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Find Out How Your AC System Is Making Your Allergies Worse

Many of us get endless sneezes, itchy, runny noses and watery eyes because of allergies.

According to the Asthma and Allergy Foundation of America (AAFA), more than 50 million Americans have experienced various types of allergies each year and allergies are the sixth leading cause of chronic illness in the U.S.

There is an almost endless list of things that people can be allergic to, and there have been a lot of Google searches for “Am I allergic to my air conditioner/furnace?”

We’ve got the answer right here!

You can’t be allergic to the equipment, however, it is possible that it’s not doing you any favors either.

Your allergies are getting triggered by all of the things that are carried and stirred up by your heating ventilation and air conditioning systems (HVAC). Dirt, dust, pet dander, pollen, and mold all migrate into your home and eventually get spread into every room through the duct system.

What’s in Your Home AC System that Makes You Sneezy and Itchy?

The air in your home will pass through the HVAC system about five to seven times per day, which gives you a lot of chances to be breathing in and coming into contact with nasty gunk. There are a few airborne allergens, viruses and bacteria that might be living in or circulating in your system. Those contaminants could be causing your coughing, sneezing, watery eyes, congestion, tiredness, fever and digestive issues.

Signs your AC system is the culprit for making your allergies worse:

  • You sneeze, get itchy eyes, itchy or stuffy nose and other allergy symptoms worsen when air conditioner is on.
  • When you some spend time away from your home your symptoms improve.

So, what is in your air conditioner that is causing these super fun symptoms?

Below is a list of allergens and air contaminants that can be found in AC and heating systems.


While bees for crazy for the stuff, people with allergies try to avoid it like the plague. Pollen can come into your home from open windows and doors. You, your family members and pets can be tracking it in on their feet and clothing.

The little pollen particles can transfer from you to carpeting and furniture where it can get trapped, especially during allergy season when pollen counts are the highest – spring and summer.

Dust Mites

I don’t know if you have seen what dust mites look like under a microscope but if you haven’t yet, don’t. They aren’t cute. Unless, you’re into tiny spider-crab things, no judgement. But regardless if you find them adorable or not, they definitely aren’t something you want an abundance of in your home.

The good news is they don’t bite, live on humans or spread disease, but they can cause a nasty allergy flare up. Dust mites like to hang out in the same cozy, comfy areas of your home that you do. You can find dust mites in furniture, pillows, mattresses and box springs, blankets, curtains, carpeting, and other fabric items in the room.

Pet Dander

If you have a pet, you know how much they shed. I mean good luck wearing black, am I right?

As much hair as there is all over your house from your furry friend, there is also dander which is made up of proteins that many people are allergic to.

According to the AFAA, three out of 10 people in the U.S. are allergic to dander, saliva and urine from common household pets.

Mold and Mildew

Many types of mold and mildew can get people’s allergies flaring up like nothing else. They release toxins that may cause an allergic reaction and even disease.

Mold is a fungus that thrives in humid and wet conditions, and we all associate that lovely mildew smell with moisture. Who doesn’t love the smell of towels that accidentally sit in the washing machine too long?

High humidity and water leaks can cause mold and mildew growth.

These next few aren’t typical allergens, but they will make the air quality in your home worse. You don’t want to be breathing these in either.

Bacteria and Viruses

If bacteria and viruses have been picked up by your system, they are circulating in your home. Duct systems can be the host of bacteria and viruses and if left unchecked can mean your whole family can be inexplicably ill any time of year.

Some airborne bacteria and viruses that could be living in your system include influenza, measles, chicken pox, legionella and staphylococcus.


According to the Environmental Protection Agency, indoor air is two to five times more polluted than indoor air. Car emissions, smog, tobacco smoke, and a whole list of other nasty things can get into your AC system and circulate all over your home. Unfortunately, your house isn’t impervious to pollution.

Volatile Organic Compounds and Chemicals (VOCs)  

VOCS are gases emitted by a good variety of household items. Cleaning supplies, paint, pesticides, gasoline, some air fresheners and candles, and cigarette smoke are all examples of products that can emit VOCs into your home.

How to Optimize Your Home Air Conditioner to Keep Allergies at Bay

So, now we know why your AC system could be flaring up your allergies, but how do you fix it?

Excellent question.

If you make some subtle changes to your system, it can greatly reduce the number of allergens and air pollution circling around in your home.

Having a well maintained HVAC system and the right equipment for the job can effectively reduce allergies.

Good Air Filters

Normal air filters are designed to protect the HVAC and not you. Not all filters on the market will keep out allergens, some only keep large items from damaging the system’s equipment.

Filtering out all the gunk is the best way to keep it from getting to you. MERV ratings will keep you educated on what you’re buying at the local store. They will tell you the minimum amount of what they can filter out.

PLEATED FILTERS: These filters are typically made of polyester or cotton that are folded like an accordion called pleating. These are the most common filters that are used in residential homes and are easy to find. As long as you purchase one with a high enough MERV rating, they are effective at removing all the allergy ick from your system.

