Dryer vent cleaning is usually a pretty routine event: the technician inserts a tool through the vent line from the outside and feeds it through to the back of the dryer, then pulls the tool out, extracting the lint with it. But every once in a while our technicians encounter a particular job that is not so easy, or so routine.
In March 2019 a homeowner in Maple Grove contacted us for a routine dryer vent cleaning. His dryer was not working efficiently and was taking much longer than usual to dry clothes. This is a frequent symptom of a clogged dryer vent, so our technician did not expect to find anything out of the ordinary. The dryer vent exhausted out the second floor of the home, about 15 feet up, making the total vent line about 30 feet in length. Longer vent lines often harbor more lint than shorter ones—for example, those that vent straight out the back wall.
The first order of business for our tech on this job, as with any dryer vent cleaning, was to vacuum the machine's lint trap compartment with a crevice-tool vacuum attachment. This step removes any debris that sneaked past the lint trap. He then eyeballed the back of the dryer to ensure all of the connections were secure. With those two tasks complete, he ascended the ladder 15 feet up to the outside vent.
Having turned the machine on "air dry" before leaving the laundry room, the technician expected to observe at least some air flow exiting the outside vent, but there was none at all. For this reason he assumed he was dealing with a 100% blockage in the form of a dryer vent clog. This is the number one reason for restricted air flow through a dryer vent line.
His tool of choice is a reverse-blowing spinning skipper ball attached to the end of an air snake. This he feeds into the vent line through the outside vent, where warm air (and some lint) typically exhausts. He expected to meet some resistance in the form of a clog, but he soon heard the skipper ball reach the back of the dryer, at which point he realized his first assumption may have been incorrect. On pulling the tool back toward him, a good deal of lint was expelled, but not as much as expected for a clog capable of completely restricting air flow. He inserted and retracted the tool several times until he was confident all of the lint was removed from the vent line.
Now certain that the issue was not a clogged vent line, he proceeded downstairs and had a closer look at the machine itself. Pulling the machine away from the wall, he noticed there was an exceptional amount of lint behind it. He further noticed that the portion of the vent line that normally extends from the back of the dryer across the bottom of the unit and connects to the fan was disconnected, sitting idle and useless in the bottom of the machine, enveloped in a gray cloud of combustible lint.
This particular dryer vent disconnect was unusual in that everything appeared, from the outside, to be appropriately connected. Additionally, the location of the disconnect, inside the dryer itself, is relatively rare; often disconnects occur further down the vent line, sometimes behind wall cavities or inside the attic.
Disconnects in the dryer itself pose a particular danger in that instead of lint building up down the vent line, removed from the machine and its heating element, in this case it builds up inside the dryer itself. Lint is highly combustible and easily airborne, so one can imagine how its blowing around inside the dryer near the heating element would be extremely problematic.
The first thing the technician set about doing was cleaning out all of the lint from inside the dryer, with an industrial vacuum. The photo above was taken when that process was nearly complete. Once the lint was thoroughly removed, he easily reconnected the missing portion of the vent line, confident that after doing so, excellent air flow would be established.
He was correct.
Having your dryer vent regularly cleared of lint and any blockages serves several purposes, primary of which is to minimize the fire hazard created by a buildup of lint. Doing so also improves the machine's efficiency, by increasing the air flow necessary for it to do its job.
But the often overlooked or unanticipated benefit of dryer vent cleaning is the discovery of these vent line disconnects, which typically occur in places where they can't be seen. Left unaddressed, they wreak havoc inside the home, exhausting warm, moist air into spaces where it surely doesn't belong.
Once corrected, the vent line exhausts fully outside, where the warm air, moisture, and bits of lint quickly disperse and harm nothing, as intended.
Wanna dig deeper? Download our free tipsheet: 5 Questions to Ask Before Hiring a Dryer Vent Cleaning Company.
Many thanks to our technicians Ben S and Roy S for lending their expertise to this article.
Your HVAC system relies on good air flow to work its magic: heating, cooling, and ventilating your home. When your furnace is choked with dirt, your flue blocked with animal nesting, or your dryer vent clogged with lint, these systems are hindered. At best the associated system loses efficiency, at worst you risk a house fire or the backup of toxic gases into your home
Let's take a look at how proper air flow affects the smooth functioning of each of the HVAC (Heating, Ventilation, and Air Conditioning) systems. We'll include the dryer venting system here, though not strictly considered part of the HVAC system. (It does feature a vent, after all, and serves to exhaust heated air outdoors.)
