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Air Conditioning

Air Conditioning and Allergies: 6 Things You May Not Have Known

 September 14, 2021

By  Robert Bradford

I have been contending with seasonal allergies since I was a kid. If you have experienced any type of allergies you’re probably like me and have tried any number of lotions, potions, or pots (read Neti Pot not the other kind!) to find some relief.

After living in an old farmhouse with no air conditioning at all to now having Wi-fi enabled A/C that can be adjusted at my every whim I can say with certainty that air conditioning is one of the most reliable and accessible ways to cope with allergies, and not just seasonal allergies.

Many people blame their A/C for spreading allergens throughout their home. On the contrary, if your air conditioner is regularly cleaned and well-maintained, it is extremely helpful in dealing with allergies. Here are the important facts about air conditioning and allergies everyone should know about:

  • Your air conditioner, in itself, is NOT typically the cause of your allergies. More importantly, it can greatly improve the quality of air circulating in your home.
  • Air filtration provided by A/C is proven to help treat various types of allergies, as well as, asthma and rhinitis.
  • High efficiency filters in your air conditioner can reduce the impact of the topmost trigger of year-round allergies in US residences: the house dust mite.
  • Air conditioning can control the humidity in your entire living area thus improving the indoor air quality, which also helps prevent allergies.
  • It is best to rely on your air conditioner during the pollen season and hot summer days to prevent allergens from invading your home.
  • Air conditioner filters, if not cleaned or replaced properly and regularly, can invite allergens such as dust mites, mold, and mildew to grow.

Before we discuss how your allergy attacks can be prevented by your air conditioner, we need to know more about this particular bodily reaction: allergies.

What is an Allergy?

An allergy is a reaction of one person’s immune system when exposed to an unknown substance. This substance could either be pollen from flowers, venom from bees, skin flakes in an animal’s fur or hair, or a specific type of food.

The Mayo Clinic, a not-for-profit organization well-known for its medical research, education, and clinical practice, explained how a person develops an allergy. “An allergy starts when your immune system mistakes a normally harmless substance for a dangerous invader. The immune system then produces antibodies that remain on the alert for that particular allergen. When you're exposed to the allergen again, these antibodies can release a number of immune system chemicals, such as histamine, that cause allergy symptoms.”

The good news is that although some types of allergies cannot be cured, there are ways to treat the symptoms and relieve you from the discomfort.

What are the Different Types of Allergy and Its Causes?

There are seven major types of allergy: drug allergy, food allergy, latex allergy, pet allergy, mold allergy, pollen allergy, and insect allergy.

Since we are discussing how your air conditioning system can help you treat your allergies, we will focus more on the last four types which are airborne.

  • Pet Allergy is caused by exposure to animals’ fur, saliva, urine or dander, which are dead flakes of the skin of animals. A person with a pet allergy often experiences sneezing, runny nose, wheezing, and difficulty in breathing.
  • Mold Allergy is triggered when mold and mildew spores are inhaled. These are fungi that can grow indoors and outdoors. Symptoms include coughing, itching eyes, and restricted breathing.
  • Pollen Allergy is considered one of the most common causes of allergic reactions during spring, summer, and fall. It is sometimes referred to as seasonal allergic rhinitis or more commonly, hay fever. An allergic attack would manifest in a person by sneezing, itching of the nose, eyes, and roof of the mouth, runny and stuffy nose and watery, red, and swollen eyes.
  • Insect Allergy can be caused by being bitten by stinging insects such as bees, wasps, hornets, yellow jackets, and fire ants. Non-stinging insects such as cockroaches and dust-mite can trigger an allergic reaction and do as much damage. In fact, these last two which typically grow indoors are deemed by the medical community as the most common causes of year-round allergies.

How Does Air Conditioning Help You Deal with Allergies?

Modern research shows that the overall temperature, indoor humidity or dampness, and indoor fungal growth has continued to increase worldwide in recent years. These do not just mean a muggier and irritatingly hotter climate, but most allergic reactions are triggered by and flourish in these conditions.

This is where your air conditioner comes in: It is not just efficient in keeping your home cool and comfortable, but it also keeps your allergies and its triggers as far away from you as possible. How so?

 There are two ways air conditioning helps with managing and preventing allergies. A clean and well maintained A/C unit can: 1) filter out allergens from your living space, and 2) improve the quality of indoor air.

Filter Out Allergens

With our doors and windows wide open, we hope to invite the cool fresh air in. However, pollen, animal dander, dust, and mold also stream from outside and invade the air of our private space.