ELECTROSTATIC FILTERS: These filters are usually made using cotton or paper fibers that are self-charging, which attracts air impurities to it. These filters draw dirt, dust and other allergens like dust mites to them and trap it. They help keep the air in your home free from common allergens.

HIGH-EFFICIENCY PARTICULATE AIR OR HEPA FILTERS: These filters are the best of the best. They were created during WWII to prevent radioactive particles from escaping laboratories. Compared to radioactive particles, pet dander would be a cakewalk, right?

Now a lot of brands throw around the term HEPA, but some aren’t true HEPA filters. They must be able to capture at least 90 percent of all particles 0.3 microns or larger in diameter. Be sure you are buying a filter that meets true HEPA standards.

If you’d like to learn more about MERV ratings and different types of filters we have a huge and informative guide you can check out – “The Last AC Filter Guide You’ll Ever Need”


Good quality air filters are an excellent place to start, but there are more steps you can take to make your system as allergen-free as possible.

CLEANING OUT DUCTS – Years of pollen, dust, and mold spores can be hanging out all up in the ducts of your system. Certified HVAC technicians can easily clean all that filth that has been collected. The National Air Duct Cleaners Association suggests cleaning your ducts every three to five years.

REMOVING DEBRIS AROUND UNIT– By cleaning away all the dirt, debris and plants from the area around your outdoor unit, you will stop it from sucking up outside allergens and circulating them around your home.

CLEAN OR CHANGE OUT FILTERS OFTEN – You might have bought a fancy filter, but if it’s clogged up with all those nasty allergens, dirt and other stuff that gets caught, it can’t do its job anymore. You should check your filters monthly to be sure they aren’t completely full.

Not only will cleaning out filters help to keep your allergies under control, but it will also ensure that your system will run efficiently.

CHECK FOR MOLD- Mold can not only make your allergies act up, but it can also make you ill. Mold loves moisture and humidity, and there are a couple places where it likes to collect in your system. Either you or a technician should check the condensate drip pan/drain, air handler, evaporator coils and air ducts.

If you spot a small amount you can easily handle it on your own but if you see a large amount of it, it’s best to leave it to the pros.

Other Ways to Improve Allergies in the Home

Now we know how to keep our home air conditioning systems clean and how to reduce allergens, but is there anything else I can do to help keep my allergies under control?

You’re darn-tootin’ there is!

Here are some additional tips for keeping your itchy, sneezy, sniffles at a minimum:

Clean Often

By keeping your home spic and span, you’re reducing the amount of allergens in your home.

Dust properly, shocking but there is a correct way to do it. This is the way Martha Stewart recommends.

If you’re unsure whether or not you are cleaning your home effectively or often enough, here’s a link to a weekly cleaning list from Good Housekeeping magazine. You can compare your list with theirs.

Control Humidity

It is important to keep humidity levels in the sweet spot. If your home gets too dry, your nasal passages and throat can become dry, making your allergy symptoms worse.  If your home gets too humid, it becomes the perfect place for dust mites to mate, and for mold and mildew to grow.

The ideal humidity for your health and comfort is between 40 and 50 percent.

Add an Air Purifier

Air purifiers are a perfect addition to make sure your air is the cleanest it can be. There are a lot of options on the market. Be sure to do research before purchasing, you want to know that it will filter out all the contaminants you need it to.

Air Out Your Home

Opening windows gets some new air in circulation. A little fresh air never hurt anyone, even those with allergies. Just, maybe, don’t do this on days with a lot of wind, or during peak allergy season.  Wait for a day with good air quality.

Wash Bedding and Linens in Hot Water

Your skin cells, pollen, pet hair/dander, dust mites and other really wonderful things all collect in your bed. Washing your sheets in hot water weekly will eliminate the build-up of allergens.

Wash Pets Weekly

Washing your fur baby often will cut down on how many allergens they may be tracking into your home and it will also wash away some their dander.


I don’t know about you, but I sure learned a lot about allergies and AC systems today. A quick summary couldn’t hurt, right?

  1. You can’t be allergic to HVAC equipment but you are allergic to the allergens inside the ducts that circulate air in your home.
  2. If your allergy sniffle sneezes get worse when the heat or AC comes on or if your symptoms improve when you’re away from your house, it might be the allergens in your heating and cooling system that are to blame for your worsened symptoms.
  3. Using a filter designed to filter out allergens and thorough maintenance can help to reduce allergies.
  4. MERV ratings are used to tell consumers the minimum of what to expect filters to eliminate from the air flow. Not all “HEPA” filters are real HEPA filters.
  5. Keeping your home, sheets, and pets clean can reduce your exposure to allergens. Controlling humidity, adding a purifier and airing out your home on good air quality days are other ways to keep the air in your home the healthiest to breathe.

Now, with all that said. No guide is perfect, and it is possible you’re left with some lingering questions because everyone has different needs when it comes to HVAC systems… Which is all good, because ISC Sales has some very knowledgeable people that are on standby to help you.

Call ISC Sales today at 972.694.4291 to get a free quote or to ask about our lineup of industrial equipment. You can also request a quote online, HERE.

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