Air flow creates draft in your chimney
Your chimney relies on the process of draft to maintain combustion and to safely vent its byproducts from your home. This includes not only your fireplace flue but your furnace, water heater, and boiler flues as well. Via the process of draft, warm air and the smoke or gases it carries from the source of combustion, moves up through the flue and is exhausted outside the house, often onto the roof. Any kind of blockage or other hindrance will impede air flow and prevent draft.
Without draft, of course, the necessary sequence of events will not unfold, at which point back-drafting can occur. In the case of a fireplace chimney, this will result in smoke coming back into the home rather than exiting the chimney. In the case of a utility flue (furnace, etc.), this will result in toxic gases, such as carbon monoxide, backing up dangerously into your living space.
Air flow carries warm air and lint away from your dryer
As your clothes dryer spins and fluffs and dries, the hot air generated by the machine is pushed out the back of the unit and through the dryer vent line, where it safely exhausts outside. Over time, as tiny bits of lint are deposited within the vent line, air flow slowly becomes restricted. Restricted air flow begets restricted air flow; that is, the more lint that is deposited, the more air flow is restricted, in turn leading to more buildup, until air flow is choked off completely by a dryer vent clog.
Once a dryer vent clog has formed and air does not flow freely, several things can happen. The best-case scenario is that your dryer's efficiency is reduced and takes longer to dry clothes, or it simply shuts down. The worst-case scenario is that the heat, having no escape, builds up inside the vent line and ignites the lint, causing a fire. For this reason, no dryer vent cleaning job is considered complete until good air flow has been observed from the outside exhaust vent.
Air flow through the air conditioner's A-coil transfers heat
Your A-coil, or evaporator coil, is one of the indoor components of your air conditioning system. Its function, by way of a series of refrigerant-filled tubes, is to absorb heat, thus cooling your indoor air in the summer. The exterior of the A-coil consists of a series of small, tightly spaced fins that help this process. Because these fins usher air toward the coil, when they are dirty or clogged the entire process is interrupted.
But the ill effects of poor air flow through the A-coil are not limited to your air conditioning system. Because all air that circulates through the HVAC system passes through the A-coil—whether it is your furnace or the AC that's running—a clogged evaporator coil has the potential to hamper not only the cooling of your home but its heating as well, and to drive up utility bills. Dirty components equal restricted air flow equals reduced efficiency equals higher energy costs. You get the picture.
Air flow through the furnace generates heat
Your furnace's job is to pull air from the return air ducts, warm it, and push the warmed air out through the supply ducts into your living space. Proper air flow is of course critical to this process, from beginning to end and back around again. Here are some points at which it is especially vital.
Maintain proper air flow with HVAC system cleaning
If you've read this far you probably don't need convincing that proper air flow is critical to the smooth functioning of your HVAC system. Any hindrance to adequate air flow in the form of dirt or debris can create havoc and lead to equipment breakdowns.
HVAC cleaning calls into action an arsenal of specialized tools (rotary brushes, air snakes, tentacled air whips, high-pressured air triggers, industrial vacuums) and technician expertise to rid the system of component-clogging dirt and debris. The result is a system that functions more smoothly and efficiently, performing its task in less time and using less energy to do so.
Just as our lungs and respiratory systems need unobstructed, smooth intake and exhalation of air to function as they should, so must our HVAC systems be able to "breathe" freely in order to do their best work for us.
Wanna dig deeper? Explore our HVAC cleaning service pages, including a detailed description of the cleaning process and tools utilized for each system.
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Many thanks to our technician Roy S. for lending his expertise to this article.
And why is it necessary?
An annual chimney sweep is beneficial in a number of ways, most importantly because the process removes creosote buildup from the inner walls of the chimney. Creosote, which is a sticky tar-like substance that adheres to the inside of the chimney, is highly flammable and requires regular removal in order to prevent chimney fires. Even if you do not burn wood in your fireplace regularly, the chimney is still susceptible to blockage from animal nests, the debris from which could easily ignite when you do start a fire.
The average cost of chimney sweepingHiring a professional chimney sweep will generally cost you between $100 and $300, with deep discounts at the low end of that range, and conditions requiring increased labor at the high end.
Dedicated DIYers can find chimney sweeping brushes online for as low as $20 if you're willing to put in the time, research, and labor. This route comes with risks, of course, particularly if working from the roof. Do it yourself and you'd also be missing out on the trained eye of a professional.
When you purchase a chimney sweeping service, after all, you're also in effect paying for the technician's experience and expertise. Additionally, chimney sweep professionals, because they sweep several chimneys a day, tend to invest in state-of-the-art, industry-grade equipment both for its effectiveness and efficiency.
