Should You Get Your Ducts Cleaned?

As we close in on the heating season, I have gotten a number of questions about the value of duct cleaning. Every home with a forced air heating system has duct work that distributes the heat to various rooms and hallways. The ductwork is made of sheet metal formed into square or rectangular sections joined together. This is called a plenum, from which round metal secondary sections run to each floor, wall or in some cases ceiling vents or “boots,” as they are called in the trades. As the heated or air conditioned air circulates through these metal runs, they collect dust, hair, animal dander and any number of other “articles,” including toys, tools and household items. Every reputable builder either gets the ducts cleaned themselves or offers this to new home buyers because it is well known that tools, coffee cups and general construction debris ends up in new home ducting.

There is some amount of “pro and con” with respect to getting your ducts cleaned. A number of years ago CMHC and the US EPA did a joint study on the value of duct cleaning and the results of the test arrived at the following conclusion. “…researchers observed little or no discernable difference in the
concentrations of house airborne particles or in the duct airflows due to duct cleaning.  This is because the ducts are just metal passages, they cannot create dust. Most household dust comes from outdoors that has been tracked in or enters through windows and other openings.” The study went on to say that
every time you walk around in your home you raise a tiny, almost invisible cloud of dust particles wherever you go.

There are various conditions when getting your ducts cleaned may be beneficial. The most serious issue is the growth of mould in your ducts. This is often caused by dampness or water getting into them. Sometimes insulated ducts can retain dampness from higher levels of humidity. Tiny four legged “visitors” have been known to nest and die in ducting, causing an odour in the home. Foreign matter inside your duct can block the actual air flow in the system. If you have bought a home that was formerly occupied by owners with a number of pets, the build-up of animal hair and dander may be excessive. It is well known that the return air ducts, which move air at a far slower rate than your supply ducts, will be dirtier. That said, and further to the study quoted, neither CMHC nor the US EPA have any research or testing that confirms that getting your ducts cleaned can improve the air quality in your home. It is also very doubtful that getting your ducts cleaned will improve the efficiency of your heating or cooling
system.

If you feel that any of the above issues may be present then a cleaning by a professional duct cleaning service may help. The duct cleaning business has grown to a multi-billion dollar industry with companies like Enviro-Clean and ServiceMaster, which are international organizations that have franchises all over
the world. Select two or three reputable duct cleaning companies from the phone  book or on-line. Call each one and compare their service and prices. If any one of them makes claims of improving your air quality or the efficiency of your heating system, scratch them off your list. Ask for some references and call these numbers. Keep in mind though that the referenced are likely to be favourable, since rarely does any business supply marginal references.  Most of the reputable duct cleaning services will access every floor duct and remove the covers from your return ducts. They should inspect the system for any contaminated materials like asbestos and advise you if they find it. The franchise companies I have seen all use outside or truck mounted vacuum equipment.  Some use a Hepa-Filtered vacuum that discharges to the exterior. They are cleaning an area of your home, floor covering and clean dress with “house
booties” or different shoes for their staff are commonly used. There is an organization that has a set of standards for duct cleaning. The “HVAC Inspection, Maintenance & Restoration Association” Go to www.nadca.com for more information. They actually offer a certification process for an “Air Systems
Cleaning Specialist” and another certification for a Certified Ventilation Inspector” that duct cleaning contractors can add to their credentials.  There is no real need to clean your ducts unless you suspect moisture, air quality issues or blockage is present. The jury is out on the air quality benefits and only if you get your furnace components cleaned at the same time will you possibly help improve the air movement in your home. It comes down to your personal life style; do you feel better if the circulated air in your home is being moved through a clean metal supply system or not. When asked, I usually tell our
clients that if they have a concern, start with a good HEPA style filter as a replacement for a standard furnace filter. Lastly, refrain from any air fresheners or chemical treatments, unless you have investigated them fully.