Should You Clean Your Air Ducts? Separating Fact and Fiction


Your air ducts are an important component of the overall indoor air quality within your home. However, when dust and other pollutants start to build up, it can become a serious health issue. This may leave you wondering if you should have your air ducts cleaned?

Cleaning air ducts is unnecessary and provides no measurable benefits for most people according to the EPA. Exceptions include instances of substantial visible mold growth, rodent or insect infestations, and substantial buildup of dirt and debris inside the air ducts. The EPA findings concluded that most instances of poor indoor air quality had little to do with the homes air ducts.

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According to HomeAdvisor, Most households will only need to have the air ducts cleaned every 5 to 7 years. Some households may never need to have the air ducts professionally cleaned.

Throughout this article, we will dive deep into the facts and fiction concerning the cleaning of air ducts and what you can do to avoid it. You’ll also learn plenty of other information, including:

  • Details about why and when you should clean the air ducts in your home
  • Potential risks involved with improper cleaning techniques
  • Measures to avoid cleaning of air ducts
  • How proper maintenance can prevent the need for air duct cleaning
  • Answers to all of the most commonly asked questions

Facts about Mold Spores, Dust, and Other Airborne Pollutants

Dust, dirt, mold spores and other airborne pollutants are everywhere. There is no avoiding them. During certain times of the year, airborne pollutant levels will be higher than others.

These airborne pollutants make their way into our homes through opening and closing or doors, windows, and other areas of ventilation.

Older houses are particularly well ventilated due to low levels of insulation. This can actually be beneficial to better indoor air quality due to their ability to circulate air more freely.

Newer houses are more susceptible to experiencing poor indoor air quality because these houses are airtight and better insulated. While modern homes are more energy-efficient, they prevent the necessary free flow of air within the house.

Airborne dust, dirt, and mold spores settle on the surfaces inside your home. Particles that remain airborne get drawn into the duct system through the air return. Without a proper air filter, these particles will settle onto the air duct walls and on the internal coils of the heating and cooling system.

There are reasons the EPA and other organizations claim the cleaning air ducts are a waste of money. These include:

  • Most companies provide an incomplete job. Companies who advertise air duct cleaning for prices of $99 or less, often are not doing a complete job. Most of what they do, you can do yourself for free.
  • Cleaning of air ducts should be the final piece of a more complete cleaning picture that includes a routine household cleaning schedule, proper routine air filter maintenance, and annual service of your HVAC system. Cleaning air ducts without these measures is useless.
  • Studies have shown that indoor air quality is rarely positively affected after air ducts have been cleaned. Any positive improvements in indoor air quality wane in a manner of days returning the pre-cleaned levels.

Case Studies on Air Duct Cleaning

It should be noted that in these case studies, the sample sizes were relatively small and only air duct cleaning was performed. Other factors such as location. household cleanliness, air filter type, HVAC condition, etc were not equal and can easily skew results.

For example, the study performed by EPA researchers measured dust levels and HVAC system efficiency in test homes during a one-week period during the cooling season. They concluded from this very small, semi-controlled study that air duct cleaning did not significantly improve dust levels or system performance.

The EPA concluded:

“Duct cleaning has never been shown to actually prevent health problems. Neither do studies conclusively demonstrate that particle (e.g. dust) levels in homes increase because of dirty air ducts. This is because much of the dirt in air ducts adheres to duct surfaces and does not necessarily enter the living space. . . . 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.” – United States Environmental Protection Agency

Another study in the 1990s by The Canada Mortgage and Housing Corporation (CMHC) investigated whether: duct cleaning made indoor air healthier; and does it reduce energy costs by improving airflow.

The testing was performed in 33 homes in Montreal before and after duct cleaning was performed. They concluded:

“Ideally, the inside surface will be shiny and bright after cleaning. Duct cleaning may be justifiable to you personally for that very reason: you may not want to have your house air circulated through a duct passage that is not as clean as the rest of the house. However, duct cleaning will not usually change the quality of the air you breathe, nor will it significantly affect airflows or heating costs.” – The Canada Mortgage and Housing Corporation

These studies leave a lot to be desired and could easily be considered to be scientifically flawed at best as they lack several measuring factors critical to the long term success or failure of air duct cleaning.

When Should You Get Your Air Ducts Cleaned?

I agree with the EPAs assessment that cleaning your air ducts should be reserved for severe cases of visible mold, rodent and insect infestations, and where there is a significant buildup of dirt and debris. However, this is not the whole recommendation and should be a part of a broad scope of action.

Routine Household Cleaning Schedule

The decision to clean your air ducts should be the last course of action for most people. Maintaining routine household cleanliness, for most people, should be their first course of action. Most people think their homes are clean but are horrified when they discover just how dirty certain areas really are.

For example, window treatments including curtains and blinds, cloth furniture surfaces, spaces under and behind furniture, ceiling fans, and along baseboard trim are areas that rarely get cleaned and can hold large amounts of dust and dirt, including millions of mold spores and other contaminants.

Our lives are very busy and, for most families, routine household cleaning just doesn’t happen as often as it should. It’s more like “do a little here, do a little there” as time allows between both parents working, soccer games, and other family activities.

Change Your Air Filters Regularly

Air filters are the air duct’s first line of defense to staying clean. As air filters become clogged and fail, airborne pollutants bypass the air filter and settle inside your air ducts and the internal coils inside the HVAC system.