Factors that increase costThough most companies have a standard price they charge for run-of-the-mill chimney sweep jobs, surcharges are often necessary for conditions that will render the job more labor-intensive or risky. Some examples:
Finding a companyPricing for a chimney sweep service will vary from company to company, as will the quality of work performed. Some questions you may consider asking in order to arrive at an informed decision include the following:
Wanna dig deeper? Download our free tipsheet: 5 Questions to Ask Before Hiring a Chimney Cleaning Company.
Air ducts can get pretty dirty. Disgusting even, as the below photo shows. When your home's air ducts look like this, a run-of-the-mill air duct cleaning job isn't going to cut it.
Why? Most basic-level air duct cleaning services feature high-pressured air as the mover of debris. But when said debris is abundant or "clingy" (e.g. drywall dust, pet fur), a more aggressive method is called for.
Cleaning the branch lines
The photo above was taken by one of our technicians in the branch line of a Minneapolis home, built in 2001, whose ducts had never been cleaned. As you can see, a lot of the debris is clinging to the walls of the duct, and the buildup is extensive. If this duct were to be cleaned with mere air pressure, a good deal of the debris would be pushed down the branch line into the main trunk for the vacuum to gobble up. But an unacceptable amount would be left behind, still clinging to the duct walls.
During the Ultimate Duct Cleaning, the first step of the process is for the technician to slip a tool called the Viper Microline down the branch line. Its single flexible-plastic tentacle is ideal for the snug confines of a branch line. When this tool is engaged, it thrashes quickly and vigorously every which way inside the duct, dislodging debris from the duct walls and sending it airborne. The tool moves slowly down the vent and through the duct, with its forward-blowing air nozzle blasting the debris in front of it as it moves, pushing it toward the trunk lines. The technician will take the Microline to each branch-line vent, pushing the accumulative mass of debris into the trunk lines before moving to clean those.
It is this physical contact of the tool with every inch of the duct wall that makes this level of cleaning so effective. Even stubbornly clinging dust stands no chance against the physical force of the Microline, as shown above.
Cleaning the trunk lines
Once the branch lines have been whipped, the technician moves to the main trunk lines to clean the debris accumulated from above. Because these ducts are much larger, the tool of choice here is the Viper Clean Sweep. This tool features six 16-inch long flexible-plastic tentacles, ideal for the roominess of main trunk lines.
With an industrial vacuum in place at an access point created just before the furnace in the main return line, the technician inserts the tool—it requires only a 1-inch access point--at the other end. From there the action is similar to that of the Microline but on a larger scale. As the multiple tentacles whip aggressively to and fro inside the duct, debris is dislodged and rendered airborne. The forward-blowing air nozzles send airborne debris toward the vacuum, and debris that isn't airborne is pushed forward by the thrashing of the tentacles. Either way, the collective fate of the debris is to be whooshed down the vacuum at the end of the line. The process is then repeated in the main supply line.
No top-of-the-line air duct cleaning would be complete without cleaning the furnace—the heart of the HVAC system. Since most homes with dirty ducts also have dirty furnaces, and since a dirty furnace will cause dirty air to move into the ducts, it makes sense to clean them both at once.
Letting the tool speak for itself . . .
No number of action words strung together in a sentence can convey the effectiveness of a tool better than a video of it in action:
We humans love our furry companions. And for some of us, let's face it, our perception of their cuteness directly correlates with their level of fluffiness (with exceptions, of course). Alas, our heating and cooling systems do not find their fluffiness so adorable. The monstrosity below was encountered by one of our technicians at a home in Plymouth, MN, when he created an access hole in their main return duct. At the risk of stating the obvious, the homeowners had a large dog, and it had been many years since their ducts had been cleaned.
Pet fur inside the air ducts
Those of us with pets know how ubiquitous their fur is—it's everywhere! As your pet moves around the home, loose hair becomes airborne and comes to rest on the carpet, on furniture, in your food(!), and in the vents. Since animal fur strands are generally much larger than run-of-the-mill household dust, they get hung up much more easily than smaller particles. Once hung up inside the ducts, they become a magnet for more fur and for other debris, creating mats of fur and dirt like the one pictured above.
Pet fur also builds up much more quickly inside the ducts. Whereas typical household dust takes years to build up to an extent that it needs to be removed, animal fur, because of its size and the sheer volume of it, reaches critical mass sooner. Consequently, while people without pets can get by on a standard or "maintenance-level" air duct cleaning every two years, as recommended, those with pets may wish to have the higher level of service performed as their "maintenance" duct cleaning.
