The short answer is generally, no. There are cases when you should, but they are usually pretty rare.
Yes, the ductwork may get dusty, but that is not unusual, and you don’t need to clean the ducts because of the dust.
The U. S. Environmental Protection Agency has said that cleaning ductwork has no effect on home residents’ health. Moreover, there is no evidence to suggest that dirty or dusty ductwork adds to the dust in your home. That’s because the dust in the ducts stays in the ducts. The EPA does not recommend having ductwork cleaned, except on an as-needed basis.
There are certain situations when you should consider getting your ducts cleaned: if, for example, your ducts are downright filthy, or they are infested with vermin or you have seen evidence of mold growth, you should get the ductwork cleaned.
Cleaning ductwork is a big and somewhat complicated job that requires specialized knowledge and tools. You want to make sure that the company doing it has been certified by the National Air Duct Cleaning Association (NADCA.)
Moreover, if your ductwork is contaminated and needs to be cleaned, you need to have your entire HVAC system cleaned as well, since your HVAC unit also is exposed to the contaminated air flowing through the ducts.
In fact, the NADCA recommends that having your ducts cleaned should be done only as part of an overall system cleaning. This includes replacing the air filter, cleaning the grilles and diffusers, checking the drain pans and drain lines to make sure they are working properly, checking the heat exchanger and cooling coils, as well as the grills, furnace air plenum, blower motor and other parts.
Doing all this cleaning will cost you anywhere from $500 to $1,000. It usually requires two technicians and takes about three to five hours.
Don’t be tempted by people offering much cheaper rates to do the cleaning. Odds are they aren’t qualified to do the work properly, and that could cause you even more trouble. There is a reason it costs so much: the technicians first must use tools to shake the dirt free so that it can be vacuumed out. Sometimes this involves cutting the ducts open so that the technicians can gain access for the tools.
If this is not done properly, this can create a real mess, including releasing dirt and other debris into your home.