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Do Air Conditioners Improve Asthma Control?

Air conditioners are great for those hot summer days. They keep the air cool, refreshing, and comfortable. There’s also evidence they may help improve asthma control. That in mind, here’s all you need to know about air conditioning (A/C) and asthma.

Do A/C’s reduce airborne triggers?

According to many studies, the answer is yes. However, they only benefit asthmatics if their filters are properly maintained.

A 2011 study showed air conditioning reduces the impact of traffic pollution on children with asthma.1

Another 2011 study showed the benefits of central air conditioning on asthma. The article noted that 75% of U.S. households had “ducted forced air heat.” And 63% had “ducted central air conditioning.” The study showed that both of these heating and cooling systems are great for filtering out airborne allergens. Examples include dust mites, animal dander, pollen, and mold spores. They also work great for filtering non-allergic asthma triggers, such as smoke from wood fires, smoke from cigarettes, and various forms of air pollutants.2

How do I maintain an A/C unit?

Air conditioners are not effective if the filter is not replaced or maintained as recommended by the manufacturer. Heating and cooling specialists say they often find that filters are filthy. When this happens, they can become breeding grounds for air contaminants, such as mold spores. When this happens they can actually increase airborne contaminants. So, it’s essential that asthmatics properly maintain filters.2

The authors highly recommend whole house filtration systems. This is best accomplished with central heating and cooling systems as opposed to the kind you put in windows.2

When the filter is properly maintained or replaced, these units are very effective at minimizing airborne asthma triggers. So, they are effective at minimizing the risk for asthma symptoms.2

A/C’s also make it so you can keep doors and windows shut. This can also help to keep outdoor air pollutants (like pollen) outside.3

Do A/C’s create a better breathing environment?

The general consensus of experts is probably “Yes they do!” As noted above, they work great for filtering airborne asthma triggers. They are also great at reducing humidity.

The hotter the air the more water it holds. So, during the dog days of summer, the heat and humidity can trigger asthma symptoms. There are a variety of reasons for this.

Hot, sticky, air can feel thick and hard to inhale. This alone may trigger asthma in some. Another reason is that hot and humid air creates a breeding ground for some asthma triggers. Both mold spores and dust mites love this environment.

Mold can grow in this environment without you even being aware of it. And it releases mold spores into the air. They can trigger asthma. Dust mites can also rapidly multiply in this environment. Dust mites and their feces are easily aerosolized and inhaled. They may trigger asthma.

A/C’s work great for both cooling air and at the same time reducing indoor humidity. Most experts recommend that indoor humidity be kept between 30% and 50%. This is ideal for anyone living with chronic lung disease.4

So, are air conditioners good for asthma?

Air conditioners are nice. They keep the air cool and refreshing. They can reduce humidity and airborne triggers. The combination of these effects can improve asthma control. They can make breathing easier. But, they may also trigger asthma if not properly maintained.

So, the best A/C units will have “CERTIFIED asthma & allergy friendly® filters.” These are capable of filtering 98% of airborne allergens. Turn it on. Use the recirculate setting. You’ll feel more comfortable. Your lungs will be happier.4

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

  1. Zuraimi, et al., “Home air-conditioning, traffic exposure, and asthma and allergic symptoms among preschool chlidren,” Pediatric Allergy And Immunology, 2011, February,, accessed 7/21/19
  2. Sublett, James L, “Effects of air filters and air cleaners in allergic respiratory diseases: a review of the recent literature,” Current Allergy And Asthma Reports, 2011, October,, accessed 7/21/19
  3. "Control Indoor Allergens to Improve Indoor Air Quality," Asthma And Allergy Foundation of America,", accessed 7/23/19
  4. “Indoor Air Quality,” Asthma Initiative of Michigan,, accesed 7/21/19


  • BajaOklahoma
    6 months ago

    In additon to using the whole house AC, we also run a dehumidifier in the hotter months. It not only reduces the indoor humidity significantly (up to 30% less than the ourdoors), it helps the AC unit run less. We empty it twice a day, which means it is removing 2 gallons of water from the air daily.
    Though our air filters recommendations are to change them every 6 months, we have never been able to wait that long. We have four large dogs and three cats, all living in the house, so monthly works best. Sometimes I will notice that I am getting more sinus headaches or slight chest tightness, so we check the filters and replace them early. Whatever works.