Pet fur inside the furnace
Once pet fur is inside the vents, it moves through the ducts and, under normal circumstances, will be stopped from entering your furnace by the air filter. There on the filter it builds up and, unless the filter is changed regularly, it will become clogged with fur. With some frequency, our technicians have seen filters become so clogged that air cannot move through them, and the filter then bends and can even potentially be sucked into the furnace (and on at least one occasion, ripped apart by the blower wheel!).
Once the filter is clogged to this extent and bent, it is of course no longer functioning as a filter of any kind. At this point filter bypass comes into play, where debris simply goes right around the filter into the furnace. (Filter bypass can also occur when an air filter is ill-fitting, incorrectly installed, or extremely low-quality, such as cheap fiberglass, for example.)
The last place you want pet fur: the evaporator coil
It's inside the furnace and its various components that pet fur becomes extremely problematic, settling into the individual parts, clogging them up and reducing air flow. Since the entire heating and cooling system relies on good air flow to function optimally, efficiency can be greatly reduced when air flow is compromised by fluffy-furry debris.
The evaporator coil (A coil) is particularly susceptible to buildup, since all the air that circulates through your HVAC system passes through it. Both the furnace and the air conditioner will lose efficiency, work harder, and be subject to break-downs when air flow through the evaporator coil is compromised. The close-up above shows a mat of pet fur choking off air flow on the delicate fins of the coil. Because of the sheer size and "magnetic" quality of animal fur, if it manages to bypass the filter and reach the evaporator coil, it has the potential to disrupt the entire system
Above is what the evaporator coil should look like without its fur coat, the tiny holes free and clear of debris, allowing for easy movement of air and for the transfer of heat. If the coil above had a face, it'd surely have a smile on it.
Cleaning fur from the HVAC system
Considering the potential ravages of animal fur on the heating and cooling system, and that preventive maintenance is always a better (and less costly) option than repair, homeowners with pets should consider opting for the highest level of air duct cleaning service, including a furnace cleaning. Thereafter they should opt for at least the mid-level service as a maintenance cleaning. Why? Because for most companies, the top-tier service would include use of a tentacled air whip or brush used on the main trunk and the branch lines. The physical contact of the tool against the walls of the ducts—as opposed to the mere blowing that air pressure would provide—would aid in loosening any pet fur clinging to them.
A thorough furnace cleaning would then remove from the inner components of the furnace any fur that made it past the filter—hopefully before it becomes too abundant and reaches the evaporator coil.
So as a savvy homeowner and a diligent pet owner, in addition to frequently vacuuming your carpet to remove pet hair from all the places you can see it, consider having your air ducts cleaned frequently to remove it from all the places you can't
.Wanna dig deeper? Download our free tipsheet: 10 Questions to Ask Before Hiring an Air Duct Cleaning Company.
Many thanks to our technicians Ben S and Roy S for lending their expertise to this article.
Commercial exhaust systems serve to vent odors, moisture, and smoke from indoor spaces such as locker rooms, commercial kitchens, and bathrooms to the outdoors by way of a fan—similar to the way a home's kitchen or bathroom exhaust functions but on a much larger scale. These systems are continuously pulling bad air (dirtied with foul odors, moisture, smoke, cooking smells and oils, etc) from a large and crowded space. For this reason they tend to become quite dirty with filth and grime. When this product of exhaust builds up too much inside the ducts, proper venting to the outside is restricted, resulting in odors and moisture lingering in the occupied space. This has the effect of making the room in question "stuffy" and malodorous, and generally exhibiting poor air quality and circulation.
The above set of before and after images was taken inside a stretch of flexible ductwork belonging to the exhaust system of a municipal community center's locker room. The building itself was constructed in 1998, and the exhaust system had never been cleaned. The resulting accumulation of filth and fluff is visibly evident.
Because the area of the room being exhausted (in this case a locker room) is heavy with moisture and warmth from frequently running water, hot showers, hand and hair dryers, etc, the debris exhausted tends to stick quite readily to other particles and to the venting itself, causing a cumulative, clumpy buildup that's as stubborn as it is unsightly.
The flex duct above was cleaned using the Viper Clean Sweep System, a multi-tentacled whip attached to an air hose. When engaged, the plastic tentacles thrash vigorously to and fro, loosening debris from every crevice for the vacuum to swallow up.
