Air duct cleaning is generally available in various tiers or levels of service, ranging from a simple cleaning to comprehensive and something in between—“good, better, and best,” if you will. With a diversity of tools and techniques available, choosing the one that's right for you can be confusing. Here we'll break down the options available and which level of service is most appropriate for a given situation.

Standard Air Duct Cleaning

A standard air duct cleaning is a rudimentary cleaning—the “minimalist” approach. All air duct cleanings will consist of at least a vacuum and air pressure. The vacuum is inserted into the main trunk lines in order to create negative pressure in the ductwork system. Standard practice would then be to use air wands to blow high-pressured air into each of the vents in the branch lines to force debris toward the vacuum. Sometimes this process is helped along by air snakes or skipper balls in the main trunk. These tools consist of a metal ball at the end of an air hose that is fed toward the end of the line. Once engaged, air is forced out of tiny holes in the ball, blasting debris toward the vacuum as the tool is pulled toward the technician.

A standard cleaning might be an appropriate choice if your home’s ducts are well-maintained and cleaned regularly, as it removes small amounts of superficial debris; it is not effective for large amounts of debris or stubborn debris that clings to the sides of the ducts, like, for example, pet dander or drywall dust. It is important to remember that the only physical contact of the ductwork in the standard duct cleaning process is the sliding of the skipper ball across the bottom of the main trunks. The sides, corners, and top of the mains and the entirety of the branch lines remain untouched, but for air pressure.

Advanced Air Duct Cleaning

This mid-level cleaning is a more appropriate starting point in most cases, especially if you’re not sure how long it’s been since your home’s air ducts have been cleaned. It includes the vacuum and air pressure of the traditional cleaning but adds an additional measure in the form of an agitator—a tool designed to physically loosen debris and move it toward the vacuum, used in the main supply and the main return. Perhaps the most familiar agitation tool is the rotary brush--a round brush, attached to a cable, that spins inside the duct and brushes the top, bottom, and sides. Another popular agitator—and arguably more effective—is a multi-tentacled air whip (some brand names include the Octopus Predator or the Viper Clean Sweep). When engaged, the tool’s tentacles thrash vigorously every which way inside the ducts to knock debris loose and send it toward the vacuum.

Though the agitation tool renders the advanced a more thorough cleaning than the basic in terms of the trunk lines, the branch lines are typically limited to cleaning with high-pressured air, as they are in the basic cleaning. This advanced level of service is appropriate when most of the debris in the ductwork is located in the main supply and the main return lines. It should be noted that for some duct cleaning companies, this is their highest level of service.

Ultimate Air Duct Cleaning

Typically each level of service builds on the previous. So just as the advanced includes the process of the standard cleaning and adds the agitation tool in the main trunks, the ultimate or top-level cleaning includes all of the features of the advanced, with the addition of the use of an agitator in not only the main trunk lines but the branch lines (or vents) as well. Sometimes this tool is a smaller version of the agitator used in the mains (e.g. a Viper Microline), the size of which obviates the need to remove any register covers, and sometimes the same agitator is used as is in the main trunks, requiring removal of all register covers.

Because in this process an agitator is physically contacting all surface areas of the ductwork, it is the most thorough process available. This level of cleaning is appropriate on taking new ownership of a home, if pets are present, after new construction or remodeling has occurred, or if the homeowner just wants peace of mind that the ducts are as clean as they can be. Typically companies add on extras at this level of service, such as a furnace cleaning, sanitizer, before and after photos, etc.

When in doubt, have the technician assess

With all that said, if you’re not sure which level of duct cleaning your home needs, and you don’t want to spend more than you have to, most companies have a process whereby the technician can assess the condition of your ducts and make a recommendation before work begins. One of the considerations he’ll take into account is how many stories the home is; that is, how many stories up do the trunk lines extend before they feed into the branch lines and reach each of the rooms. If this is a great distance, you may want to use more than high-pressured air to clean the branch lines.

Another fairly reliable (and easy) method for determining how dirty your ducts are is to look inside the vents themselves. If there is a buildup of debris visible when you remove your register covers, it is a fairly safe assumption that the rest of your ducts have a similar buildup. A lack of buildup in the vents would suggest that the majority of debris is located in the main trunks, and the lower or mid-tier cleaning may suffice.

An experienced technician will be eager to share his knowledge and help you understand the reasons for his recommendation. Ultimately the choice is yours, but an understanding of the different processes involved, as well as knowledge of the setup and history of your home's HVAC system, will help to appropriately set expectations.  

Wanna dig deeper? Download our free tipsheet: 10 Questions to Ask Before Hiring an Air Duct Cleaning Company. 
​
Download Tipsheet
 
 Many thanks to our technicians Roy S and Ben S for lending their expertise to this article. 

HVAC cleaning technicians wear many hats besides those of mere chimney sweeps and air duct cleaners. They're also adept cell-phone retrievers (air ducts), daring rooftop climbers (dryer vents, chimneys), and often, animal control. Because of the warmth generated by various HVAC components, animals frequently seek shelter within, often with a not-so-favorable outcome for either the animal or the system involved. Sensitive readers may want to skip this article (but before you go, rest assured the service involving the squirrel babies below had a happy outcome).

