Understanding the Differences Between Negative Air Duct Cleaning and Agitation Air Duct Cleaning

If you're considering cleaning your air ducts, you've probably come across terms like "agitation cleaning" and "negative air cleaning." But what do they actually mean? And which one is right for your home?

At Mile High Ducts, we offer both methods and help our customers choose the one that fits their needs. Here’s a simple breakdown of how each process works and when it makes the most sense to use them.

What Is Agitation Air Duct Cleaning?

Agitation cleaning is a basic method that uses rotating brushes, air whips, or compressed air tools to loosen dust, dirt, and debris from the walls of your ductwork. These particles are then collected using a HEPA-filtered vacuum.

It’s a great option for homes with:

Light dust buildup
Routine maintenance needs
No signs of mold, odors, or allergens

Agitation is effective for surface-level cleaning and can help improve airflow in relatively clean systems. However, since it only loosens debris without strong directional airflow, it may leave particles behind - or in some cases, push dust closer to your furnace, especially in longer duct runs.

What Is Negative Air Duct Cleaning?

Negative air cleaning is a more advanced and thorough method. It involves sealing off your vents and attaching a high-powered vacuum (5,000 CFM) directly next to the furnace to create negative air pressure inside your duct system.

As this vacuum draws air and debris away from the furnace, we use agitation tools (like brushes and air whips) to dislodge particles deep inside the ducts. Those loosened particles are then immediately pulled into the vacuum, rather than recirculating into your home.

This combination of agitation + powerful suction ensures that contaminants are removed efficiently and safely—from the entire system, including hard-to-reach returns and main lines.

This method is ideal for:

Homes with heavy dust buildup
Allergy sufferers or pet owners
Systems with mold, odors, or contaminants
Homes that haven’t been cleaned in several years
New builds or post-renovation, where construction dust, drywall particles, and debris often fill the ductwork

Negative air is the gold-standard in air duct cleaning.

Key Differences at a Glance

Which Method Should You Choose?

If you're doing a routine maintenance clean and your home doesn’t have major dust, odor, or allergy issues, agitation cleaning may be a cost-effective option.

But if you want a deeper, more complete clean - especially after renovations, or if you have pets, allergies, or it’s been years since your last cleaning - negative air is the gold standard. It ensures debris is pulled away from your furnace, not toward it, and completely removed from your home.

Still Not Sure? We're Here to Help

At Mile High Ducts, we’ll never upsell you on something you don’t need. Our team will assess your system and help you choose the right cleaning method for your home and budget.