Once the length of flexible duct leading from the locker room had been air whipped, it was time to tackle a larger run of rectangular metal ductwork that followed from it. Because this duct was large enough to accommodate a person, the crawl-through method was used to clean it. During this process, the technician dons personal protective equipment (PPE) and crawls through the duct on his hands and knees, armed with an industrial vacuum with brush attachments, physically brushing the debris from the walls of the ducts and into the vacuum.
In this case, the technician moved through the length of the duct until reaching a large turbine fan, which was also caked with locker-room grime.
To clean the fan, the technician water-blasts it with a pressure washer, washing decades of dust and debris from the surface of the fan and blades. The water is cleaned up with a wet vacuum, and the fan blades and other components are wiped down with a dry cloth. Once one side of the fan is clean, the technician exits the duct through an access hole created earlier, then enters the duct on the other side to finish cleaning the other side of the fan.
Having thoroughly cleaned the fan, the technician then turns his attention to the 15-foot section of rectangular duct remaining before the outside grille. This section is also cleaned with the crawl-through method, with the debris manually brushed off the walls of the ducts going straight into the industrial vacuum, which sits below. (The technician enters the duct with enough hose to accommodate the length of the duct.)
The final step is to clean the outside grille that sits like a window on the exterior of the building. The same manner of dust and grime found inside the flex duct and rectangular duct clogs the tiny holes on the screen of the exterior grille. To clean this, from the inside, the tech washes it thoroughly with a pressure-washer. While most of the excess water from this process runs down the side of the building, whatever is left inside the duct is sucked up with a wet-vac.
The ultimate result of this days-long job is a community center whose occupied spaces boast a visibly cleaner venting system, improved indoor air quality, fewer odors, and a generally improved atmosphere.
Wanna learn more about the process of commercial air duct cleaning, the various components cleaned, and the tools employed?
View Commercial Duct Cleaning Page
Many thanks to our commercial project manager Ben S for contributing photos and wisdom for this article.
The heat exchanger pictured is definitely not representative of our typical job. Furnace cleaning, when performed regularly, is relatively uneventful, as the technicians use high-pressured air triggers to clean various components inside the furnace, and check key areas for proper function. The goal is to rid the furnace and its inner workings of dust and debris that hinder efficiency and that increase the number of contaminants polluting indoor air. As in any frequent task, however, sometimes unusual or exemplary situations present themselves
This month a homeowner in St Paul contacted us and scheduled a furnace flue cleaning as well as a furnace cleaning. His gas furnace, manufactured in the 1950s, was less efficient than it had been (not surprisingly, some would say). More importantly, he felt it was not drafting properly. He was getting what he called "funny smells" in the house, and the carbon monoxide detectors were going off. The customer attributed this to a clogged furnace flue, which is certainly not an unlikely cause. The furnace flue serves to vent harmful gases produced during combustion to the outside, so if it is clogged or otherwise hindered, it stands to reason that a primary indicator would be the CO detector registering concerning levels of carbon monoxide.
After listening to the homeowner's concerns about the furnace not drafting properly, the technician proceeded to clean the flue, expecting to find it clogged, perhaps with animal nesting or other debris. Though quite dirty, however, it was not so dirty that one would have expected air flow to be greatly hindered or draft compromised.
The problem became apparent, however, when the technician was able to see, by way of the access created for the flue cleaning, down into the heat exchanger. It was completely clogged and black with soot, to an extent he'd never seen before. It was clear to the technician that a through cleaning was urgently needed to unclog it and restore it to working order, if possible.
A disclaimer would be in order at this point. The average lifespan of a furnace is about 20 years, and the furnace in question was significantly older than that. The customer insisted, however, that it was otherwise working properly and he simply did not have the funds to replace it. Wanting to accommodate the customer's financial situation, the technician agreed to proceed with the disassembly and cleaning of the heat exchanger, with a thorough explanation of what he was doing and the risk involved, and an assurance from the customer that if the symptoms persisted after the cleaning he would consult a repair company.
An interesting aside: furnaces of this age rely on natural draft to exhaust gases and are not equipped with a draft inducer. This component is essentially a fan, found in modern furnaces, whose purpose is to create draft and move the products of combustion from the furnace up and out the flue. A furnace equipped with a draft inducer likely would shut down rather than becoming as clogged as this one had, in accordance with its sequence of operation.
The technician began the job by removing 17 nuts and bolts from the panel just to gain access to the heat exchanger. As soon as the panel was removed, it was clear that the gasket surrounding it was completely deteriorated and needed to be replaced. The customer purchased a new one while the technician performed the cleaning.
