Do you wonder why your house gets dusty so fast?


Do you have something like this in your attic?

Do you feel like your house is always dusty, in spite of how much you vacuum and clean? Have you tried all the tricks – HEPA vacuum cleaners, air cleaners, taking your shoes off before coming in the house, washing the dog…. all to no avail?

Chances are good that you’re being plagued by a leaky duct and air handling system.

When you have leaks in your ducts (virtually all duct are leaky) dust from the attic gets sucked into the ducts and distributed throughout the house. Even if you have an excellent filtration system on your air handler, the dust can be sucked in from places that don’t get filtered, and blown into your home, usually leaving fine gray dust everywhere.

Before you call in a heating/cooling (HVAC) contractor, there are a few steps that you can take yourself.

Warning: working in an attic can be dangerous. Many attics don’t have proper floors. Numerous people have taken bad steps and fallen through the ceiling, often resulting in serious injury or death.

Assuming you are comfortable working in the attic and can safely access the duct work and air handling system, here are some things to check:

  1. Ensure that the air filter port is sealed air-tight.
    At least  10% of the systems I see look like the one in this picture. The air filter port is open and an over-sized filter is sticking out the side. Not only does this rob you of 20%-50% of your system’s efficiency(!) and cause the air to get extremely dry in the winter, but it sucks nasty, dusty attic air into the system where it is blown throughout the house. Fix this simple problem  (get the right sized filter and tape over the port) and you will see immediate energy savings and probably a much less dusty home.
  2. the duct "boot" has a big gap

    Check your air registers around your house
    Your home’s air registers should mostly be clean. If some are much dustier than others, this is a sign of leaks near that particular register. Sometimes it will be a leaky duct leading to it, other times it may be the register itself is poorly attached to the ceiling, providing a gap right into the attic. I’m always suspicious when I see a really dusty register.

  3. On a cold and windy day, turn off your forced air system (air conditioner, heat pump or furnace) and see if you can feel a cold breeze coming from any of the air registers in the house. The duct system is supposed to be completely sealed, so you should never feel really cold air blowing in. You might feel cool air drifting in due to the ducts being cold, which causes the cool air to “drop” out of the ducts. But if you can correlate cold air blowing in with wind outside, you’re sure to have leaks. The more of a breeze you feel, the closer you are to the leak.
  4. Poorly attached duct

    Look around the attic to see if any ducts are visibly detached or “askew”, particularly at registers and ducts that failed test #3 above.
    These can be hard to find, but sometimes it’s pretty obvious. All the ducts should be nearly and strongly attached at both ends – where it leaves the main trunk lines and where it feeds the ceiling registers or air returns.
    I’ve seen cases where the ducts have totally fallen off and are just lying on in the insulation.
    Note: special tools and adhesives are used  to connect ducts in a permanent fashion. Do not attempt to repair these problems with “duct tape”! – this tape will fail and you’ll be left with leaky ducts again. Instead, industrial strength zip-ties and tensioning tools are used along with a sealant called “mastic.”

  5. Sometimes problems are hidden in walls
    You might not be able to find any problems in the attic but the problem could still lie in your ducts. Many duct systems run through walls and hidden cavities in your home. It is even common  practice to use naked wall cavities without ducts! Contractors will just pick a wall, ceiling or floor cavity and run air through it. This horrible practice really shouldn’t be permitted because it causes so many problems.
    This type of problem you probably can’t find yourself. A trained infrared thermographer (often an energy auditor or building scientist) may be able to locate the problem, but sometimes it can be very difficult.
  6. Beware of Vermiculite
    Some older homes have Vermiculite insulation in the attic. These homes should not be tested using a blower door or duct blaster and you should not poke around in this material because it may contain asbestos. Not all Vermiculite contains asbestos, but this is definitely a case of “better safe than sorry.”

