What Is Duct Cleaning and Why Is It Important?

by Bob and RodMan, of The Bob and RodMan Home Show on 920 AM-WGKA

The thought of spring cleaning inspires images of spic-and-span woodwork, glistening countertops, leaf- and litter-free decks and serious dust bunny hunts in every nook and cranny. New paint, new planting and an impressive refurbishment of all visible surfaces are the heart of the program. Every few years, however, a little stealth cleaning is required. One vital, but invisible, part of the home needs periodic attention. However effective your heating and air filter might be, periodic duct cleaning should be on the home maintenance schedule.

Unless there are specific circumstances that call for increased frequency it is probably okay to schedule duct cleaning every two or three years. Some reasons to increase the frequency include: home occupants with mold sensitivity or asthma, young children in the home, adults homebound due to illness, pets kept primarily indoors and smokers in the home. Naturally, it’s a good idea to schedule a duct cleaning upon moving into a new home or in response to interior flooding.

In some ways the term “duct cleaning” can be a bit misleading. Naturally, both the supply ducts—the ones from the air handler to the vents—and the return ducts—the ones leading from the interior of the home back to the air handler—are the most obvious components of the system and will require attention. But so do the fan compartment of the air handler and any plenums. Plenums are duct boxes into which the separate ducts connect for distribution of conditioned air on its return to the air handler. Duct cleaning that is limited to running a vacuum hose into the return or into the supply ducts is only minimally effective. Thorough duct cleaning may even require some disassembly of the fan system and certainly must include special attention to the plenum. Some years ago, I inspected an HVAC system where the ducts themselves appeared clean, but the fan compartment and the return plenum contained enough dog hair to knit several sweaters. Granted, this condition came about due to an absent filter, but it was found in a system that had reportedly been recently “cleaned.”

When qualifying a duct-cleaning contractor, be sure to review the specific services provided and ensure in comparing pricing that it is on an apples-to-apples basis. The cleaner in the above mentioned case might have been a bargain, but he neither adequately cleaned the system nor noted that a major part of the system—the air filter—was missing. Not much of a bargain after all.

A couple of comments on the ducts themselves are required. Rigid metal ducting with adequate insulation wrapped and taped on the outside of the ducts will provide the most efficient and the most easily cleaned system. Flexible, self-insulated ducting is difficult to clean, susceptible to damage and restricts airflow. The introduction of insulation board within the duct system increases both catch points for detritus and likely areas for mold growth. The long-term benefits of rigid metal ducting, properly insulated, far outweigh the initially greater price.

Don’t forget that clothes dryer duct while you’re at it. Collected lint cuts down on dryer effectiveness and is a fire hazard. Getting both jobs done at the same time should save some money too. Reduce maintenance and save money; a pretty good combination.

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