The above photo was taken at an apartment building in Chaska before the dryer vent was cleaned. It can be assumed that when lint is hanging off of the outside vent (and had to travel a good distance to get there) that there is a buildup of lint inside the vent line and cleaning is needed. Of course, a dirty dryer vent line will not always result in lint hanging from or stuck to the outside vent, so it should never be assumed that if lint is not visible on the outside, it is not present on the inside.
 
What is the difference between residential and commercial dryer vent cleaning? 

Typically, in a commercial setting—that is, in multi-unit dwellings--the dryer is located more toward the interior of the building and not as close to a wall, through which the vent will finally exhaust. This means that in most cases, the run is longer—sometimes 35 to 50 feet in length--than in a single-family home, and it also contains more twists and turns than those that vent in a straight shot through the wall to the outside. In many cases, dryers in multi-unit dwellings vent onto the roof. All of this means that the process for cleaning the vent line is more complex and the need more frequent than in a residential setting.

How are commercial dryer vents cleaned?

In apartment buildings and condominiums, it is rare that any dryer vent lines are shared; typically each unit has its own dryer and dryer vent line, which exhausts somewhere out the side or roof of the building. In some cases, the first and subsequent floors vent out the side of the building, and the top floor vents to the roof. In other cases all dryers vent to the roof.

Regardless, the process for cleaning them is similar. The technician positions himself where the dryer exhausts (using a lift to reach the higher floors). He inserts a cleaning tool attached to a high-pressured air line into the vent and feeds it down the vent line, as far as it goes, until it reaches the back of the machine itself. When the tool (a reverse-blowing spinning air ball") is engaged, it spins around and spits out air through tiny holes in the metal ball. As the technician slowly extracts the tool, the lint is blown out with it (quite forcefully; most technicians wear face masks). The technician repeats the process if necessary until he has confirmed good air flow from the vent.  Importantly, the technician will also remove any screening that is in place over the dryer vent, as this is a violation of code and additionally a fire hazard. 

How often should commercial dryer vents be cleaned?

Typically dryer vents in multi-unit dwellings such as apartments and condominiums should be cleaned yearly. Most properties of this nature have an ongoing yearly contract for service with an HVAC cleaning company.

Estimates can be provided for the cost to clean all vents in a building in a single service, and prices vary depending on how many units to be cleaned, how many stories in the building, how long the dryer vent lines run, and where the dryers exhaust. Obviously, the more units, the higher the total price (though the cost per unit tends to decline as the number of units increases). Higher floors would necessitate the rental of a lift, which would also contribute to the estimate total. 

Reputable commercial dryer vent cleaners are equipped and experienced to handle properties of all sizes and configurations, and yearly contracts establish consistency and predictability with the project, making planning easier on property management companies—and dryers safer and more efficient for tenants. 

Wanna dig deeper? Our commercial dryer vent cleaning page contains detailed descriptions, before and after photos, and videos of our commercial dryer vent cleaning processes.

View Commercial Dryer Vent Cleaning Page

Many thanks to our commercial project manager Ben S for lending his expertise to this article. ​

Identifying the source of attic mold

Since every mold problem is the result of a moisture problem, the first step in mold cleanup is identifying the origin of the moisture or water intrusion and remedying it completely. Leaky roofs can be caused by missing or damaged shingles, cracked or damaged rooftop vents, missing flashing, or a deteriorating chimney, among other things. Bypass (air leakage) around light fixtures, wires, or flues into the attic are another frequent cause of moisture; gaps or holes surrounding these provide passage for the warm, moist air from your home to travel upward into the attic, where it can condense and elevate relative moisture. Disconnected venting, particularly from clothes dryers or bathroom vents, allows hot and humid air that should be exhausted outside to be expelled into the open attic space, creating conditions extremely favorable to mold growth. Once the source of moisture has been identified and corrected, the remediation process can begin.