  • Leon Lebowitz, RRT moderator
    6 months ago

    Hi BajaOklahoma and thanks for joining in the conversation here. We appreciate you sharing what works so well for you.
    I agree with you 100% about the air filters. Although some (do) recommend changing filters every 6 months, I also believe in changing them every month. This applies particularly if the A/C is running continuously day-after-day, week-after-week. Nothing will protect one’s air handler quite as well as 30-day filter changes.
    Keep up the good work!
    Leon (site moderator)

  • Sarah-artist
    6 months ago

    I am new to Asthma, or it is new to me. For several years I have been prone to getting nasty Bronchitis infections, and these have set off “acute breathing episodes” where my airways close up, often while asleep. My symptoms are still only in my bronchial tubes, my lungs are not involved, even when I had the episode of Flu & bronchitis that led to my diagnosis. Is this typical of Asthma? Seems my bronchials are damaged from past infections (sawdust, dirt and viral caused) but my lungs are normal. Per the article, I hope to soon have central air put in, because the window AC units I have all have black ick, in them and I am concerned that could be making my symptoms worse. However in winter I HAVE to use a Humidifier to keep my air breathable or I get congestion, sinus infections.

  • Leon Lebowitz, RRT moderator
    6 months ago

    Hi Sarah-artist and welcome. I see that my colleague, Lyn, has provided you with a good reference article that explains the asthma condition quite well.
    While you’re awaiting a central air conditioner installation, you may want to look into cleaning the air filters in your window units. Sometimes that ‘black icky’ material is just the normal buildup on the filters. Perhaps you could check that out (while wearing gloves and a mask, of course!) Please do check back and let us know how you’re doing. All the best, Leon (site moderator)

  • Lyn Harper, RRT moderator
    6 months ago

    HI Sarah-artisit – Thank you for joining the conversation. Let me assure you, what you’re experiencing with asthma is perfectly normal! The small airways narrow, making it hard for you to breath even though your lungs are performing normally. Very typical.
    Here’s an article that explains it well:
    Regards, Lyn (site moderator)

  • tonytoshiba
    6 months ago

    I have had severe asthma my whole life with an auto immune disease. Seems I was allergic to antibodies. Emphysema joined the party a few years ago.
    I exercise in the desert, mountains or large medical facilities during pollen season. Medical facilities have well filtered cool air and an abundance of stairs with landings.
    We have central HVAC at home. It helps my breathing to remain stable. I just upgraded my HEPA filter which rests next to where I sit.
    Yes, central HVAC helps. The HEPA filter cleans the air even further. We have a neighbor that smokes, a lot. My new filter steps up the filtration lpm when it senses contaminates, even from my nebulizer.

  • Leon Lebowitz, RRT moderator
    6 months ago

    Hi tony, and thanks for chiming in here. It sounds like you have your condition(s) (asthma and emphysema) under good control. The exercising will serve you very well and I like that you change the location (for your exercise routine) based on the weather and what’s available for you.
    Protecting yourself further, by using well-filtered air conditioning as well as a HEPA filter, is the way to go, too. Keep up the good work!
    Leon (site moderator)

  • Shellzoo
    6 months ago

    Wait! You mean my AC has a filter or is it just the furnace filter for central air? I use my ac pretty much all summer due to weed, grass and pollen allergies.

  • Leon Lebowitz, RRT moderator
    6 months ago

    Hi Shellzoo – thanks for posting this very good question. In my experience, so many (people, in general) do not know how to maintain HVAC systems whether they are simple window air conditioners, or central air conditioning systems, or ductless units, or combination heat/cooling systems.
    The one thing they ALL have in common is they all have filters that need to be changed or, in some cases just cleaned.
    So, the simple answer to your question, Shellzoo, is ‘YES’.
    The key is to look over the owners manual and see which type maintenance your particular system needs. For many, it’s a simple do-it-yourself repair. For others, you may need some assistance.
    My suggestion is, since we’re halfway through the summer months now, is to check into and perform the necessary maintenance now.
    Good luck!

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