood. Wood smoke is comprised of steam and vaporized carbon particles that form creosote when they condense and solidify on the relatively cool surface of the smoke chamber and flue.


Creosote is classified into three stages:

  • Stage 1 Creosote: A black, dusty substance also known as soot.
  • Stage 2 Creosote: Usually black, light and crunchy in weight and texture.
  • Stage 3 Creosote: Hard, shiny and glazed. Looks like glossy black paint.

While all creosote is highly flammable, Stage 3 Creosote causes the most trouble because it is extremely difficult to remove and is usually found in heavy quantities. In our experience, the main causes of Stage 3 Creosote are burning unseasoned wood or having an older woodstove/fireplace insert that vents into a too large flue. Let’s explore both of these factors in a bit more detail.
Wet, unseasoned wood produces gobs of creosote because it burns relatively cool. A cool burning wood fire has three negative byproducts: 1) the wood burns less completely and the smoke contains more creosote generating carbon particles than smoke from a hot fire; 2) the cooler smoke chamber and firebox add to the problem by making more of the smoke condense into creosote; 3) the cooler fire does not produce as much draft as a hot fire so the smoke moves slower up the chimney giving it more time to condense and form deposits. Wet wood is responsible for most of the Stage 3 Creosote we encounter.
Another proven generator of Stage 3 Creosote is a wood stove or fireplace insert that vents directly into a large flue. A woodstove with a 6″ diameter exhaust venting into a 12″ x 12″ flue is a typical example. The large flue remains relatively cool and we have a repeat of some of the “wet wood factors” discussed above. First, the draft in the cool flue is weak and the smoke moves slowly, having plenty of time to condense into creosote. Second, the low temperatures also stimulate condensation/creosote formation. The two factors are compounded by the proclivity of some stove owners to burn a slow, relatively cool fire to stretch their wood supply. How much creosote can a wood stove produce? We actually removed over 100-lbs of creosote from one chimney! Return to top of Q & A Page

Q. What makes my fireplace stink in the summer?

A. The sour wood smoke odor you smell is creosote inside a dirty chimney reacting with hot, humid summer air or rain entering the chimney. The best way to eliminate this odor is to clean the chimney to remove the creosote. Installing a chimney cap to deflect rain may also be required. In cases where creosote has permeated the masonry, a deodorizer can be applied to mask any remaining smell.Return to top of Q & A Page


Q. My fireplace has cracks in the ceramic panels. Are these dangerous?

A. The refractory panels that line the firebox of a prefab fireplace often have hairline cracks caused by the repeated heating and cooling of the material. These fine cracks are not dangerous because there is metal behind the refractory panels. You should replace the panels if the cracks are larger than 1/16-inch or when the refractory crumbles and is missing significant chunks. Return to top of Q & A Page


Q. The last chimney sweep I hired didn’t remove the black stains from the brick in my fireplace. Is this standard procedure?

A. While we often say that we “clean chimneys,” in the strict sense of the word we actually sweep chimneys. A chimney sweep will eliminate heavy deposits of creosote that could fuel a chimney fire, but it isn’t necessary (and it would be cost prohibitive) to remove the tiny particles of soot embedded in the masonry pores inside a fireplace. The difference between cleaning and sweeping a chimney is similar to wet mopping versus sweeping a floor.


Homeowners will sometimes hire us to remove stains from brick or stone fireplace facings, but there is absolutely no need to spend the time (and our customers’ money) to remove this type of embedded stain from the inside of a fireplace. Return to top of Q & A Page


Q. My chimney has ugly rust stains running down the side. What causes this?

A. It sounds like you have a prefabricated chimney with a rusted chase cover. The top of the housing that is built around many prefab chimneys has a flat metal roof called a chase top or chase cover. Homebuilders nearly always use galvanized steel chase covers that begin to rust-out after about 15-years. Eventually, the corrosion will eat through the metal and cause a serious leak. We routinely replace these rusted-out covers with stainless steel chase covers that will last a lifetime. Return to top of Q & A Page


