As an expert in the field of air duct cleaning, I can confidently say that the process is not essential to health, nor does it reduce energy bills by improving system efficiency. While it may seem intuitive to clean the ducts in order to ensure clean air coming out of the vents, the truth is that the dust that settles in the ventilation system usually stays where it is and is unlikely to reach the air unless it changes. In most cases, dust is inert and harmless, and removing it with cleaning equipment actually creates major problems. Little research has been done on the effects of duct cleaning, but studies conducted by the governments of the United States and Canada and health professionals who have researched duct cleaning do not support it as a routine measure. The few independent research conducted on duct cleaning indicates that the process accumulates so much dust that it creates a greater problem than it solves. The best way to keep dust, allergens, and other particles out of the home is to change air filters frequently.
With a newly installed system or one in a house you just moved into, check the filter once a month to determine how quickly it gets dirty at different times of the year. Most should be replaced every two to three months. Cleaning heating and cooling equipment (heat exchangers, cooling coils, condensate drain pans, fan motors, fan blades and fan housings) can also provide some benefits. While much of the energy used to power heating and cooling equipment is wasted due to equipment inefficiency, poor insulation, leaks around doors and windows, and unsealed ductwork, cleaning and maintaining heating and air conditioning equipment can provide some small benefits. The CMHC researchers found that when duct cleaners also cleaned the fan blades, there was a small reduction of particles suspended in the air. Cleaning the fan could also slightly improve the energy efficiency of the system.
The same goes for the evaporator coils in your home cooling system. Evaporator coils cause condensation and dehumidify air before it circulates around the house. Condensed moisture can cause dust and other particles to adhere to the coils and accumulate in them. In addition, by cleaning the collector tray (and the draining nozzle of the tray) located under the coils, it is ensured that dirt does not accumulate and enter the system. It also prevents water from accumulating in and under the coils, which can cause mold problems. If any member of your household has specific health problems such as allergies or asthma, consult your doctor first.
It is important to identify the problem so that your doctor can suggest alternatives to cleaning your ducts. Start by identifying if your ducts are part of your problem (they probably aren't) and if cleaning them will help (it probably isn't). If you suspect that you have a mold problem either because of visible growth or because of a musty smell that constantly comes out of your supply grilles then cleaning your ducts won't do much good if it doesn't get rid of your mold. Mold starts with a moisture problem and your ducts themselves are unlikely to be causing this issue. The most likely culprits are your cooling system's evaporator coils which your heating and air conditioning contractor and most duct cleaning companies can inspect and maintain.
Leaky return ducts can also introduce moisture. Duct cleaning isn't necessarily a bad idea but truth be told it's not necessary in most cases. In fact cleaning normally dusty ducts provides no real value. If done properly however duct cleaning can be useful in limited situations. Ordering things only helps to a certain extent if in first place you keep buying too much.
