Should I Get My Heating Ducts Cleaned?

Q. I'm writing to you from Barbados, a place that never gets cold. Some homes here have heating ducts, and I'm wondering how are heating ducts cleaned? What are the benefits to a home from getting your ducts cleaned? (from James in Barbados)

A. Good question, James. Many homeowners want to keep their homes as dust-free as possible, and that includes eliminating pollens, pet hair, and other irritants from the air. It seems rather intuitive that you would want to occasionally clean the warm air -- or supply ducts -- as well as your cold air -- or return ducts. It makes sense to get rid of any nastiness in these sheet metal conduits just like you would vacuum your house or shampoo the rugs.

Unfortunately, cleaning your home's heating ducts haven't been shown by a number of scientific and independent studies to have much impact on better air quality. It's also not been shown to reduce energy costs, another common claim of duct cleaning companies. And why would that be? Experts tell us that people, pets, and other air polluters are constantly making their messes outside your home's heating ducts. Changing how clean your ducts are won't change that situation at all outside the ducts. And the energy cost reductions? Well, what dust or debris there may be in your ducts usually has zero impact on hot air flow or on the cold air return to your furnace or boiler -- unless you have a major obstruction in the ductwork.

Many commercial companies advertise big health benefits and energy savings from cleaning your ducts, but you should be sceptical. We found a great article from the Canada Mortgage and Housing Association, Should You Get Your Heating Ducts Cleaned?, and it raises doubts about the process except in some cases:

• Your house has a water problem and water has created mold in your heating ducts. You'll want to take care of the source of the moisture first, then have the mold removed from your ductwork.
• You are moving into new construction and you want to make sure that all construction debris is removed, from plaster dust and sheetrock screws to the odd left-behind worker's lunchbag, coffee cup, or soda can.
• There is a major blockage in the airflow from your furnace. Sometimes a good cleaning can remove sudden blockages, from whatever cause, in your system.
• Your return air registers seem to be accumulating a lot of debris and you want them to be cleared out. Return registers, with slower moving air, can become dirtier than supply ducts.

Use warm water and a common household cleaner (we prefer natural cleaners like inexpensive white vinegar) to clean your heating duct outlets and grates -- and feel free to reach into the duct with your cleaning. You might rescue marbles, pencils, and small toys that have fallen through the grates, too!

If you do have a company clean your heating ducts, for whatever reason you want professionals to make your ductwork squeaky clean (and many of our experts say you should save your money and skip the cleaning), make sure they are properly licensed and bonded workers and get some homeowner testimonials for the reliability of their work. Some companies use in-duct TV cameras to show you the spic-and-span results of their cleaning, and we like that proof that their work was done well.

One caution: some companies will try to sell you fogging or spraying services after the cleaning, and there are no biocide treatments that are endorsed by independent or government agencies. Save your money and resist purchasing such after-cleaning applications as they are not proven to be effective in eliminating or reducing bacteria or mold growth. In fact, such widespread spraying of chemical agents into your ductwork system is a bad idea for your home's air quality, and that's precisely why you would want your heating ducts cleaned in the first place. 

Photo credits: Matheson Heating, Steamatic Services of Joplin, Can Do Mechanical