Q. What is the best wood to burn?

A. Your main objective is to acquire firewood that is dry and seasoned. While hardwoods generally have more heat value than softwoods, burning unseasoned hardwood produces a lot more dangerous creosote than burning seasoned softwood. First, make sure any wood you burn is adequately seasoned. Then worry about the species of wood as shown in the following table that depicts heat value (in millions of BTUs per cord) for some common wood species:

Wood Species BTU’s
Hickory 27.5
Oak (White) 25.5
Maple (Sugar) 24.0
Oak (Red) 24.0
Ash 23.5
Birch 20.3
Douglas Fir 20.5
Elm 19.5
Poplar 14.7
Pine 14.5
Balsam Fir 14.3

You should never burn pressure treated lumber, painted wood or plywood. Extreme care should be taken in burning pine because it contains pockets of pitch that will “explode” and throw sparks. Return to top of Q & A Page

Q. We cut down some trees on our property. How long does it take to season wood?

A. Wood that is properly prepared will take a minimum of 6-months to dry to the 18-25% moisture content range that’s ideal for firewood. Proper preparation means:

Cut the wood to fireplace or woodstove length.

Split the wood. This step is critical because tree bark traps moisture inside.

Stack the wood in a single row with the bottom row elevated above the damp ground. Ideally, the top should be covered, but the sides should be open to permit air flow.

Q. How can I tell if the firewood I’m buying is seasoned?

A. Dry, seasoned wood will have cracks in the ends. In general, the bigger the cracks, the drier the wood. The color of the wood is more difficult to interpret. While seasoned wood is typically darker or grayer than green wood, splitting a piece of seasoned wood also reveals light, “fresh looking” wood. The best indicator of whether wood is seasoned is checking the ends for cracks that occur during the drying process. Return to top of Q & A Page

Q. What is a cord of wood?

A. A full cord is a stack of wood that measures 8-foot wide x 4-foot high x 4-foot deep. but in our region most firewood suppliers offer face cords that measure 8-foot wide x 4-foot high x 2-foot deep. The distinction between a full cord and a face cord (50% of a full cord) is important to know when you’re comparing firewood prices. Return to top of Q & A Page


Q. My woodstove sometimes smokes when I first light it?

A. Cold, dense outside air can form a “plug” in the flue and cause the problem you describe. While this can happen in both fireplaces and wood stoves, it’s more common in the latter. The solution is to pre-warm or prime the flue before you start a fire. If you have a woodstove crumple up newspaper into several fist-size balls, place in the stove and light. If you have a fireplace, loosely roll newspaper, light it and let it burn near the open damper for 10-15 seconds. In both instances, opening a nearby window until the fire is venting properly can also help create a good updraft. Return to top of Q & A Page


Q. Doesn’t the flue liner protect my house during a chimney fire?

A. A chimney fire generates high temperatures than can “melt” mortar, crack tiles, cause flue liners to collapse and damage the outer masonry material. When flue liners crack and mortar is displaced, flames can reach the combustible wood frame of a house. One chimney fire may not harm a home. A second can burn it down. Enough heat can also conduct through a perfectly sound chimney to ignite nearby combustibles. Return to top of Q & A Page

Q. How can I prevent a chimney fire?

A. The National Chimney Safety Institute recommends the following steps to avoid a chimney fire:

Use seasoned woods only (dryness is more important than hard wood versus soft wood considerations)

Build smaller, hotter fires that bum more completely and produce less smoke

Never burn cardboard boxes, wrapping paper, trash or Christmas trees; these can spark a chimney fire

Install stovepipe thermometers to help monitor flue temperatures where wood stoves are in use, so you can adjust burning practices as needed

Have the chimney inspected at least once a year and cleaned as needed

Q. What should I do if I have a chimney fire?

A. Any chimney fire has the potential to ignite your home and take lives. A chimney fire is extremely dangerous.

Get everybody out of the house and call the fire department (Call 911)

If you have a chimney fire extinguisher, use it.