Case Study #1: Baby Squirrels Around the Furnace Flue

The image above was taken by one of our technicians who was called to install a chimney cap on a furnace flue. When he reached the top of the ladder and was about to peer down, a female squirrel came bounding out of the chimney, startling him. When he gazed down into the chimney, he saw the reason for her frenzy: three tiny furless bundles, huddled together next to the warmth of the furnace flue. 

Squirrels have a talent for building platforms made out of sticks and other debris, inside chimneys. In this house, a new flue had been fashioned to run up through the middle of an old, unused chimney from an octopus furnace. The squirrel mother had chosen prime real estate for her brood: within the chimney but outside of the main flue, close enough to the heat source to enjoy its warmth, but not so close that it would ignite. 

The sight of the babies melted our technician's heart, as well as that of the homeowner. Animal control was called, and the nest and squirrels were transported safely to another location. The old flue and the new flue were covered and capped to prevent further animal intrusion.


Case Study #2: Duck (dead) in the Fireplace Flue

Sometimes the first (unfortunate) indication that a homeowner has an animal stuck in their fireplace flue is a rancid smell emanating from the firebox, which was the case here. After arriving at the property and inspecting the fireplace, the technician diagnosed the problem as a dead animal on the smoke shelf. Located in the chimney throat, behind the damper, the smoke shelf can be a difficult area to access. Our technician donned rubber gloves and reached over the damper but could not reach the animal. He then used a powerful vacuum hose to lift it from the smoke shelf, at which point he was able to reach it and pull it out from behind the damper. Once the duck was removed, he ran the vacuum hose several time across the length of the smoke shelf to ensure no debris or feces remained behind. He then swept the rest of the chimney and finished it off on top with the installation of a chimney cap.

Case Study #3: Mother of All Squirrels' Nests in the Fireplace Flue

In this case, after a homeowner removed a squirrel from their fireplace, our technician was summoned to place a cap on the fireplace flue to prevent a recurrence. When our technician climbed to the rooftop and peered down into the chimney, he observed a dense collection of sticks and leaves completely obstructing the flue.  He informed the homeowners that had they lit a fire in their fireplace, they would have smoked their house out, which is to say that the nest obstruction would have prevented the smoke from exiting their house through the chimney, leaving it nowhere to go but inside the house.

To clear the obstruction, our technician aggressively pushed a chimney cleaning brush up through the nest and pulled down, repeating a few times until the debris fell in a large pile into the firebox, from where it was removed. He then swept the rest of the flue with wire-bristled brushes. The firebox and smokeshelf were thoroughly vacuumed to remove any remaining debris. As is customary, the final step in any chimney cleaning process--especially if animal intrusion is involved--is to install a chimney cap to prevent re-entry. In this case, the homeowner elected to have their furnace flue capped as well, since a clogged furnace flue can result in carbon monoxide backing up into the home. 


Every Flue Needs a Cap!

The common thread in all of these cases, of course, is an uncapped flue or uncovered chimney. Chimney caps and covers are sold, or can be custom-made, in any shape or size and a huge variety of materials, such that no flue can excusably be left uncovered. A chimney without a cap is essentially a hole in your roof. It is a lot less expensive and much less trouble to simply cover a flue than to wrestle with the fallout from a deceased and decaying animal, an obstruction in the form of a nest, or the risk of fumes backing up into the home because of a clogged utility flue. 

Ready to cover that hole in your roof by installing a chimney cap?

Many thanks to our technicians Ben S and Roy S for lending their expertise and contributing photos for this article.

That wire screen over your rooftop dryer vent may well be keeping out critters, but it's also creating an extreme fire hazard. It's not supposed to be there.













​

What is the regulation regarding dryer vent covers?

Though exceedingly common, for reasons we'll explore later, it is against International Regulation Code, and generally an unsafe practice, to place or keep any kind of screen over a dryer exhaust vent. The specific code, M1502.3, regarding dryer duct termination, is worth quoting in full:

Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer's installation instructions. If the manufacturer's instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.

Why is it dangerous to keep a screen over a dryer vent exhaust?

Though screening is commonplace over chimneys, furnace flues, bathroom exhausts, etc., for the main purpose of keeping animals out, it is ill-advised over a dryer vent exhaust, because in addition to exhausting moisture and heat, dryer vents also exhaust small bits of lint. Moisture exhausted acts as a glue that adheres the lint to the screen, and, over time, the holes in the screen become completely choked with lint, cutting off airflow and creating further blockages down the vent line. This buildup of lint, which is highly combustible, creates an extreme fire hazard. The restricted air flow also impairs the efficient function of your dryer and can cause the thermal fuse (a device specifically designed to trigger in the case of a high-heat event) to blow out, leaving you without a dryer until it can be replaced.

If I remove the screen from my dryer vent, what keeps animals from entering?

