Is the air inside your home sick?
From time to time we hear of people complaining that their HVAC system is causing problems with their respiratory health. And occasionally we see news reports of “sick” office buildings. We are often asked if it is good practice to clean the air ducts in the house to prevent issues.
Simple question but the answer is complicated. What we know about air duct cleaning is still in the early stages, so we’re not going to offer blanket recommendations about whether or not to clean your ducts. The Environmental Protection Agency (EPA) has not been able to determine if cleaning air ducts prevents health problems.
Studies by the EPA have not conclusively shown that particle, such as dust, increase in homes due to dirty air ducts. This is primarily because much of the dirt in air ducts sticks to the surfaces of the duct and does not necessarily enter the living space.
It is important to keep in mind that dirty air ducts are only one of many possible sources of particles that are present in homes. According to the EPA, “Pollutants that enter the home both from outdoors and indoor activities such as cooking, cleaning, smoking, or just moving around can cause greater exposure to contaminants than dirty air ducts. Moreover, there is no evidence that a light amount of household dust or other particulate matter in air ducts poses any risk to your health.”
There are some signs to look for that would require you to clean your ducts.
One indication would be substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system.
There are several important points to understand concerning mold detection in heating and cooling systems:
Sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.
You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can only be made by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories can tell you whether a sample sent to them on a clear strip of sticky household tape is mold or simply something that looks like mold.
If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.
If the conditions causing the mold growth in the first place are not corrected, the mold will grow back.
Your ducts should also be cleaned if they have been infested with rodents or insects. Lastly, if the ducts are clogged with excessive amounts of dust and debris and/or you see evidence of particles actually coming out of the registers would be an indication that the ducts need to be cleaned.
As with any service, be sure to research the company you hire to do the work. Depending on where you live, the size of your system, the accessibility to the system and the level of dirt and dust in the ducts, cost can vary greatly.
A good rule of thumb to go by is that if no one in your home is suffering from allergies or unexplained symptoms or illnesses and if, after a visual inspection of the inside of the ducts, you see no signs of large deposits of dust or mold (no musty odor or visible mold growth), having your air ducts cleaned is probably unnecessary. It is normal for the return registers to get dusty as air is pulled through the grate. This is not a sign that your air ducts are contaminated with heavy deposits of dust or debris; the registers can be easily vacuumed or removed and cleaned.
On the other hand, if family members are experiencing unusual or unexplained symptoms or illnesses that you think might be related to the environment of your home, you should first discuss the situation with your doctor.
The EPA has published the following publications for guidance on identifying possible indoor air quality problems and ways to prevent or fix them.
If you think duct cleaning might be a good idea for your home, but you are not sure, talk to a professional. The company that services your heating and cooling system can be a good source of information. You may also want to contact professional duct cleaning service providers and ask them about the services they provide.