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How often is it recommended to have your air ducts and your dryer ducts cleaned? I know what the AC/Heating people recommend but I want to know what is really recommended, if different.
We had our air ducts cleaned in our old house after we had some work done to the house. The duct guy said that you really only need to have them cleaned once unless you do some work where you are kicking up a lot of dust like sanding drywall. It did make a huge difference in the amount of dust in the air despite what that posted article said. The duct cleaning guy said that if you change your furnace filter once/month as recommended after cleaning your ducts you shouldn't need to do them again.
Location: Sometimes Maryland, sometimes NoVA. Depends on the day of the week
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You should clean your dryer duct annually. But you don't need a pro to do it. You can buy a brush that attaches to a drill to do it, or we just do it ourselves with the vacuum and a stick to knock down the lint.
Here (http://www.cpsc.gov/CPSCPUB/PUBS/5022.html - broken link) is the CPSC recommendation. But they tend to be conservative in DIY stuff, so it recommends professionals.
Depends upon the duct system and the home residents. Often only needed for parts of systems with floor ducts that can collect dirt and dust when not in use and get debris from pets and children. My experience is that every five to ten years is adequate for most ducts.
I apologize in advance for the length of this post, but while duct cleaning isn't rocket science there are several things that you should know!
Frequency! - Once thorough cleaning has been done, it really depends on what type of filtration you have, the amount of traffic thru your home (kids, pets, etc.) the environment around you (farms, busy road, gravel drive, etc.) and how clean you keep your home to determine how often your system will need to be cleaned again.
Filtration - Filter efficiency varies! Some of today's best whole house filter systems will remove up to 99.98% of the contaminants, but those most commonly used are fiberglass at 7 to 10% and 1" pleated media at up to 30% efficiency. These types of filters should be checked monthly and replaced when dirty. Those using 2" to 6" pleated media (30 to 60% efficiency) should check them every 6 months or so. Washable filters and electronic air cleaners with metal cells should also be cleaned monthly.
Please note that you should always check with your heating contractor before installing a more efficient filter than your system currently uses. Some of the higher efficiency filters such as 3M can restrict air flow enough to cause your heat exchanger to overheat and crack!
ASTHMA? - For those with respiratory problems, I recommend thorough cleaning to be followed by the installation of a high efficiency filter. The return side will continue to get dirty, but the high efficiency filter will continue to clean the air every second of every day helping your loved ones breathe easier!
Carpet Cleaning - I highly recommend that all carpets be thoroughly cleaned (either professionally or with your own vacuum) immediately BEFORE or AFTER duct cleaning is done to prevent dirt trapped in the carpet from being released into the air (during your daily activities) and recontaminating the system when it is in operation.
References - While family, friends, and co-workers are often a good source for referrals, it is always a good idea to contact SEVERAL of your local heating & air conditioning companies or fire/water/disaster restoration services to see who they recommend. The best companies are those who specialize in air duct cleaning. Others such as department stores and carpet cleaners often rely on specials or name recognition rather than quality to get your call and despite what you may read certification isn't a guarantee for quality!
Time! - Thorough cleaning takes time and patience. One or two experienced techs can thoroughly clean a smaller home in 3 to 4 hours. A 2 story (single furnace) home should take them 4 to 6 hours and anything larger or those with multiple systems will take longer and/or require additional crews to finish in one day. I also highly recommend staying away from any company that schedules more than two jobs per truck per 8 hour day.
Cleaning - Negative pressure (vacuum) should be used in conjunction with some form of agitation to remove the dirt from your system. The vacuum is usually attached to the supply and return side of the furnace with each side being isolated and cleaned separately. This prevents the vacuum from pulling additional dirt thru the coil or heat exchanger. The vent covers (when removable) are removed and cleaned and the pneumatic cleaning tools on small flexible rods inserted into these openings to clean the smaller branch ducts. The main ducts are then cleaned in a similar manner.
Cleaning Your System - Not Just The Ducts! At a minimum, cleaning should include all branch supply (hot air) and return (cold air) branch ducts and all main supply and return ducts.The most reputable companies will also take the time to (when applicable) remove, disassemble and clean your system's blower, clean the indoor coil and its drain pan, clean the secondary and/or primary heat exchanger, as well as your electronic air cleaner, washable filter, humidifier, etc. Failing to clean these critical components leaves dirt inside your system that will be distributed throughout your home when your system is in operation!
