Longer Allergy Seasons Raise the Stakes for Fall HVAC Maintenance

Fall doesn't bring relief from allergies the way many people expect. Ragweed and other weed pollen typically peak in September and October, and mold spores rise along with wet weather and decaying leaves. According to the Asthma and Allergy Foundation of America, the first fall frost now arrives about 10 days later than it did 30 years ago, which stretches out the season when these allergens linger both outside and inside the house.

Your heating and cooling system plays a real role in how much of that gets into your indoor air. Experts point to MERV 13 filters (a rating scale for how well a filter traps small particles) as a good option for catching pollen, mold spores, and pet dander, but only if your system's ductwork and blower can handle that filter without straining. A filter that's too restrictive can cut airflow, raise energy use, and even cause a furnace to overheat or an air conditioner's coil to freeze, so the right choice depends on your specific equipment.

Filters aren't the whole picture. Fall maintenance visits often check for moisture problems, since standing water or excess humidity in the system can feed mold growth, and for gaps or backward-installed filters that let air sneak past unfiltered. Replacement schedules vary too: a basic 1-inch filter usually needs changing every one to three months, while thicker filters can last six to twelve months, though pets, dust, and heavy pollen days call for more frequent checks.