Close any air inlets on stoves and glass doors on fireplaces.

Have the chimney cleaned and checked by a chimney professional before you use it again.

Q. I keep a chimney fire extinguisher next to my fireplace. Why should I bother to get my chimney cleaned?

A. A chimney fire extinguisher is no substitute for proper chimney maintenance. First, your chimney could have a blockage that prevents the fire from exhausting properly. So even if your fireplace has a gas fire log, deadly carbon monoxide could invade your home.


Second, not all chimney fires are apparent to a homeowner. Some chimney fires burn explosively, alerting homeowners with a rumbling sound like a train or low flying plane. Other chimney fires burn slower and can go unnoticed. But even a slow burning chimney fire produces temperatures that can cause significant damage to the chimney and combustible parts of the house. Return to top of Q & A Page

Q. Isn’t a chimney fire a good way to clean a chimney?

A. Absolutely not! Deliberately starting a chimney fire could burn your house down or force you to spend thousands of dollars to repair your chimney. Besides, when creosote deposits burn, they can expand and leave a puffy residue that can actually block the flue.  Return to top of Q & A Page


Q. I have an oil furnace. Should I have this chimney cleaned?

A. Yes. Oil soot is extremely corrosive and can seriously damage a chimney flue. A bi-product of oil combustion is sulfur dioxide that turns into sulfuric acid when it encounters moisture. This acid erodes terra-cotta clay flue liners, causing gaps in the flue where fumes can escape into living space, or causing the flue liners to collapse and block the vent completely.


Given that an oil furnace can produce carbon monoxide, it’s extremely important to have your oil furnace flue inspected each year and cleaned if soot deposits are present.


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Q. I heat with natural gas. Should I have this chimney cleaned?

A. Natural gas usually leaves little residue in the chimney to sweep, but it’s important to regularly inspect a chimney that serves a natural gas appliance like fire logs, a gas stove or central heater due to the danger of carbon monoxide poisoning.


Natural gas combustion can produce carbon monoxide. When your gas furnace and chimney are working properly, the resulting fumes are mainly carbon dioxide and water vapor. But if your furnace doesn’t get enough oxygen, either because the house is too tight or the chimney isn’t functioning properly, carbon monoxide is produced. You can’t smell this deadly gas, and while carbon monoxide detectors are readily available, how comfortable do you feel entrusting your life to a $30 device that was probably manufactured in China?


One of our customers who has gas fire logs that burn propane called us because soot was entering her living room (Propane, unlike natural gas, often produces soot.). A chimney inspection revealed that a lightning strike cracked the entire flue from top to bottom preventing the chimney from drafting properly. Our customer was totally unaware of the lightning strike. If her fire logs were natural gas and the carbon monoxide detector did not work, this would have been a disaster.


Today’s high-efficiency gas furnaces also pose special problems. The fumes they produce are cooler and contain high levels of water vapor, which cause more condensation than older models. Since these vapors also contain chlorides picked up from house-supplied combustion air, the flues are subjected to more corrosive conditions than before and can quickly deteriorate or plug up completely.


Any chimney that vents the exhaust of a natural gas burning appliance–furnace, water heater, fire logs, etc.–should be inspected each year for blockages and other dangerous conditions. Never assume that your chimney is safe. Return to top of Q & A Page

Q. What are the pro’s and con’s of ventless fire logs?

A. The following table should help clarify the key differences of vented fire logs versus the newer ventless models:


Vented Gas Firelogs Ventless Gas Firelogs
– Tall, dancing, realistic flames like a wood fire – Lower, less realistic flame
– Most of smell goes up chimney – Odor produced that bothers some people
– Most of heat goes up the chimney – High heat output can warm room
– Uses slightly more gas – Slightly less gas usage
– Does not require CO2 detector – Requires a CO2 detector
– Adds moisture to air, can cause mildew
– Cannot burn too long–will deplete oxygen
– Not legal everywhere. Check local codes



