Indoor air pollution is a pressing health risk for all Americans. It’s particularly concerning for those with bad allergies. Triggers can worsen symptoms severely, to the point of being debilitating. Your HVAC system plays a role in indoor air quality (IAQ) and can impact your allergies. With that in mind, let’s explore some truths and misconceptions plus steps you can take for better IAQ.

HVAC System Configurations

There is a wide range of HVAC systems, including air conditioners, heat pumps, furnaces and boilers. Some people link central and forced air systems to worsening allergies, but this is generally a misconception. Blown air can negatively affect IAQ, but when that happens, it’s generally a byproduct of a more fundamental air quality issue. Ducted systems can even be a boon due to their ease of adding air purifiers as well as other features.

HVAC Filters

If you do have central and/or forced air, you have one or more supply vents. These vents have an HVAC filter that helps to keep dust out of your equipment and ducts. They can also play a role in reducing allergy triggers. MERV stands for minimum efficiency reporting value. It’s a measure of filter effectiveness. A higher MERV filter will restrict airflow. That makes it important to choose a MERV rating no higher than your system supports. But most modern HVAC units are fine with MERV 13 and higher. You can even find HVAC filters that manufacturers design specifically for allergy sufferers.

Clean Ductwork

Dusting your home regularly is important, as is using a high-quality HVAC filter and swapping it out as needed. But despite those efforts, dust will collect in your ducts over time. That accumulation leads to more particulate matter and gases in your air. It can also be a breeding ground for dust mites plus mold and fungal spores. The National Air Duct Cleaners Association recommends cleaning your ducts every three years. For a person with bad allergies, the general advice is to do this every other year.

Whole-Home Air Purification Systems

IAQ experts agree that the best way to remove allergens from your indoor air is with an air purification system. A whole-home air purifier is typically a system integrated into your central HVAC. If you don’t have central air, you can opt for one or more room air purifiers to provide the coverage you need. The integrated solutions are generally more affordable as they take advantage of the existing air handler. Note that room air purifiers are not the same as portable units. Portable air purifiers only filter in your immediate space. Room air purifiers typically provide 1,000 square feet or more of coverage.

Most air purifiers on the market have three stages. A prefilter protects the system and extends the life of the more expensive filter media. A high-efficiency particulate air filter provides mechanical filtration, and an activated carbon stage provides absorptive filtration.

HEPA Filtration

Mechanical filtration is important because it filters out particulate matter (PM) that triggers allergies. This includes pollen, dust and animal dander. But it also removes the fine PM associated with respiratory and cardiovascular diseases. Many air purifiers use a True HEPA filter that conforms to the Department of Energy standard, eliminating 99.97% of particles down to 0.3 microns. This is generally good enough for allergies, but you can also opt for medical-grade HEPA: 99.995% down to 0.1 microns.

Activated Carbon Filtration

Most allergens are 0.5 microns in size or larger. Activated carbon does filter some particulate matter but nothing that small. As a result, it isn’t absolutely necessary for an allergy sufferer. But it does remove odors, fumes and smoke that can be irritants. It also removes gases, including volatile organic compounds (VOCs). Many household cleaners give off VOCs that can irritate your eyes, nose and throat.

Air Changes Per Hour

Cubic feet per minute (CFM) is a measure of how much air an air purification system moves. Air changes per hour (ACH) is CFM in the context of the ceiling height and square footage of your home. The Centers for Disease Control and Prevention recommend 5 ACH as a minimum all homeowners should target. Air purifiers rated at 6 ACH are readily available. These systems should be more than enough for the average person with allergies. If your allergies are particularly severe, it’s a good idea to discuss ACH with your allergist.

UV Germicidal Light

While eliminating PM is the most important step for allergies, UV-C germicidal light can play an important role as well. It can neutralize mold and fungal spores and dust mite eggs. This is in addition to neutralizing viruses and bacteria.

You can opt for an air purifier with a UV-C stage. The problem there is that you want a high ACH. UV light is actually more effective with lower airflow. This is because the microorganisms spend more time exposed to the light. This is why many experts recommend UV lamps that your HVAC technician can install in your ducts.

Humidity Control

Relative humidity plays a role in allergies as well. The EPA generally recommends an indoor RH between 30% and 50%. When your home is outside that range, it’s more prone to pollutants, and you’re more prone to irritation.


A dehumidifier is very important for a person with allergies. It helps to avoid high humidity levels in the summer. You can opt for a whole-house dehumidifier that integrates with your HVAC system. Air purifier and dehumidifier combination units are also available. These systems work by removing moisture from the air. When there’s less moisture, the air can hold less PM. The environment is also much less hospitable to irritants like mold and dust mites.


Many think of spring and summer as allergy season. But allergies can be pretty bad in fall and winter, too. Adding moisture to your indoor air with a humidifier will soothe your eyes, nose and throat and make you less prone to irritation.

Energy or Heat Recovery Ventilator

Modern construction leads to energy-efficient homes but little to no natural ventilation. This is a problem for people with allergies, as it can lead to a higher concentration of triggers. One way to alleviate that is an energy recovery ventilator (ERV) or heat recovery ventilator (HRV) that adds fresh air without introducing more triggers. The main difference between an ERV and a heat recovery ventilator (HRV) is that an ERV helps a little with humidity, while an HRV does not.

Seasonal HVAC Tune-Ups

Even if it’s not time to clean your ductwork, remember to schedule seasonal tune-ups: one for your cooling system in spring and one for your heating system in fall. This is good advice for a host of reasons. It’s important for your allergies because your technician will clean your HVAC equipment.

Your Local IAQ Experts in Boise

If you’d like reduce allergy triggers in your home, Access Heating & Air Conditioning can help. Our company has served Boise, ID and the surrounding areas for more than 50 years. We install all manner of single-zone, multi-zone, ducted and ductless heating and cooling equipment. Our team also includes expert plumbers who install and repair plumbing fixtures and toilets as well as tank and tankless water heaters.

Get in touch with Access Heating & Air Conditioning today to schedule an appointment or learn more about our services.


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