It is unusual that a technician would need to go to such lengths to access a heat exchanger. Typically the heat exchanger is readily accessible, or requires only minimal disassembly in order to access it for cleaning. Moreover, many technicians would likely have passed on this job once observing the amount of buildup needing to be cleaned and the relatively laborious process of accessing the heat exchanger. Likely the customer would have been counseled to simply replace the furnace. However, a combination of a genuine wish to help a homeowner in a tough financial situation and the desire to successfully tackle a challenging and uncommon task inspired our technician to complete the cleaning.
Once the heat exchanger was accessible, the cleaning was carried out using a powerful industrial vacuum and various attachments, specifically a 3-inch round brush head. Because the heat exchanger and its associated tubes were so large, it was easy to fit the vacuum and its attachments down each tube, which made this aspect of the cleaning relatively easy, taking only about 20 minutes.
On completion, the customer replaced the gasket with the one he had purchased, and the heat exchanger panel was reinstalled.
The heat exchanger after the cleaning was not necessarily a thing of beauty, but it certainly was in a much improved condition to carry out its function of heat transfer. In the end, the tech was wiser, the customer was well-informed and happy, and he also was not out thousands of dollars for the purchase of a new furnace—at least not today.
Wanna dig deeper? Download our free tipsheet: 5 Questions to Ask Before Hiring a Furnace Cleaning Company.
Many thanks to our technicians Ben S and Roy S for lending their expertise to this article.
As a furnace cleaning company, we sometimes get calls for issues that would be more appropriately referred to a furnace repair company. Sometimes customers with furnace troubles attempt the process of elimination to reach a diagnosis, eliminating the least-expensive potential fix first (cleaning). Though there is some minor overlap between cleaning and repair, if your furnace is not working, your first call should be to a repair company.
With that said, furnace cleaning can help minimize the need for furnace repair, and on occasion, the recommended repair is simply to clean a specific malfunctioning (read: dirty) part. Additionally, furnace cleaning technicians are typically equipped to replace minor parts, such as flame sensors and hot surface igniters
Your Furnace's Sequence of Operation
To understand the relationship between furnace cleaning and the unit's smooth functioning, it helps to understand a furnace's "firing order," formally known as its sequence of operation. This is the series of steps a gas furnace runs through before generating heat. In a nutshell, once heat is summoned by the thermostat, the draft inducer motor begins whirring. The air pressure switch then monitors the air flow being generated by the inducer to make sure it is sufficient, and if it approves, a connection is made between the inducer and the hot surface igniter. The igniter then glows and the gas valve opens, creating a flame. The flame sensor, for its part, then asks, is there a flame? If the answer is yes, the process remains uninterrupted and heat is generated. If the answer is no, the system will shut down, in order to prevent the release of raw gas into the atmosphere with no flame to consume it. This process continues until the thermostat reaches the desired temperature.
Any interruption to this sequence of operation will effectively halt the furnace, and there are plenty of factors that can contribute to an interruption. If the draft inducer is compromised, for example, the pressure switch will not communicate to the igniter that everything is A-okay, and the igniter will not spark. Dirt and debris can play a major role in these interruptions. A furnace flue clogged with debris would prevent the inducer from creating enough draft to close the pressure switch, stopping the process before it even gets started. A worn or dirty flame sensor incapable of detecting a flame would result in the gas valve shutting off. You get the idea.
The Primary Goal of Furnace Cleaning
Despite furnace cleaning sometimes resolving what would seem to be repair issues, its chief aim is maintenance—helping to keep the system in working order by improving air flow through the removal of system-clogging debris. As explained above, a single dirty component can stop the heating process in its tracks. Maintaining system cleanliness will minimize disruptions to your home's heating.
An additional aim of furnace cleaning, and HVAC system cleaning in general, is the improvement of indoor air quality: by removing debris and contaminants from your furnace and other system components, you reduce the number of pollutants circulating throughout the system only to be expelled into your living space. That same debris that clogs up HVAC system parts and hinders air flow doesn't do your lungs any favors either.
Overlap Between Cleaning and Repair
If we refer back to our sequence of operation and the issues that can disrupt it, we have to consider that sometimes the problem is as simple as a single faulty part. Though the lifespan of a furnace is roughly 15-20 years, the lifespan of some individual parts is much shorter. The igniter and flame sensor, for example, have lifespans of only about 5-7 years, so it stands to reason you'll need to replace these before you replace the furnace itself. Because these parts are fairly easy to install and small enough to carry a sufficient stock, many furnace cleaning technicians will replace these, with the customer's approval, if they observe much wear on the part. The replacement of these components, in addition to capacitors and contactors, are about the extent to which furnace cleaning technicians will engage in parts replacement.
