Ahh, the beauty of the internet. Many home HVAC professionals, both former and current, have shared the secrets of the air duct cleaning business behind the privacy of a computer screen. Bottom line…it’s (mostly) a scam.
One reddit user (silber_nact), a self-proclaimed HVAC service technician states,
In general, duct cleaning is just short of a scam. Of all the homes I’ve work in doing hvac/duct cleaning, I can count on one hand the homes that “needed” a duct cleaning. Most of those where homes that have had multiple dogs for decades. However with that being said, even those homes didn’t see an improvement in air quality, only duct volume(since the animal hair was removed, air could follow more easily).
You have to remember almost all the dust in your ducts is BEFORE your air filter, so it your changing your filter regularly(3-6 month) and you use a good quality filter(Merv 8 or better), The air you breath will be clean.
Just like the National Institute of Health and EPA, this reddit user doesn’t speak in absolutes — there are of course cases where a home HVAC duct cleaning would be appropriate:
With that being said, if the ducts have mold and such filters won’t be enough, and you need to have professional help.
This reddit user then goes on to give advice for improving the indoor air quality:
Here’s what I recommended to any customer asking about duct cleaning.
If someone in the house is having respiratory issues the first thing you do is change your filter and run the fan on the furnace more frequently and wait a few weeks. If they don’t get better, upgrade your filter to a better quality. After a few more weeks if you see no improvement, then I recommend having a company come out and do an air quality test looking for mold, VOC’s, and dust in the air.