I started this post saying that you shouldn’t call in your HVAC contractor and I’ll finish it by saying the same thing. Many HVAC contractors are not trained to find these leaks. Think about it – who created these leaky ducts in the first place?

As a building science / energy consultant, I’m biased because I’m an independent consultant, and I recommend that you use someone who is also independent to diagnose your issues. They might fix them as well or they recommend a high-quality HVAC contractor whom they know to do good work. They will also have special equipment like a “blower door” and a “duct blaster” that allows them to quantify the leakiness of your ducts much more quickly and accurately than someone without these tools. In fact, without at least a blower door, it will be very difficult to even find many duct leaks.

Fixing duct leaks can help make your house much less dusty and it has the side effect of making it more comfortable and energy efficient. This is one of those things that you’ll wish you had done years ago because it can make your house more enjoyable to live in every day of the year.

Follow-ups:

“Why does house get dusty when heat on and not with ac on?”

Occasionally, weird things happen. If you’ve gotten this far, you know that the dust is usually sucked in and distributed by the duct system. If that’s so, then how does the above situation occur?

There one possibility that comes to mind – moisture.

During the summer, the cold coils in the air conditioner are covered with water – this is the summer moisture getting drawn out of the air. When the dusty air moves through the coils, much of this dust could be trapped by that water. This would lead to much less dust when the air conditioner runs than when the heat is on.

“Does an energy audit show why there is so much dust in the house?”

Someone else asked this question. The answer is “maybe.”

If the energy audit is a comprehensive review of your home, done by a competent technician, then yes, the audit should be able to show why your home is dusty. To make sure, you should tell your auditor that you’re having a dust problem and you’d like some help finding out why. If they look confused and don’t suggest issues like the ones mentioned in this post, you should probably find a different auditor!

“Why is the air so dry in the winter?”

What does dry air have to do with a dusty house? Possibly everything!

If your duct system is sucking dusty air in from the attic, it will also suck in the very cold, dry air from the attic. When that dry air enters your house, it sucks up the moisture from your home like sponge, resulting in very dry air. That’s why an uncomfortably dry home in winter is a giveaway that the home is very leaky.

Keep in mind that the dry outside air could be coming from anywhere. If you have leaky windows and doors and a drafty house, it’s also going to be uncomfortably dry. That said, nothing dries out a house faster in winter than a leaky duct system that’s sucking in cold, dry outdoor air.

Advertisements

61 thoughts on “Do you wonder why your house gets dusty so fast?

  1. I am getting what appears to be white type lint that gets in my eyes and face and is giving me headaches.I had a new furnace put in 10 years ago through a government assistant program that did a shoddy job. I am worried. Can I get cancer from this? They would not address this at the time and I had to pay over three hundred dollars to redo all the ductwork,as it all fell apart.I wonder if I am breathing in insulation?

    • I certainly can’t comment on your specific cancer risk. If it’s that bad, you need to have the material tested. In general however, no modern insulation materials have been shown to have serious health consequences. Yes, some are irritants – for example, handling fiberglass leads to extremely itchy skin. Loose fill insulation, the type that’s blown into attics such as fiberglass and cellulose (shredded newspaper) often are very dusty and if the ductwork isn’t well sealed, can be sucked into the ducts and blown around the house which will lead to a dusty house.
      If you have ductwork in the attic or the main system is in the attic, this would have to be carefully examined for leaks and sealed up. This requires someone with a real eye for detail, but anybody can examine it if they can safely navigate the attic. Look for openings around the blower – seams that aren’t sealed air-tight. Then examine how the ducts are attached and run to the vents. Seams should be sealed and/or taped with special materials. Any gaps will be prone to sucking in dust. It’s unpleasant and time consuming work, but your health comes first.