One of the biggest (and most dangerous) cleaning-related repair issues is when the furnace shuts down due to a clogged furnace flue. The flue, of course, is the channel or pipe through which harmful gases produced by the combustion of your furnace are exhausted to the outside. If the flue becomes clogged with animal nests, leaves, or other debris, harmful carbon monoxide can back up into your living space and put your family at risk. Furnace flues without caps are particularly susceptible to this hazard. Our technicians are frequently called to the homes of customers whose furnaces have been red-tagged and shut down by a repair company due to a blocked flue.
A surprisingly common contributor to furnace overheating and subsequent shut-down is a clogged air filter. If the filter is choked with dirt, air flow from the return duct into the furnace is restricted and can cause the high-limit switch to detect too much warmth and shut off the burners. A blanket of dust over the evaporator coil can have a similar effect, restricting air flow from the heat exchanger to the supply duct and causing a backdraft. Because the entirety of the HVAC system is dependent upon proper air flow, any hindrance to this flow in the form of dirt or debris can wreak havoc and lead to repair issues.
When to Call it When
If your furnace is not working, or not working well, your first call should be to a repair company. It may end up that the diagnosis involves the evaporator coil needing to be cleaned, or that the furnace flue is dangerously clogged, both of which you'd likely be referred to an HVAC cleaning company for. However, the diagnosis should come from a licensed HVAC repair technician. Sometimes similar symptoms can have different causes, so to rule out any other issues, a proper evaluation should be performed.
If you are looking for a cleaning of your furnace or furnace flue as part of routine maintenance on your system, or if you are looking to improve your indoor air quality by minimizing pollutants present within, call a furnace cleaning company. During the course of their service they'll make mention of anything they see amiss and refer you to a repair company if appropriate.
Wanna dig deeper? Download our free tipsheet: 5 Questions to Ask Before Hiring a Furnace Cleaning Company.
Many thanks to our technician Roy S for lending his expertise to this article.
Or rather, some stories. Everybody loves the before and after photos some companies offer after an air duct cleaning job. Customers like to see the results of the service and the accompanying assurance that their money was well spent, not to mention the visible affirmation that they'll be breathing cleaner indoor air. HVAC cleaning companies enjoy showcasing their work, and before and after photos provide explicit testimony of the benefits of the service. Below are a few examples, with context and caveats
The images above are from a 70-year-old home in St. Paul whose ducts had never been cleaned. The duct is a standard sheet-metal return, fairly easily cleaned with a multi-tentacled air whip such as the Viper Clean Sweep, our technicians' tool of choice.
The photos were taken (as all of ours are) with the technician's cell phone—not, as many customers assume, with a scope. The reason we opt for cell-phone photos over those of borescopes is due mainly to resolution, and ease: a cell-phone photo has a much higher resolution than that of a scope, providing a high-quality and detailed image. Cell-phone photos can also be shared much more easily, quickly sent from the technician's phone to the customer's e-mail. Finally, a visual representation of the condition of the ducts can be had more easily from an access point or vent than from deep within the duct (which would require the use of a scope), with the latter providing no obvious advantage.
The images above were taken inside a Minneapolis home built in the 1960s in which the trusses (the cavity between the main-level floor and the basement ceiling) were used for return air. This building practice was relatively commonplace until recently. These kinds of duct spaces can get quite dirty, due to the porousness of wood and the tendency of dust particles to coagulate within that space. That is to say, dust particles stick more easily to wood than, for example, to metal, and once one particle sticks, subsequent particles stick more easily, resulting in quicker and more abundant buildup than inside a metal duct. This cavity was also cleaned with the Viper Clean Sweep.
In cases of newly constructed homes (above), the ducts are often dusty with drywall particles, which are ubiquitous and stubborn. At first glance this debris may not appear as voluminous as that in some of the other photos. However, because drywall dust tends to collect so densely, it can be considered equivalent to twice its amount in run-of-the-mill household dust. Drywall dust is easily disturbed, and because its particles are so small and lightweight, once rendered airborne, they create a nuisance everywhere they settle—within HVAC system components, on your furniture, in your lungs.
You may notice in the image that a few larger (relatively) pieces have been left behind inside the ducts. These are heavier bits of concrete or rubble that, because of their weight, cannot be removed by duct cleaning tools. This is of little consequence—these are too heavy to become airborne and thus are not going to compromise indoor air quality.