That is why the Mayo Clinic advises allergy sufferers to close all doors and windows and rely on air conditioning for comfort, especially during the pollen season.

The World Allergy Organization Journal also recommends residential air filtration as a crucial component in controlling the environment to help patients with allergic respiratory disease.
There are several air filtration devices you can choose from:

  1. 1
    Whole House Filtration. This is your classic heating, ventilation, or air conditioning system. Air conditioning systems have built-in filters that remove impurities from the air such as dust, pollen and smoke. This ensures better air quality throughout the entire home.
  2. 2
    Portable Room Air Cleaners. If you want a more concentrated air filtration in one particular room at a time or to add to the efficiency of your air conditioner, then you may opt for this one. Because they are small and movable, these air cleaning units can be utilized in spaces that are often occupied like the living room or bedroom. Portable air cleaners promise to lessen the airborne particles that trigger your allergy, and also some vapors and unwanted gases.
  3. 3
    High-Efficiency Particulate Air (HEPA) Filters. This automated air filter functions by pushing air through a fine mesh that traps dangerous allergy triggers. HEPA filters can significantly lessen airborne allergens in your home and can provide clinical benefits to persons suffering from respiratory allergies.

Improved Indoor Air Quality

Some people may define a good quality indoor air as the natural fresh air coming from outside. Unfortunately for allergy sufferers this is not the case. For much of the year pollen, dust, dander, and more come in from outside, lowering the quality of the air in your home.

A well-maintained air conditioner can efficiently cool and dehumidify your home so you can keep the doors and windows closed and allergens to a minimum. As your A/C draws in the hot air from your house and replaces it with cold air, it also is removing plenty of harmful particles from the air, including common allergens. You may know this information already about your A/C. But what most people may not realize is that a tiny creature called the dust mite is also being targeted by the A/C.

The house dust mite is one of the main causes of a year-round allergy in homes worldwide. Their body parts and wastes trigger asthma and other respiratory allergies to some people.
These minuscule arthropods like to live in places with 70% to 80% humidity. If a house is extremely humid and warm, dust mites can survive for the whole year!

Since almost all dwellings contain some dust mites, they are practically inescapable. However, their effects could be reduced by keeping the humidity level in your home to 50% or lower. Your A/C acts as a dehumidifier and in many cases is sufficient to maintain those levels.

However, in some instances and climates it may be necessary to combine an air conditioner with a whole-house dehumidifier to reduce the chances of allergy attacks caused by dust mites.

How Could Your Air Conditioning Expose You to Allergens?

Although the air conditioning system has the potential to control the allergens in your living space and provide excellent indoor air quality for your home, it could be a double-edged sword.

 Instead of helping you manage your allergies, a poorly maintained A/C can make air quality worse if the filter is not replaced regularly or cleaned if it is the washable type. Since it traps allergens such as pollen, dust and pet dander, over time these particles build up in the filter.

Running an air conditioner with a dirty filter will prevent it from functioning properly and eventually it will stop altogether. In the meantime, air forced through a clogged filter circulates the allergy triggers back to the indoor air.

The same can be true for the buildup of humidity, which can occur because of a congested filter. If the A/C is also not regularly checked for refrigerant leaks, the inside of your home could be more humid than ever.

How often you replace your filter will depend on the circumstances of your home. The minimum is once a year. You may want to increase it to twice a year if you have pets, live in a dusty or humid environment, or have severe allergies. A client with a woodworking shop in his basement changed the filter once a month so consider the activities in your home when deciding how often to change your filter.

 Having your heating and air conditioning systems cleaned by a professional annually will also alert you to any potential weak spots in your indoor air quality. They should also be able to suggest how often you need to change your filter.

How Do You Properly Maintain Your AC to Prevent Allergies?

There are several ways to properly maintain your air conditioner that are easy and inexpensive:

  1. 1
    Replace your AC air filters regularly; more frequently if you have pets.
  2. 2
    Clear the ductwork from dust, both above and below your house.
  3. 3
    Make sure there are no leaks and drips in any part of the unit.
  4. 4
    Be mindful of any gaps or open doors and windows while your air conditioning unit is running.

Robert Bradford


I'm Robert Bradford. I've been in the heating and air conditioning industry for 30 years. Ov​​​​​er 40 if you count the years I helped my father as a kid. On this site, I share everything I've learned about finding the best HVAC contractors and equipment for your home. I'm happy to say that over the last few years, The Comfort Academy has grown into a trusted site with thousands of informed site visitors each year.

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