We’re going to learn the differences between the two main methods of duct cleaning: contact cleaning and negative air cleaning. Each method uses different types of equipment and techniques. So, how do you choose which one is best? The answer depends on several factors — your budget, cleaning preference, duct size, and future maintenance plans all play a role in the decision.
For 24/7 trusted air duct cleaning services, visit https://airductcleaning-atl.com/
In future lessons we’ll go over the different pieces of equipment in detail, but for now I’ll explain how each method works.
Negative Air Cleaning
In negative air cleaning, debris is loosened in the duct by either using a rotating brush or high-pressure air to dislodge it. In either case, our TurboJet uses negative air pressure to pull the debris toward the unit. This negative pressure is created by the TurboJet and by placing plugs in vents within the section being cleaned. You can learn more about this process in our professional air duct cleaning guide for detailed steps and best practices.
Air moves from a high-pressure environment to a low one—this is what we feel when it’s windy. The TurboJet creates the low-pressure environment, and the air in the ducts moves to this low pressure. The moving air is measured by cubic feet per minute, or CFM.
Our TurboJet SuperMax can move air through the unit at a fast 3,500 cubic feet of air per minute. In an average 3,000 square foot home with eight-foot ceilings, there’s around twenty-four thousand cubic feet of air. A TurboJet SuperMax can move all the air in the house through the unit in about six and a half minutes. For comparison, the average air conditioner in the home moves the air through the ducts at around a paltry 400 CFM—that’s quite a difference.
Contact Cleaning (Overview and Metrics)
The other method of cleaning is contact cleaning—cleaning using suction. Suction is measured as suction width using a water gauge (and if you didn’t already know, air is a fluid). This suction is produced using a smaller opening, like in the hose in our Vent Vac or Duct Master.
An easy way to remember which equipment does what: think wide opening = CFM; narrow opening = suction. Each piece of equipment is rated for both CFM and suction lift using a water gauge and expressed in inches.
For example, our TurboJet SuperMax has a CFM rating of 3,500 CFM with filters, but it only has a suction lift of 5.1 inches—good for moving large amounts of air, not so good at suction power. Our Duct Master, on the other hand, has a rating of only 420 CFM, but it has a suction lift of 75 inches. This is going to pull the surrounding debris into the collection hose and to the Duct Master. This makes it terrific for contact cleaning.
Negative Air Cleaning (Process and Sequence)
Negative air cleaning works by moving air from a high-pressure environment to a lower one. When a TurboJet is attached to the duct system, and with the help of foam plugs in the other vents and grills, it creates a seal. When the TurboJet is turned on, it pulls the air through the ducts to the machine using negative pressure. Many homeowners misunderstand how this method actually works, which is why exploring common air duct cleaning myths can help clarify the facts.
You can then use several different methods to agitate the debris in the ducts:
- Option one: You can loosen the debris by using our Sidewinder or Air Whisk along with an air compressor and use high-pressure air to loosen the debris. Once the debris is loosened, it’s sent by negative pressure to the TurboJet.
- Option two: You can use our Cobra Power Brush System and brush along the ducts. The brush contacts the side walls of the duct, agitating the debris loose, and the moving air sends it to the TurboJet.
Keep in mind, in negative air cleaning you are moving debris through the ducts, so you want to clean them by doing the return ducts first and then the supply ducts. If you clean the supplies first and then you clean the returns, you could send the debris back into the supply ducts you’ve already cleaned.
Contact Cleaning (Process)
Contact cleaning is another method of cleaning the ducts. This is where you’ll use brushes to come in contact with the ducts and then suction power through the hose to bring the debris back to the machine. Contact cleaning does not involve placing any plugs. You don’t need to know the duct layout of the home, and it doesn’t matter if you start with the supply ducts or the return ducts. You just go room to room and clean the ducts connected to that room.
Contact Cleaning Equipment
- Duct Master: This uses a motorized brush to loosen the debris inside the duct, along with incredible suction power to pull that debris through the attached hose.
- Truck Master: This is a special piece of equipment for those who have truck-mounted carpet cleaning equipment. Keep in mind, this will not work with portable equipment. It works in the same way as the Duct Master, but it’s designed to send the debris to a carpet cleaning truck’s recovery tank.
Dryer Vent Cleaning
For cleaning dryer vents, we have the VentVac 4×4. This was designed to clean laundry exhaust ducts. It uses a contact-cleaning brush to loosen the debris, which is then sent back to the machine.
Learn More
To learn more about each of these pieces of equipment, we have lessons for each one showing how to set up and operate them. And if you have any questions about the cleaning methods, give us a call and we’ll be happy to help. In our next lesson, we will discuss our negative air machines—the Air Duct Cleaning ATL