    • I just had the same done in 2016. My entire home is infected. We had to close off the air condition system due to the debris falling from the vents. It’s a total mess. You might want to check your health. We are having a lot of health issues. We have had many Infections in just over a year. The entire home has been infected. I can’t clean any more I get so sick when I try to clean. I can’t get any help from any agencies. I’ve been looking into it for over a year now. There are regulations listed but no one to report them too. The energy program is running all on there own. All of these programs run on goverment money. There is no goverment agencies to report problems too. I wish I knew this before I had them come into my home. I have photos videos of all the damage. They were suppose to prep the attic before installing the insulation, They did not do it they blew the fiberglass insulation into the attic. It was falling all over the house including us and the animals. The fiberglass would cut into my skin then the bacteria would enter into my body . I am covered with sores. Every nook and cranny in my house had debris falling out of it. My walls now have mold growing on them. I have a brand new fridge that has begun to decay on the side where the fibers fell onto it. I have been living in hell. I can’t find a law firm willing to take it unless I pay them a lot of money.

  2. Our furniture is dusty within 2 to 3 days. We had a mold miser put on our unit we have a new heat pump and also had the electric static filter system put on. We do not have any duct work in our attic. What type of company would we hire to look at our duct work?

    • You can start by asking the company that installed your heat pump for a reference to a contractor that does duct testing and troubleshooting. Often this will be an energy auditor. Depending upon where you live, there may be several qualified contractors or none. But that’s a start.

  3. I have many of the problems described in this well-written piece…I just don’t know what my next steps should be. I change my filters once a month. There is visible dust in the air in the morning light in the living room. I have dust on the clothes and jewelry inside of my dresser drawers in my bedroom. After 4 days, I can easily write my name in the dust in both the living room and the bedroom. I can write my name in the other rooms’ dust after 8 days EXCEPT for the “guest house”, which shares a wall with the main house but has its own HVAC system. It does not get dusty for weeks and weeks even though I open and close the door on a regular basis. I had an Energy Audit by a company that does not sell or install HVAC equipment. They did not have solutions, although I was not convinced of their educational background. (I am a Mechanical Engineer…but have not practiced for a while). One last thing. In the summer, there is a cool space in the living room that I cannot pinpoint. Same in winter…a warm space. So…I’m pretty sure that faulty ductwork is the issue. Where do I go for help since my first Contractor was unable to find a solution? I live in the metro Phoenix, AZ area.

    • I’m pretty sure you nailed it. Since the area on a different HVAC system isn’t dusty, there’s a really good chance that you’ve got duct leakage that’s sucking in and blowing dirt all over your home. It’s shame the energy auditor you had in couldn’t determine the source/location of the leak.
      You’ve also noted the room that gets hot/cold. With a thermal camera, it would be really easy to see the source of that issue. It might be related to the dust problem or it could be just another section of duct that’s not sealed well.
      Are your ducts accessible? Do any run under the house or through other areas which could be dirty/dusty?
      When you change your filter every month, is it really dirty? Are you using higher MERV pleated air filters? I like using those with a MERV from 9-12. I get mine from Nordicpure – good quality at a much lower price than the big-box stores.

      Many home testing companies have a device called a “duct blaster” which is used to test for air leaks. I used to do diagnose this type of problem using a duct blaster and a theatrical smoke machine. You blow the smoke into the fan that supplies air to the duct blaster. Then, wherever there are duct leaks, you can see the smoke come out. This is great for ducts that you can see, like in basements and attics. But if the problems are hidden somewhere inside the house, it probably won’t help.
      Hope this helps you track down the problem. These can be really frustrating!

  4. I live in a double wide home I have dogs that are regularly bathed I have DIRT in my home. I have it on my dishes in cabinets its everywhere I can not keep it cleaned HELP

    • Sounds bad! Have someone check your ducts. They’re probably sucking in lots of dust and dirt from under the house.
      Temporarily, you can put filters over the vents where the air comes out for the AC / heater. You don’t want dense filters as that will impede airflow too much, but you can use the mesh filter that can be cut to size. This will also confirm that the dirt is coming from the vents because the filters will get dirty.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s