Changing your air filters every 30 to 90 days (depending on the air filter type) is important. Air filters help collect airborne contaminants before they enter the air ducts. Fiberglass air filters need to be replaced every 30 days while pleated air filters can last 30-90 days. Pleated air filters collect more airborne contaminants depending on their rating.

Also, be sure not to run your HVAC system without an air filter. If no air filter is present, the air contaminants settle on the inner walls of the air ducts. Over time, this buildup can become a mini-ecosystems for other mold and organisms to thrive. See our article Should You Put Filters in Your Return Vents?

Service Your HVAC Annually

Most people do not even realize that they should be servicing their HVAC system annually. The internal coils in your HVAC system can be breeding grounds for mold.

HVAC systems produce condensation during the heat exchange process. A poorly maintained system can have layers of dust, dirt, and mold on the internal coils. As air passes over the coils, these particles are picked up and distributed through your air ducts.

Having your HVAC system properly serviced annually, can help significantly reduce the need for cleaning your air ducts.

Clean Air Ducts Reduce the Electricity Bill

Many HVAC workers claim that cleaning your air ducts will save you money. You might think they’re just pitching a sale, but they’re actually onto something. As NADCA points out, your air conditioning and heating bill can soar through the roof from clogged, dirty air ducts. But why is this?

Air ducts circulate air through your house, working very similarly to the way that blood moves through our bodies. When the area that air can move through becomes smaller and smaller from a dust clog, it starts to work extra hard to produce the same effect. You’ll end up paying twice as much as you should without getting a good result!

Your Air Ducts Will Last Longer

Much like almost everything else around your home, cleanliness can increase the longevity of your air ducts. They’ll warp, crack, and eventually break if they’re never cleaned. By hiring a professional to come out and take care of the job for you, you’ll be able to save even more money in the long run. Replacing air ducts isn’t cheap!

If you’re set on cleaning your own air ducts (although it’s highly recommended to hire a pro), check out this video.

It Makes the Air Easier to Breathe

Who’d have thought that having central air circulation could cause breathing problems? It’d seem like air ducts would be the best thing for people who suffer from lung issues (which it is), but dirty vents can be even worse than stagnant air. As long as you have them cleaned regularly, it’ll keep the air feeling great.

Your House Can Heat and Cool Quicker

Much like the blood circulation example from easier, the temperature of the air moving through the air ducts is restricted when the ducts are dirty. It’ll heat and cool the dust before it ever gets to the living room. Fortunately, clean air ducts will allow your home to have its temperature adjusted as soon as you adjust the thermostat (assuming everything else is working properly).

There are many more reasons to have your air ducts cleaned, such as reduced chances of mold growth, new home/renovation debris removal, and routine inspections for dents, rust, and other issues.

Some homeowners have heard scary stories about having their air ducts cleaned, but it’s not nearly as bad as it sounds. In fact, there are far more benefits than risks. For those of you who are curious about what could possibly go wrong, proceed to the next section.

Are There Any Risks?

Although it’s typically performed by a professional, cleaning air ducts can have a few associated risks. None of them are as bad as the risks of not cleaning them, but it’s worth knowing what you’re getting yourself into.

Here’s a handful of issues that come with cleaning air ducts:

  • According to Bobvila, cleaning non-metal air ducts could cause important components to become disconnected. You’ll have to take note of all of these connections prior to starting the job. If you’re worried about a professional missing them, ask to walk through the whole process as they go through it.
  • It’s inevitable that cleaning air ducts will cause dust to fly around a bit. Since dust is so lightweight, it’s nearly impossible to get every last particle. Some of the dust will move around your house for a couple of hours until the air ducts do their job to remove it. The amount of dust is minuscule, though.
  • If you DIY the job, you might end up causing irreparable damage. The best reason to hire a professional is that they’re responsible for fixing anything that they break. By doing it yourself, you’re the only one left to blame. You might even end up spending more money on repairs than if you simply hired someone else.

The potential risks aren’t too frightening, but everyone should know both sides of the process. Now that you can compare the pros, cons, and various reasons that you should clean your air ducts, you’ll be able to make an educated decision.

FAQ

If you’re still curious about some of the fine print involved with air duct cleaning, then you can review the most frequently asked questions below.

  1. How do I keep my air ducts from getting dirty? The best way to do this is to install brand-new filters and clean them often. You’ll have to follow manufacturer instructions to get the correct size and decide how often they need to be replaced.
  2. How much does it cost to have my air ducts cleaned? Angie’s List shows that the average cleaning costs between $300 to $500, but those rates could vary depending on where you live, the size of your home, and the number of HVAC systems you have in your home. Data from HomeAdvisor states that the 2020 average cost of air duct cleaning is $368, or between $268 and $483. Larger homes, or those with more ducts or contamination, might pay as much as $700.
  3. Can I clean my own air ducts? You might think that it’s a simple job, but in most cases, hiring a professional will save you time, money, and stress. Cleaning air ducts is challenging, so it’s best to leave it to the experts.

Conclusion

If you haven’t guessed it by now, you should have your air ducts cleaned routinely. Mold odors, dust particles in the air, loud ventilation, high electricity bills, and reduced temperature efficiency can all be obvious signs that it’s time to clean the air ducts.

Here’s a quick breakdown of the post:

  • Dirty, dusty air ducts can cause breathing issues and fire hazards.
  • A sky-high electricity bill can often be fixed by cleaning your air ducts.
  • Non-metal ducts should be carefully inspected for loose connections.
  • Using a filter will keep your air ducts clean longer.

Sources

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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