The attic mold remediation process (in a nutshell)

Before beginning remediation, the affected area is sealed off from the rest of the home with polyethylene sheathing and placed under negative pressure with the help of a negative-air machine. This practice prevents contamination of other areas of the home. Once this has been accomplished, the removal of mold from affected areas can begin. Insulation is discarded, and visible mold is removed from all surfaces. This can be accomplished with abrasive methods, such as dry-ice blasting or soda blasting, or with chemical methods such as MMR or RMR. Every surface is then contact-vacuumed with a HEPA-vacuum to remove mold spores. A fungicide is applied to every surface, to kill mold spores and prevent regrowth. Finally, every surface is again contact-vacuumed with a HEPA-filter vacuum, removing any remaining mold spores.

Encapsulating to inhibit future growth

Once all mold has been removed from surfaces, homeowners may choose to apply a product known as a mold encapsulant to protect non-porous surfaces from regrowth. Some products used for this purpose are Foster 40-51 or Fiberlock AfterShock. Encapsulants are applied in a manner similar to painting and work both to protect a cleaned surface and leave it less fertile to regrowth, as well as to seal in and render immobile smaller particles that could not be removed. 

An ounce of prevention . . .

Of course, preventing a problem is almost always easier and less expensive than remedying one, especially where homes are concerned. To pre-emptively guard against mold growth in your attic, ensure that your roof, chimney, and any associated flashing are well-maintained. Address any air leakages around recessed lights, wires, vents, or flues with caulk or other appropriate measures. Fortunately, DIY tutorials abound on this subject. You'll also want to ensure that none of your HVAC systems vent inside the attic. HVAC cleaning technicians regularly ensure proper air flow after cleaning a dryer or bathroom vent and consequently have saved lots of homeowners from potential damage in that regard.
Wanna learn more about mold testing, remediation, and inspection? Visit our mold servicespage.

Visit Mold Services Page

Thanks to our mold remediation specialist Zach C for lending his expertise to this article.

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The air handling unit (AHU), or rooftop unit (RTU) if it's located on the roof, is the heart of a commercial HVAC system. Most commercial cleaning jobs include cleaning both the AHUs/RTUs and their associated ductwork. When estimating these jobs, the commercial project estimator will consider the unit's location and how difficult it is to access (e.g., a hanging AHU), its size, the labor involved in removing the access panels, and of course, how dirty the unit is. ​

Preparation for AHU/RTU cleaning

Before cleaning can take place, lockout/tagout procedures must be implemented in order to ensure a safe work environment.  If there are smoke sensors in the ducts, the system should be put into test mode for the duration of the work. All access panels to the unit are opened, and air filters removed. In order to protect electrical components and the supply and return drops, 2- or 4-mil polyethylene sheeting is placed. 

The cleaning process

Cleaning of the unit begins with a HEPA-filtered dry vacuum. All interior-insulated surfaces are vacuumed in order to remove larger debris. The commercial technician will then apply degreaser to the fan and other metal components inside the unit to remove grease that's been previously applied and has built up over time. A pressure-washer is then taken to the unit, and, if necessary, a scrubbing pad for hard-to-remove debris. 

To clean the unit's heating and cooling coils, a coil cleaner is applied with a sprayer and allowed to sit a few minutes until foaming. Once the foam has worked its magic, the technician uses a pressure-washer to rinse it off at a downward angle, toward the drain pan. The drain pan itself is then cleaned with a pressure washer and wet-vacuum. 

One of the final steps in the process is to ensure that the drain line is properly draining, as overflow from the drain line would fill the drain pan and enter the supply duct line, potentially contributing to mold growth on the insulation. 

When the cleaning is complete, all excess water is wet-vacuumed and dry rags are used to wipe metal surfaces if needed. The unit is then reassembled and all access panels replaced. 

The benefits of air handling unit cleaning

Your building's occupants and your HVAC system will thank you. Cleaning of the air handling unit and its associated ductwork means the minimization of contaminants entering the indoor air, Increased efficiency of the overall HVAC system due to improved air flow, increased ability of the unit to heat and cool occupied spaces, and prolonging the life of the unit. 