Your dryer vent, behind the screen, should have a louvered flap that swings open when the airflow from the dryer opens it and then falls back into the closed position when the airflow ceases. If the vent does not have this feature, it should be replaced. You'll want to inspect the cover every so often to make sure it's intact and none of the louvers are missing, which might present a welcome invitation to a furry critter seeking warmth.

Why the heck do dryer vent exhausts even have screens on them?

It seems the default is that rooftop vents, whether bathroom or dryer, come with screens over them and are installed as is. Why are they not removed in the case of dryer vents? I posed this question to several roofing companies in the Twin Cities, all of whom were forthcoming and generous. One replied that they do not remove them so as not to expose the homeowner to the possibility of animal entry. Another explained that they are kept in place for reasons of liability, presumably referring back to the animal-entry scenario, as well as the fact that the screen is installed by the manufacturer. A third explained that indeed they do remove the screen when the vent cover they're installing is designated for a dryer, and they mark them for this purpose, so as not to neglect that final step once the job is complete.

What's the consensus?

Remove it. Regardless of how the screen got there, it should not remain. If you cannot remove it yourself, your dryer vent cleaning company will (or should) do so during the course of the cleaning. Unfortunately, the screen is often not detected until the dryer's performance begins to suffer and the homeowner calls a dryer vent cleaning or repair company seeking explanation.

Coincidentally, one of the roofers I spoke to said that he had just been on his own roof the night before to clean out his dryer vent. He noticed the screen and removed the pesky thing himself.  

Wanna dig deeper? Download our free tipsheet: 5 Questions to Ask Before Hiring a Dryer Vent Cleaning Company.

Download Tipsheet

Many thanks to our technician Ben S for lending his expertise to this article, as well as our friendly neighborhood roofing companies. 

​One of the easiest ways to keep your central air conditioner running smoothly is to keep its various parts clean. The condenser unit (outside) and the evaporator coil (inside) work harmoniously to move warm air from your home outside and produce cool air within. If one or both of them are dirty or clogged, air flow is diminished, efficiency is reduced, and you and your wallet suffer. Keeping these and other parts—including the air filter and drain line--clean and clear of debris will go a long way toward maintaining the overall system’s smooth function during the time you need it most.

​​The Condenser

The condenser is the part of your air conditioner that is located outside your home. Its job is to circulate coolant through the A-coil and expel the heat it absorbs outside. Over time, the fins on the condenser unit become clogged with debris, including dirt, dead leaves, grass clippings, and various other plant matter that the fan manages to suck in. This debris makes it harder for the condenser to release heat and places a strain on its various components. When the fan draws air in through debris-clogged fins, the unit suffers from reduced efficiency and is more subject to breakdowns. Additionally, the debris hinders air flow and can cause the unit to not cool properly.


The A-Coil

The evaporator coil, or A-coil, is usually located above the furnace in the plenum. Its job is to absorb heat from the home’s indoor air and transfer it, via refrigerant, to the outside condenser for release. Though the evaporator coil does not play a role in heating your home, the air heated by your furnace in the winter months passes through it before entering the supply ducts. In fact, all of the air that moves through the HVAC system passes through this coil. More exposure to air flow, of course, means more exposure to dust and debris. Over time, dirt contained in the moving air collects on the surface of the coil, acting as an insulator and inhibiting heat absorption. A dirty evaporator coil inhibits not only cooling your home in the summer but heating it in the winter as well, because of diminished air flow. 

The Air Filter

The air filter (aka furnace filter or air conditioner filter) is usually located in the return duct, before the blower compartment. Though the common perception is that the main role of the air filter is to prevent dust from entering your living space, its primary purpose is to prevent dust from entering the fan compartment and dirtying the evaporator coil. Because the evaporator coil requires unhindered air flow to work its magic (heat absorption, if you missed it above), even the smallest amount of dirt will reduce efficiency. Equal in importance to maintaining your air filter is ensuring there are not any "filter bypass" issues, when an ill-fitting or improperly installed filter allows air to sneak around it and head straight for the fan and A-coil.

The Condensate Drain Line

The AC condensate drain line, usually made of PVC or rubber hose, drains excess moisture produced by the evaporator coil and transports it to a drain often located somewhere near the furnace or to a condensation pump. This line over time becomes plugged with dirt, algae, and mold. Water pooling around the furnace is often the first indication of a plugged drain line. Keeping your condensate drain line free of blockages is crucial to the proper functioning of your AC.

Hiring a Professional

DIY tutorials abound on how to clean each of these parts, and a determined homeowner with sufficient time and suitable tools would achieve some measure of success. However, the A-Coil, which is arguably the most important component to keep clean, is also the most difficult to clean (and sometimes inaccessible). Further, having your system professionally cleaned would allow the HVAC technician to check for proper air flow and look for filter bypass issues, check system components, and verify that refrigerant levels are where they should be, adding more if necessary.

Wanna learn more about the air conditioner cleaning service? 

Visit Air Conditioner Cleaning Page

Many thanks to our technician Roy S for lending his expertise to this article.