Q. A heating contractor inspects my furnace and hot water heater every year. Doesn’t this mean my chimney is safe?

A. Not necessarily. A heating contractor’s inspection usually stops at the beginning of the flue or chimney base. Problems inside the flue can remain undetected and subject you and your family to the risk of carbon monoxide poisoning.  Return to top of Q & A Page


Q. I can hear birds in my chimney. What should I do?

A: The birds you hear are chimney swifts. They can fly vertically, which allows them to enter your chimney and nest. Chimney swifts are migratory birds that are protected by federal law, so we cannot remove them. If you wait 3 weeks, the babies will be able to fly and the birds will leave. Then we can come and clean-out the fire hazardous nesting material from your chimney. We can also install a chimney cap to prevent future nesting. Return to top of Q & A Page

Q. Why do I need a chimney cap?

A. A chimney cap does everything from preventing water damage to keeping the flue clear of fallen leaves, but repelling disease carrying birds and animals is one of its most important roles. Animal invasion through the chimney is far more common than what you might think. We actually find a dead bird or dead squirrel in approximately one of every four chimneys that we clean. The last thing any homeowner needs is a soot covered (and potentially rabid) squirrel scampering through the house.

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Q. My mother never cleaned her dryer’s vent. What’s the big deal today?

A: In the past, clothes dryers were usually located near an exterior wall. This resulted in a very short vent that collected minimal lint. Today’s home designs often place the dryer in a central location that requires a long vent run. These longer vents are especially prone to lint buildup which reduces dryer performance and can ultimately cause a fire.


There’s also a trend to locate washers and dryers on the second floor, placing the dryer’s exhaust hood high on a sidewall or on the roof. These higher locations are more prone to invasion by nesting birds than an exhaust hood located near the ground.

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Q. How does a dryer fire start?

A. Dryer vents accumulate lint just like plaque deposits that form in human blood vessels. The lint reduces air flow and increases clothes drying times. The lint can build-up to the point where it blocks the dryer exhaust and causes serious overheating in the dryer. When this happens, the dryer’s high temperature safety switch will repeatedly cycle on and off. Ultimately, the safety switch can fail, allowing the highly flammable lint to ignite. Investigators have found that just a single spark can ignite lint. We’ve seen dryers whose housings were packed with lint–often, the lint is charred black and a heartbeat away from starting a house fire!. Return to top of Q & A Page


Q. Can a clogged dryer vent lead to carbon monoxide poisoning?

A. Only if the dryer operates on natural gas instead of electricity.. Return to top of Q & A Page

Q. What are the warning signs of a blocked dryer vent?

A. The first sign of trouble is nearly always long drying times–especially of heavy items like jeans and towels. The most common warning signs of a dryer vent that requires immediate attention are:

Clothes (especially heavy items like jeans and towels) take too long to dry.

Clothes are extremely hot when finally dry.

The top of the dryer is hot to the touch.

The flapper valve at the exhaust hood does not open fully. Return to top of Q & A Page

Q. I always clean the lint filter. Doesn’t this keep the vent clean?

A. Cleaning the lint filter with every load helps, but even the double wall lint filters found on some European dryers don’t totally prevent lint buildup in the vent. There’s also the common problem of bird’s nesting in the vent. We actually removed 3-4 bushels of straw nesting material from a single dryer vent. Return to top of Q & A Page


Q. Are fabric softener sheets dangerous?

A. Supposedly a dryer repair man (identify unknown) told a homeowner (identity unknown) that fabric softener sheets leave an invisible film on the lint filter that causes dryer fires. Frankly, we don’t know if dryer sheets deposit an invisible film on lint filters, but this story seems to have the characteristics of an urban legend. Consumer Reports, which has tested hundreds of clothes dryers, stated that the sheets might leave a film over time, but says it’s doubtful that such a film would alone lead to a fire. Return to top of Q & A Page