Equipment - Generally the best companies will have a truck mounted vacuum (producing a minimum of 5000cfm), pneumatic cleaning tools (whips, sweeps, rotary brushes) and they will be able to show you how clean your system is when they are done. Those that do the most thorough job clean with live video and welcome their customers to watch. This also eliminates any need for their techs to guess when each duct is thoroughly clean!
Indoor Coil - If you have a heat pump or whole house air conditioner, the duct cleaner should also protect the coil to prevent their cleaning tools and debris (marbles, coins, small toys, etc.) inside the ducts from damaging it during cleaning.
Soot Sealing - Thorough cleaning means just that and there should never be any dirt left inside that needs to be sealed in!
Sanitizing - Mold requires 4 basic things to survive. Three, including darkness, an appropriate temperature and a food source (dust) are found in every system, but the 4th (moisture) is rarely found and only results from a problem that must be corrected first. This moisture can come from several correctable problems including damp basements, water leaks, humidifiers working improperly or set too high, an a/c coil that is dirty or improperly sized or installed, etc. and until the moisture problem is corrected daily mold will continue to grow.
Bargain Prices! - Beware of "whole house specials." These often include fine print that allows them to jack the price up considerably once they are in your home and make sure that whoever you use will give you a guaranteed final price in writing before they start work. If you ever fall victim to bait and switch ads or high pressure sales tactics, contact your state attorney general and file a complaint!
Last edited by Options; 02-17-2008 at 11:57 AM..
Reason: typo
Duct cleaning can actually result in air that is DIRTIERafter cleaning. While although there are legitimate reasons to clean one’s ducts, in general, the more you clean your duct work, the dirtier your indoor air will be.
[Mod Cut]
Last edited by ontheroad; 02-17-2008 at 01:52 PM..
Reason: Signatures of this kind are a ToS violation.
golfgal= securing the system electronically and blocking vents (for instance, with magnetic covers on grills or duct tape/drycleaning bags) during a construction phase would prevent it from ever entering the system. Stick with external blowers as needed, clean the area thoroughly when you're done sealing drywall, it should be a non issue.
cdelena= not just the number & nature of inhabitants (heavy shedding animals), but sq footage the system has to serve, how often its used, how much the system is strained by people who don't dust/vacuum enough, and outdoor air quality factors (high pollen areas for instance). I think instead of a mathematical schedule, makes more sense to observe what gets accumulated in how much time to establish a schedule specific to as-is where you are.
options= thanks so much, very informative. I can't tell you how many people I've met who have no idea where their furnace filter is, or that a grill exists on the back of their fridge that needs periodic vacuuming. Either its someone elses job in a service contract, or they're too intimidated by the 'mysterious system' to venture into the basement. LOL
jenn= my response to cdlena; you could start by seeing how frequently your intake filter is getting dirty, open up a vent and do the white glove check, monitor over time. You could also invest in unit air cleaners to take some of the burden off your system which has a different primary function.
cdelena's suggested schedule is likely on the money for the average home owner.
***dryer duct cleaning is pretty easy if you've got short discharge hoses, but should be done more frequently. Go with your homeowners insurance recommended cleaning schedule because it's a fire hazard if you let it accumulate. Commercial laudramats might clean them twice daily, but your usage would be significantly less.
The studies referred to in the above "discussion" were done many years ago in uncontrolled environments and with what would now be considered outdated methods and equipment. The results of a more recent and far more scientific study were done and published by the EPA in their 1997 Spring/Summer edition of "Inside IAQ" and can be found at:
This field study was limited to non-porous bare metal ducts and demonstrated that mechanical air duct cleaning can be an effective source-management tool reducing particulates, odors and VOC emissions thru the removal of contaminants within the system. It also demonstrated an increase in system efficiency and suggested that air duct cleaning has a positive impact on system performance.
For those who have no desire to read the entire article, the Field Study on Residential Air Duct Cleaning begins on page 6 and describes the methods used and work performed along with a summary of the results.
yeah, Options, I had a sneaking suspicion (call me kooky) that leaving dust remaining where it is as a banquet for mites and blowing the ensuing mite excrement throughout the house wasn't the ideal solution.
Added bonus with this voc stuff. I'll know to avoid fiberglass ducts in houses now. Thanks for the update.
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Air Duct Cleaning