Wanna dig deeper? Our commercial air duct cleaning page contains detailed descriptions, before and after photos, and videos of our commercial duct cleaning processes.
​
View Commercial Duct Cleaning Page

Many thanks to our commercial project manager Ben S for lending his expertise to this article. 

Mold is ubiquitous in both indoor and outdoor environments. When temperature and moisture conditions are favorable, mold can grow rapidly, causing much destruction to property and endangering human health. Because basements tend to be damp and dark, an environment conducive to mold growth, this is one of the areas in your home where mold is most likely to be present. Below are some of the most common causes of mold growth in a basement setting. ​

Missing or clogged gutters

Rain gutters are troughs that run the periphery of your roof designed to collect and funnel rainwater. Without gutters, rain simply runs off the edge of the roof and lands near the  foundation, creating the potential for seepage into the basement. Rainwater falling in sheets to the ground around your home can be a powerfully destructive force. Unless your roof has a significant overhang or is located on a fairly steep slope, you'll want gutters and downspouts to divert water away from your home and its foundation. 

When gutters are in place but are clogged, the consequences are similar. Rainwater, rather than being appropriately channeled toward the downspouts, ends up spilling over the sides of the gutters and pooling around the foundation. Once the ground is saturated, the likelihood increases that water will penetrate any existing cracks. Once there, the expansion and contraction that accompanies the freeze-thaw cycle works to enlarge the cracks and cause further deterioration, eventually allowing water intrusion into the basement, and mold growth.

Detached downspouts

Downspouts convey rainwater collected by gutters downward, often discharging it into a sewer pipe that leads to the municipal sewer system. Some downspouts are redirected, via an elbow and an extension to a desired permeable area away from the house, such as into the lawn, a garden, etc, where the rainwater can infiltrate the soil.

A downspout that has become detached due to high winds, ice formation, or simple deterioration, will not serve its purpose of directing water away from the house and instead will allow it to hammer away at the ground encircling the foundation. Mold specialists seeking to identify the source of water intrusion will often have downspouts at the beginning of their checklist. Visible mold in basement corners is a hallmark of detached downspouts. 

Poor land grading

Grading refers to the slope of the land around your home. Ideally, your home will sit at a higher point, with the land sloping downward away from it. This type of grading would cause any water to flow away from your home, toward the lower elevation, preventing pooling around the foundation. An ideal slope is usually considered 1 or 2 percent, depending on the smoothness of the terrain. 

Though new construction must meet lot grading guidelines, property over time can undergo grade shifting as the house and surrounding land settle, and additionally after removal of trees or shrubs, or sometimes in cases of animal activity.

Of course, any of the above conditions that results in a water intrusion event and mold infestation would need to be addressed and corrected before remediation should occur. A qualified mold remediation specialist will have the necessary experience and tools to identify the issue, and help resolve it.
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Wanna learn more about mold services, including mold remediation, inspections, and testing?
Visit Mold Services Page

​ Thanks to our mold remediation specialist Zach C for lending his expertise to this article.

Commercial air ducts, as in an office setting, are often lined with interior insulation for the purpose of noise attenuation and the reduction of heat transfer. Ducts with this insulation on the inside (as opposed to exterior-insulated, or having no insulation at all) are often referred to as "lined ducts." Interior insulation reduces the amount of fan and other system noises heard moving through the ducts, and additionally allows air that is heated or cooled to maintain its temperature while making its way through the ductwork. The twofold benefit is a quieter system for building occupants, and greater overall system efficiency, reducing energy costs.​

Wanna dig deeper? Our commercial air duct cleaning page contains detailed descriptions, before and after photos, and videos of our commercial duct cleaning processes.

View Commercial Duct Cleaning Page
​Many thanks to our commercial project manager Ben S for lending his expertise to this article.