Flexible poly return ducts (above) are commonly found in townhomes in Minnesota. That pictured is from a townhome built in the early 2000s. Because this particular duct was located in the main living space, the dirt within was an accumulation of debris generated over several years, from the kitchen, dining, and living areas. The after photo demonstrates the subtle power of the Viper Microline, a single-tentacled air whip perfect for smaller cavities. Because it is not as forceful as multi-tentacled air whips (or brushes), it does not harm flex lines, but its gentle and swift thrashing loosens debris from every nook and cranny.
Because debris from wood-floor sanding is easily airborne, it often finds its way into a home's air ducts (above). Like drywall dust, this debris tends to cling to the walls of the ducts and its removal requires a more advanced cleaning than that which simple air-pressure provides, such as a rotary brush or tentacled air whip. Our technicians prefer the latter, especially in rectangular ducts (as rotary brushes are circular).
A final word on before and after photos: those that you see online, for obvious reasons, tend to place toward the end of the best-to-worst spectrum, the above included. Though those included here are fairly typical jobs that our techs see regularly, there are plenty of others that are not so remarkable or exemplary, especially in homes whose ducts are cleaned regularly. The salient point here is that no matter what your ducts looked like before cleaning, the top-level cleaning, utilizing an advanced agitation method as opposed to simple air pressure, will get them picture-perfect after.
Wanna dig deeper? Download our free tipsheet: 10 Questions to Ask Before Hiring an Air Duct Cleaning Company.
Many thanks to our technicians Ben S and Roy S for providing photos and lending their expertise to this article.
It's a fair question, as the two are very similar, and in one case (the fireplace flue), they're the same. The two terms are often used interchangeably, even by industry insiders, as there is much overlap. But there are distinct differences between the two as well. Let's break it down
What's the difference between a chimney and a flue?
A flue is the channel, pipe, or tube through which gases and smoke travel from a source of combustion (fireplace, furnace, boiler) to the outside environment. It is usually a vertical channel, but in some cases, as in fan-powered PVC power vents on newer, high-efficiency appliances, the flue can be horizontal. But here we are speaking of the traditional draft-style flue. That is, those that rely on natural draft—the upward movement of air as a result of differences in temperature and pressure—to safely vent the products of combustion from the home.
A chimney is, on the other hand, in its simplest definition, the housing that encases the flue. It is usually made of masonry, brick, or stone. Its exterior, extending upward beyond the roof line, is generally what we think of when we consider chimneys. It's worth noting that a chimney that does not have a flue inside it or a liner is basically serving as the flue itself.
How do chimney sweeping and flue cleaning differ?
Bearing in mind that a flue is the path through which the byproducts of combustion vent to the outside, a "fireplace flue" is the same thing as what laypeople think of as a chimney—that structure which Santa will hopefully climb down later this month, if we're lucky. So, a fireplace flue cleaning and a chimney sweeping refer to the same process. During the service, the technician generally uses a stiff-bristled brush or other chimney cleaning system to brush the inside of the flue to remove creosote buildup from its walls.
A utility flue cleaning—as opposed to a fireplace flue cleaning or chimney sweeping—would be focused on the vertical flue associated with the furnace, boiler, or water heater. Because these appliances do not generate creosote (which is a byproduct of burning wood), their flues typically do not get as dirty as fireplace flues, and the buildup they do accumulate is not as hard or caked-on, so to speak.
For that reason, the tool of choice on a flue cleaning (though every technician is different) would be a tentacled air whip. Because these are powered pneumatically by air pressure rather than manually, they are highly efficient and are quite effective at removing the scale-and-sediment buildup prevalent within utility flues, as opposed to creosote, which requires more aggressive methods.
How are they similar?
The two processes are similar in that they are both designed to remove buildup and blockages from the inside of the flue to allow free and safe passage for the gases and smoke produced by combustion. In the case of blockage removal, the process is virtually identical, as the debris that blocks both fireplace flues and utility flues is almost always of the same origin: animal nesting. To remove it, the technician will break up the nest using whatever brush or whip will work most effectively, simultaneously sucking up the debris with a vacuum attached below. He'll then complete the job by thoroughly brushing (or whipping) the sides of the flue to remove any remaining or stuck-on debris.
Finally, no body of information remotely associated with flue or chimney health would be complete without reference to the importance of chimney caps. They're vital, and without them, your roof has a gaping hole, inviting all kinds of weather damage and critter entry. It's the single easiest and most cost-effective way to maintain your chimney—or flue!
Wanna dig deeper? Our flue cleaning service page has a detailed description of the process involved and tools used, as well as links for further reading.