Duct cleaning?

Is this really a thing?

Or is it snake oil?

I am serious, my wife keeps harping about getting it done

We had it done when we moved into our new build house.
Looked like everything was tossed in the ducts if it was not needed.
After doing some remodeling last year, had it done again.
It really reduced the amount of dust in the house.
When finding a duct cleaner company, look out for those that are trying to upgrade your HVAC system.
One company told us they sell new heaters/ac units and they would evaluate all that when they came in.
I told them I had just had the relatively new system serviced and I did not want them inspecting my furnace.
Then they got real vague about setting an appointment for the ducts.

It is very real.

It can have a huge impact on indoor air quality. In houses that have never had it done, the amount of dust, dirt and debris removed can be frightening.

I always recommend it after every inspection I do, because you do not know the history of the house. Both general inspections and especially when I am doing mold testing. (Yes, mold is a problem in Colorado, despite our lack of humidity).

There may have been plants or animals that had allergens that affect you or your family. They may have been slobs that rarely cleaned.

With any kind of organic matter in the ducts, if you add water from a spill, leak or condensation, you can have bacterial or fungal growth develop.

If you have never had it done, do it.

Does it need to be done annually? That depends. If you live in an area that is prone to more airborne dust and particulate matter, probably. Think a farm house during plowing or harvest. Or a home next to a highway that always has windows open.

If you decide to do it, find a reputable company, not some knucklehead with a shop-vac and a toilet brush.