Yellow Pages Home Improvement
Find Home Improvement Resources near you...
What is the job?
City or Zip within miles
Home Improvement Calculators

Home Improvement Calculators Home Improvement Calculators View our Home Improvement Calculators




Air Conditioning Contractors
Local Air Conditioning Contractors in your area
Heating & Air Conditioning Contractors
Local Heating & Air Conditioning Contractors in your area
Heating Contractors
Local Heating Contractors in your area

How to Clean Air Conditioning Ducts

Air conditioning ducts require their own maintenance regimens, which are often distinct from the kind of basic measures used on filters and external parts. If regular cleaning and replacing of the filters does little to reduce the amount of dust or debris in your home, it may be time to look at the conduits that carry treated air from room to room. Anyone who has dealt with chronic allergies knows firsthand that the spores and microbes responsible for such discomfort can hide almost anywhere.

The problem is that many homeowners do not know where to begin when it comes to duct cleaning. A wide array of so-called professional services advertise in newspapers and local magazines, but with few exceptions, these are simple “blow and go” outfits that provide little in the way of substantive cleaning. If you want to bypass such scams and work with experienced experts, it’s essential to understand the basics of air ducts and how they work.

One of the most common mistakes with air conditioning ducts is applying the wrong kind of treatment for the materials in your home. Air conditioning ducts can be made of fiberboard, fiberglass or sheet metal, and each comes with its rules for effective cleaning. Apply a microbial biocide to a fiberglass duct liner, for instance, and you may find the problem recurs within a matter of days – fiberglass is far too porous to eliminate mold growths in this way.

Need a Heating and Air Contractor?
Find Heating and Air Contractors in your area:
Your zip code or city:

The basic rule of thumb is that certain duct types simply lend themselves better to cleaning, while others should be replaced. Metal is the easiest to clean because of its hardy constitution, while fiberglass and fiberboard may represent real headaches if mold spores have been allowed to multiply. All three varieties can be addressed effectively with measures recommended by the National Air Duct Cleaners Association (NADCA), however, so identify which materials your home has before you begin.

If cleaning is recommended, you will want to work with people who can offer the kind of specialized blowers, vacuums, brushes and filters necessary for safe and effective cleansing. Most such companies place the entire system under negative pressure, drawing dust and debris to a central repository before going in with mechanical measures by hand. This kind of brute-force pressure method is only recommended if safeguards have been put in place to protect your home from flying dust and particulates, however, so stick with services that vent into the open air instead of your home.

If you or someone you have hired is considering using a sealant designed to keep mold at bay indefinitely, you should know that most trade organizations discourage this practice. For homes where the sealant is being used as a band-aid over an existing mold problem, the chances of success are slim. Worse, because most such sealants cannot be evenly applied, it’s not unusual for such chemical coatings to break down over and even become dislodged, further polluting your home’s air supply.

For insulated ducts that make use of soft layers, it is especially essential to keep moisture at bay. Fiberglass can breed mold and bacteria rather easily if repeated sources of moisture are introduced, so you may want to consider additional ventilation and barriers to keep this problem to a minimum. If the problem continues and your family shows symptoms of infection, it may be time to replace the ducts and go with bare sheet metal that can take a liquid application of biocidal sanitizer when needed. A word of warning, however – chemicals such as these can be noxious and irritating, so be sure you are working with professionals who know how to keep it out of your home’s circulating air.

Indoor air is often far more polluted than outdoor air, sometimes be a factor of 50 or greater. Maintaining the health of your home’s HVAC system is one of the simplest measures you can take to ensure no unwanted particulates are being bred into your home’s air supply. Do it yourself with patience and care, or hire professionals who can give you a thorough cleaning and aftercare. Often the incidence of cough, cold and asthma will reduce dramatically after effective air conditioning duct maintenance.


Find a local Heating and Air contractor.
View more Heating and Air articles.