Duct Cleaning

The Accumulation of Contaminants

Air ducts naturally accumulate a variety of airborne particles, including:

• Dust and Dirt: Standard household dust is a mix of dead skin cells, pet dander, lint, and other fine particles.

• Allergens: Pollen, mold spores, and dust mite waste can all enter and settle within the ductwork.

• Microorganisms: In the presence of moisture, ducts can become a breeding ground for mold and bacteria, which release spores and toxins into the air.

• Small Insects: Dust & Spider mites commonly find a home within  the duct system of a home. These small animals cling to dust & debris that are inhaled by customers leading to 

How Duct Cleaning Works

A duct cleaning involves using specialized equipment to dislodge and remove these contaminants from the entire duct system. This process typically uses a combination of powerful vacuums and agitation tools. The vacuums create a negative pressure in the ductwork, while tools like brushes and air whips are used to physically dislodge the debris. The dislodged contaminants are then pushed or pulled into the vacuum and removed from the home. This prevents them from being released back into the indoor environment.

The Impact on IAQ

By removing this reservoir of pollutants, duct cleaning provides a direct and immediate improvement to IAQ. The benefits can include:

• Reduced Allergens: Less dust and fewer allergens in the circulating air can significantly decrease symptoms for people with allergies or asthma.

• Fewer Odors: Musty smells and other unpleasant odors can be caused by microbial growth or accumulated debris in the ducts. Removing these contaminants can lead to a fresher-smelling home.

• Improved Efficiency: While the primary benefit is health-related, clean ducts allow for better airflow, which can make a home's HVAC system run more efficiently.

Understanding The Vacuum Systems

Vacuum systems are the core of the cleaning process. We use two main types, each with a specific purpose and set of considerations.

• Engine-Driven Vacuums: These are the most powerful units available.

  • Duct Cleaning Trucks: These are PTO or separate engine-driven blowers that are permanently mounted. They offer immense power, pulling up to 15,000 CFM at the machine and around 8,000 CFM at the connection.

  • Portable Gas Vacuums: These are smaller, gasoline-powered units (9-20 HP) that produce 5,000-7,000 CFM. Their key advantage is that you can move them closer to the air handler, reducing the hose length and the CFM loss that comes with it.

  • Operational Challenges: Both require leaving a door or window open for the hoses. This can be problematic in extreme weather, leading to complaints about discomfort and potentially causing water damage from rain or snow. It also allows insects and other pests to enter the home. The negative pressure created by these vacuums should not exceed -5" of water column, as this can damage the ductwork.

• Portable Electric Vacuums: These units are essential for situations where an engine-driven vacuum isn't practical.

  • Design: These are electric-powered and require a sealed HEPA filter to ensure that contaminants are not re-circulated into the building. They come in single-blower (2,000-2,500 CFM) and dual-blower (4,000-5,000 CFM) varieties. They also feature a multi-stage filter system to protect the HEPA filter from premature clogging.

  • Limitations: They are less powerful than engine-driven units and their vacuum power decreases with hose length. However, they are ideal for jobs where an external exhaust is not feasible.

The Cleaning Process: Sweeping

Our method is a dry cleaning process known as "sweeping," which uses tools to agitate and move debris toward the vacuum.

• Air Tools: These tools are powered by an air compressor. An effective compressor needs a minimum of 10 CFM of airflow at 150 PSI. Smaller compressors are problematic because they take too long to recharge and quickly drop below the required pressure, making the process slow & inefficient. Large, powerful compressors (up to 45 CFM at 200+ PSI) are extremely effective but the air escaping is also very loud and requires hearing protection.

• Brushes: Brushes are the best tools for dislodging caked-on debris that air tools can't move. They come in three types:

  • Drill-Operated: These are difficult to handle and require two people to operate due to their awkward nature and length (often <30'). They must be used with a cordless drill with a clutch for safety.

  • Motorized Head Assembly: These are easier to manage as the torque is at the brush head itself, but still often require a second person for assistance.

  • Air-Driven: These combine brushing and air sweeping, offering a dual-action cleaning tool.

Best Practices

1. Safety First: Before starting, deactivate the system and shut off the gas.

2. Vacuum Connection: Cut an 8" hole (12"x12" patch is sufficient for repair) near the furnace, or disconnect a branch line, to connect the vacuum hose. The connection point should be at the bottom of the duct to maximize debris removal.

3. Zoning & Sealing: Isolate the system by using balloons or foam to separate the supply and return sides. Temporarily seal each register opening with plastic film or paper to create increased velocity and more effective cleaning.

4. Cleaning Order: Always clean in the opposite direction of normal airflow. The protocol is: supply branch lines first, then supply main lines, followed by return branch lines, and finally the return main lines.

5. Air Handler: The air handler, coils, and blower motor are often the dirtiest parts of the system and must be thoroughly cleaned. Ignoring them makes the entire job ineffective.

6. Mold & Special Protocols: For mold remediations, additional steps are required:

   • Cleaning: Perform additional passes with both motorized tools and air tools.

   • Disinfectants: Use approved disinfectant sprays, but only with the customer’s written consent.

   • Encapsulants: Apply encapsulating sealers to trap remaining particulate matter. Be extremely careful with overspray, as it is difficult to remove and can damage furniture.

   • Wet-Wiping: Use a wet cloth with a cleaning product to wipe the interior of the duct for clearance testing.

7. Final Steps: Patch all penetrations with sheet metal patches (minimum of 8 screws and UL-listed tape). Avoid mastic for future cleanability.

8. Expectation Setting: Always discuss expectations with the customer beforehand. Explain that it is a "dry" cleaning process and that while we remove as much debris as possible, a wet towel will likely still pick up some residue. This manages expectations and builds trust.