Air Duct Cleaning Can’t Solve Everything

If air ducts are contaminated with mold growth or contaminated water, they often need to be replaced instead of being cleaned.

There are a lot of variables to consider when making that decision, but I often hear HVAC companies offering to clean ducts regardless of the severity of the contamination.

The flexible ducts in this video are the most common type we see in Houston homes, and they’re far more difficult to effectively clean.

If they were made of sheet metal with insulation on the outside of the duct, it would make cleaning far more effective.

Sheet metal ducts are fairly similar to the stainless steel counters and tables found in commercial kitchens – although sheet metal ducts are typically made of galvanized steel.

If harmful bacteria, viruses, or mold come into direct contact with stainless steel prep stations in kitchens, they get thoroughly cleaned. It would be ridiculous to throw out the stainless steel tables just because some raw chicken was placed on them.

While stainless steel is far more expensive and corrosion-resistant, it’s a helpful comparison to understand why galvanized steel ducts can usually be sufficiently cleaned after a leak or mold problem (assuming they’re not lined and the insulation isn’t contaminated.)

However, flexible ducts are nothing like solid metal substrates such as a kitchen prep table.

In fact, duct cleaning equipment can actually damage the lining of flexible ducts, which is both difficult to identify and risky for indoor air quality.

They’re easy to puncture, so thoroughly cleaning them is difficult and can permanently damage them.

Adding moisture to flexible ducts, such as water and detergent for cleaning purposes, is risky. (Don’t fog them with anti-microbials in order to “clean” them either.)

The inner lining is not flat like sheet metal ducts. There are ridges, so proper cleaning and drying is not likely to be successful.

Also, flexible ducts are hung with narrow straps that can’t support much weight. When too much weight is added to the duct, it’ll compress the duct insulation and potentially permanently damage them.

When mold grows on a surface, it needs to be physically removed. Then the surface needs to be cleaned, dried, and also verified to be clean.

Removing mold from the inner lining of a flexible air duct, cleaning it, drying it, and verifying that it has been returned to “normal” again typically isn’t practical.