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Air duct cleaning
By B. Leslie Baird
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Follow these steps if taking air duct cleaning into your own hands.
Estimated time
Difficulty
Frequency
As needed
Cost
Tools
- HEPA-filter vacuum with long hose and brush attachments
- Flat-head or Phillips screwdriver
- Duct tape
- Heavy-duty rubber gloves
- Bucket of soapy water
- Cleaning rags
- Stepladder
- A friend to lend a helping hand (optional)
The thought of the dust and debris that must be building up in your home’s air ducts may be making you eager for air duct cleaning. But be aware that a poorly done job can make air quality matters worse.
To clean or not to clean
Should you even clean your air ducts? Common sense suggests your home’s air quality will only get better with sparkling ductwork. But improper cleaning can knock loose dirt that might otherwise remain attached harmlessly to duct surfaces.
And consider this: According to the Environmental Protection Agency (EPA), air duct cleaning has not been conclusively shown to prevent or eliminate health problems. Neither do studies conclusively demonstrate that dust levels in homes increase because of dirty air ducts or go down after cleaning. Outdoor and indoor activity can cause greater exposure to pollutants and contaminants than dirty air ducts alone. The best way to care for your air ducts is by preventing dirt from entering.
The EPA does recommend air duct cleaning for a handful of situations, however, and the root cause to be addressed:
- If ducts exhibit visible mold growth
- If ducts are infested with vermin
- If ducts are excessively clogged
- If ducts are releasing dust or debris from the vents
In these cases, however, a complete cleaning is recommended—one that includes not only the ducts but the heating and cooling coils, condensate drain pans, fan motor and fan housing, and the air handling unit—and that’s a job best left to a qualified professional who follows the standards of the National Air Duct Cleaners Association (NADCA).
So what can you safely do yourself? Cleaning your ductwork’s supply and return registers of visible dirt is always a good idea. And vacuuming and wiping what you can see of your ductwork can give you a sense of potential problems. Follow along for tips on doing it well.
Note: Don’t attempt to clean your own ducts if they are made of anything other than sheet metal. Ducts constructed with fiberglass duct board or fiberglass duct liner can be easily damaged.
Air duct cleaning terminology
Learning how to clean air ducts involves some terminology. Air ducts have both supply and return registers. To determine which type of duct you’re working on, turn on the fan for your furnace system. If air is coming out of the vent, it’s a supply. If you feel air pulling into the vent, it’s a return.
Supply registers. These vents provide heating or cooling to each room. These may be located on the floor, ceiling or lower wall.
Return registers. These vents draw air from the home back into the system for circulation. Returns are larger than supplies. Most homes have at least two returns. Multiple-story homes may have one return on each level.
Step 1. Prepare vacuum
If your vacuum is a bag style, be sure to use a fresh bag for maximum suction.
Note: Use a vacuum with a “True HEPA” filter; any other type may simply vent dirt particles into your living space.
Tip: If the vacuum hoses or attachments don’t fit snuggly, use duct tape to secure them tightly in place. This step is important because if the brush falls off the hose while you are cleaning the duct, you may not be able to retrieve it.
Step 2. Turn system off
You can turn the HVAC system off at the thermostat. This prevents the blower from starting and covering you with loosened debris.
Note: Remember to turn the system back on when you’re finished.
Step 3. Remove supply or return vent cover
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Floor covers can typically be lifted up without the use of tools.
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Wall covers usually have two screws holding them in place. Use a screwdriver to help you remove wall covers.
Step 4. Wash vent or register cover
Slip on the heavy-duty rubber gloves and use a cleaning rag dampened with the warm, soapy water to gently wipe away buildup from the cover. It is best to avoid harsh chemicals as those can cause damage.
Be sure to completely dry anything you wash to prevent mold and mildew growth.
Tips:
- Don’t scrub painted covers; the paint may chip off.
- Protect your hands with gloves; edges may be sharp.
- Allow the cover to dry while you clean the duct itself.
Step 5. Vacuum inside of vent
Still wearing the heavy-duty rubber gloves, begin vacuuming all of the accessible inside surfaces.
Note: Some return registers have filters under the cover. If yours does, remove the filter to access the vent. While you’re at it, clean the filter (if washable) or replace it with a fresh one if disposable. Learn with our step-by-step guide.
Next, work the flexible hose with the brush attachment as far into the duct as you can without it getting stuck. You should be able to reach down a few feet, but do not force it. Carefully move the hose back and forth while vacuuming to reach as much of the interior as possible.
Note: If supplies or returns are located in the ceiling or high up on walls, a stepladder will be needed. A long vacuum hose will allow you to leave the vacuum on the floor while working. You can enlist the help of a friend to help you hold the vacuum or to spot you on the stepladder. If you are not comfortable with working on a stepladder or if you have high ceilings, leave the job to an professional.
Step 6. Wipe down inside of vent (optional)
Use the cleaning rag dampened with soapy water to wipe down the accessible areas of the ductwork.
Dry the cleaned areas well with a fresh rag. Mold or mildew could form if ductwork remains damp.
WARNING: Do not reach too deeply into the ductwork. Angles in the duct could cause your arm to become trapped.
Step 7. Replace cover
Once the cover is dry, replace it. Next, move on to the next supply or return.
Tip: Changing your furnace filter on a regular basis reduces the overall dust and debris that can accumulate in a furnace system. The filter in a furnace is used in both heating and cooling cycles.
Getting the most from professional air duct cleaning
If you decide to go with a professional cleaner, follow these tips for getting the job done right:
Beware of lowball offers. According to the National Air Duct Cleaners Association (NADCA), a reputable company will charge $400 to $1,000 to clean a typical 2,000-square-foot house. This should include cleaning not only the ductwork and any grilles or registers, but the blower motor, heat exchanger, evaporator coil, drain and pan, and replacement of filters. Get more tips on avoiding air duct cleaning scams.
Ask for evidence of any mold or contamination, and then ask to see evidence that the problem has been eliminated after the job is done. Many firms offer before and after video.
Select a company that complies with NADCA's air duct cleaning standards and, if your ducts are constructed of fiberglass duct board or insulated with fiberglass duct liner, with the North American Insulation Manufacturers Association's (NAIMA) recommendations.
Do your homework before allowing chemicals or sealants to be applied to your ductwork. Questions remain about the safety, effectiveness and overall desirability of sealants, and chemicals can sometimes cause adverse reactions. Visit the EPA’s air duct page for information about sealants and chemicals.
✓ Reviewed and approved by Repair.com expert Michael & Son Services.
B. Leslie Baird
Barbara has an A.S. degree in engineering technology and a certificate in mechanics. She spent many years in the electro-mechanical trades. She's also worked as an electrician and performed other construction-related work.