Q. Birds keep making nests in my dryer vent. How can I keep them out?

A. Dryer vents are a convenient nesting spot for birds. The birds are attracted to lint as a nesting material–eventually one of the birds will decide to stay. We can install a bird guard (a plastic cage that covers the vent exhaust) to prevent birds from entering the vent. Return to top of Q & A Page


Q. My dryer is slow. How can I tell whether to call the dryer repairman or the dryer vent cleaner?

A. Clothes dryers are very reliable, and excessive drying times usually indicate a blocked vent. A simple way to identify why your clothes are drying slow is to detach the vent and dry a load of wash. If the dryer is still slow, the problem is inside the dryer. But if the drying time is noticeably quicker, you need to have your vent cleaned.  Return to top of Q & A Page


Q. How often should I clean my dryer vent?

A: A variety of factors (from frequency of use to vent length) influence how often a dryer vent should be cleaned. Long drying times are the first signal that the vent is clogged. Most dryer vents or ducts should be cleaned-out every year. Some experts actually recommend cleaning them every 6-months.Return to top of Q & A Page

Q. My dryer vent is only 6-feet long. Can’t I clean it myself?

A. Yes, it’s relatively easy for most homeowners to clean a short, flexible vent. Just make sure to also clean the dryer itself. We typically spend 20-30 minutes cleaning the dryer’s internal ductwork and housing. It’s important to remove this lint because every dryer fire starts in the dryer before it spreads to the dryer vent. Return to top of Q & A Page


Q. My dryer vent just blows into the attic. Can this hurt anything?

A. We occasionally find a dryer vent in a town house that just dumps its moisture laden exhaust into the attic. Given that a typical dryer load has 1/2-gallon of water, This problem should be corrected ASAP because water damage, even mold and mildew, can develop. There’s also the opposite problem of a fire starting when the lint dries into a highly flammable state.  Return to top of Q & A Page


Q. The dryer exhaust in our townhouse comes out of the roof. Is this OK?

A. In our opinion, “stupid” is a pretty fair assessment of venting a clothes dryer exhaust through the roof. Your home’s builder has made it impossible for you to perform necessary inspections of the exhaust hood. You should, for example, regularly inspect the hood to gauge air flow or the presence of nesting birds.


An additional problem in colder climates happens when the moisture laden dryer exhaust passes through the unheated attic space in winter, condenses and forms a blockage of sopping wet lint. While the exhaust duct could be insulated to prevent this problem, we’ve yet to see a builder that bothered to insulate the dryer duct. Return to top of Q & A Page

Q. We’re relocating our laundry room. What’s the maximum length for a dryer vent?

A. First, consult the installation instructions provided by the dryer manufacturer. If this information is not available, the International Residential Code states that the duct (not including the transition duct from the dryer to the wall) should not exceed 25-ft. Moreover, this maximum length should be reduced 5-ft for every 90-degree bend and 2.5-ft for every 45-degree bend. Return to top of Q & A Page


Q. What do you think about using PVC pipe for a dryer vent?

A. PVC pipe should never be used as a dryer vent. Few people realize that when air flows over plastic, it generates static electricity. Lint is attracted to the static electricity, and PVC dryer vents usually have extremely thick lint deposits. Metal is the best dryer vent material.


Q. My dryer vent broke and fixing it will cost a fortune because it runs above a finished ceiling. Do the clothes dryer lint traps they sell at hardware stores work?

A. Lint traps that use a water reservoir to trap lint particles are marketed as a replacement for conventional dryer vents. They cost around $15 and can be found at local hardware stores and home improvement centers. These devices do a fairly good job of trapping lint, but shoot hot, moisture laden air into your home which will increase your air conditioning bills in the summer and might even cause a mold problem. The hot exhaust also contains chemicals used in detergents and fabric softeners. While a lint trap is an economical solution to a broken vent, it’s not an ideal solution.