Duct Cleaning is a Scam

Duct Cleaning – Scam or Legitimate Service?

Every month, without fail, I receive at least 3 or 4 solicitations for duct cleaning services.  They always provide a good chuckle before I toss them into the recycling bin.   However, it recently occurred to me that many people must hire these companies or they wouldn’t keep spending the money on advertisements.  Thus, I felt compelled to provide a bit of education on the merits, or lack thereof, regarding duct cleaning.Duct cleaning scam

First, let’s just point out the obvious.  Duct cleaning companies have a terrible habit of massive upselling at the customer’s home.  Take a quick glance at the next 2 or 3 duct cleaning coupons or ads you receive.  Almost without exception, they advertise a price of around $100.  I’ve even seen some as low as $37.00.

Here’s the problem.  Even if they were running a non-profit and paying their employees minimum wage, it would still be impossible to stay in business charging only $100/house.  This wouldn’t even cover the cost of labor and gas to drive to the home and setup the equipment.  How is this addressed?  Upselling.  Massive upselling.  A typical duct cleaning project advertised as only $100 will quickly turn into a $350 project once they factor in the caveats found in the limitations.

Okay, but hey, they’re providing a good service right?

Let’s look at the science behind duct cleaning.  If you read their ads, the big problem with ducts is that they’re full of nasty accumulations of dust, mold and dust mites.  And, so the claim goes, these unpleasant particulates are blown throughout your house every time the furnace runs.

Mold doesn’t like ducts.

Duct cleaning & dirty ducts

One of the primary claims promulgated by duct cleaning companies is their ability to remove mold growth.   Is this true?  Most ducts that are capable of undergoing duct cleaning are made from metal.  Metal, of course, isn’t a very good food source for mold.  It suffers from two problems.  First, it lacks the digestible components necessary for mold to flourish.  Second, because metal can’t absorb moisture, it is unlikely to provide conditions conducive to mold growth.  Now granted, mold could grow on the dust that settles on top of the metal.  We’ll explore that next.

Mold likes moisture.

Mold growth cannot occur without available moisture.  Thankfully, the amount of moisture required by mold growth is usually in excess of the level of humidity preferred by humans.  Thus, moisture conditions conducive to mold growth only occur when something has gone awry with the home.  Many things can go wrong in a home that lead to excess moisture.  Roof leaks, plumbing leaks, poor ventilation, etc.  However, in all but extremely rare circumstances, the conditions inside your ducts will be far drier than anywhere else in your home.

Settled dust remains settled.

Why does dust accumulate in your ducts in the first place?  The answer to this is the biggest reason why duct cleaning is worthless.  The reason dust accumulated in the ducts in the first place is because the wind speed is insufficient to keep the particulates airborne.  The dust particles are moving throughout the duct system but eventually fall out and deposit onto the duct.  Why would these same particles of dust suddenly feel inspired to jump into the wind stream and float off into the home?

A scientist recently tested this and found an interesting conclusion.  Wind speeds in excess of 160mph are required to move settled dust back into the air stream.  I don’t what brand of HVAC equipment you bought, reaching these speeds within a residential duct system is impossible.  Unless, of course, you’re using a leaf blower instead…

Duct cleaning with a leaf blower.

Still not convinced?

“Duct cleaning has never been shown to actually prevent health problems.  Neither do studies conclusively demonstrate that particle (e.g., dust) levels in homes increase because of dirty air ducts.” — EPA

Caveats. Ok, not all duct cleaning is worthless.  Occasions do exist that call for duct cleaning.  These include asbestos cleanup or post construction cleanup.  Other conditions, like rodent infestation or water damage, are not conducive to duct cleaning, because direct replacement is more effective.

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