Allergies Acting Up Indoors? How Austin Homes Trap Allergens (and How to Fix It)

If your allergies seem worse inside your home than outside, you’re not imagining it. Austin is one of the most notoriously difficult allergy cities in the country — cedar fever alone shuts people down every winter — and your home’s HVAC system can either make that problem significantly worse or genuinely help control it. The difference comes down to what’s circulating through your air system and whether anything is actually filtering it out.

Austin’s Allergy Reality: What’s Actually in Your Air

Austin residents deal with a longer and more varied allergy calendar than most American cities. Mountain cedar (Ashe juniper) releases pollen starting in December and can run through February — it’s so potent that locals literally call it “cedar fever” because the reaction mimics flu symptoms. Oak pollen follows in spring. Grass pollens carry through summer. Then mold spore counts spike every time we get significant rain, which is unpredictable but happens year-round.

Inside your home, those outdoor allergens get company from dust mites, pet dander, and mold that can grow in humid areas like ductwork, drain pans, and bathroom walls. The EPA estimates that indoor air can be 2–5 times more polluted than outdoor air — partly because allergens concentrate indoors without the diluting effect of open air, and partly because modern energy-efficient homes are well-sealed, which limits natural ventilation.

Your HVAC system sits at the center of this problem and the solution. Every time it cycles on, it pulls air from your living space through a return duct, passes it through a filter, conditions it, and pushes it back out through supply vents. If the filter isn’t capturing allergens effectively — or if the ducts are loaded with dust and debris — the system is actively spreading whatever it picks up.

The Filter Problem: Why Your Basic Filter Isn’t Enough

The standard fiberglass filter that comes with most HVAC systems has one job: protecting the equipment from large particles. It does almost nothing to capture the fine particles that trigger allergy symptoms — dust mite allergens, mold spores, and pollen particles that are measured in microns.

Filter efficiency is measured on the MERV scale (Minimum Efficiency Reporting Value), which runs from 1 to 16 for residential use. Here’s a practical breakdown:

• MERV 1–4: Basic fiberglass filters. Catches lint and large dust. Misses almost everything that affects allergies.
• MERV 8: Pleated filters. Captures mold spores, dust mite debris, and some pollen. A solid baseline upgrade for most homes.
• MERV 11–13: The sweet spot for allergy sufferers. Captures fine dust, pet dander, smoke particles, and most pollen. Works in most residential systems without causing airflow problems.
• MERV 14–16: Near-HEPA performance. Very effective but can restrict airflow in systems not designed for the extra resistance — check with a technician before using these.

One important note: a higher MERV filter that’s clogged and overdue for replacement is worse than a lower MERV filter that’s fresh. In Austin’s summer, check your filter monthly. If you have pets or anyone in the household with significant allergies, every 30 days is a good rule regardless of what the filter packaging says.

Duct Sealing and Cleaning: Addressing the Source

Even the best filter can’t help if your ductwork is the problem. Ducts in unconditioned attic spaces accumulate dust, insulation fibers, and potentially mold over years of use. Leaky duct connections can pull attic air — which is extremely hot and can carry attic dust and insulation particles — directly into your airstream, bypassing the filter entirely.

Duct sealing is one of the most effective and underutilized indoor air quality improvements available. When leaks in the return-side ductwork are sealed, you eliminate the pathway for unfiltered attic air to enter the system. As a bonus, sealed ducts also improve system efficiency and reduce energy costs — a double win.

Duct cleaning is a separate question and worth discussing honestly: it’s genuinely beneficial in specific situations (significant visible mold, vermin infestation, post-renovation dust accumulation) but often oversold as a routine maintenance item. If your ducts were cleaned within the last 5–7 years and you haven’t had any major disturbances, cleaning may not be your highest-value next step. A technician can inspect and advise.

UV Air Purifiers: Real Technology, Not a Gimmick

UV germicidal lights installed inside your air handler use ultraviolet-C radiation to neutralize mold, bacteria, and some viruses as air passes the lamp. This is the same technology used in hospitals and commercial buildings, scaled for residential HVAC systems.

UV purifiers don’t replace filtration — they address the biological allergens and pathogens that even high-MERV filters can miss. They’re particularly valuable in humid climates where mold growth on the evaporator coil is a real concern. Austin’s humidity spikes enough during rainy stretches that coil mold is not uncommon, and a UV light aimed at the coil prevents that growth rather than just filtering it downstream.

There are also whole-home electronic air cleaners and ionizers available — the technology and effectiveness vary significantly by product. Our team can walk you through what makes sense for your home’s specific needs and your family’s health concerns without pushing you toward something you don’t need.

Humidity Control: The Mold and Dust Mite Connection

Dust mites and mold — two of the most common indoor allergy triggers — both thrive in humidity above about 50%. Central Texas delivers enough ambient humidity that many homes run at 55–65% relative humidity indoors without any intervention, which is a near-perfect environment for both.

Your air conditioner dehumidifies as it cools, but it can only do that job when it’s running a full cooling cycle. In the shoulder seasons (spring, fall) when it’s not hot enough for full AC use, indoor humidity can climb quickly. A whole-home dehumidifier installed in the HVAC system runs independently of the cooling cycle, maintaining 45–50% relative humidity year-round. At that level, dust mite populations drop significantly, mold growth stalls, and many allergy sufferers notice substantial improvement even without changing anything else.

How Insulation Fits the Allergy Picture

This one surprises people. Inadequate attic insulation doesn’t just cost you money on your energy bill — it contributes to allergy problems in two ways.

First, a poorly insulated attic allows extreme heat to radiate into the living space, which increases the pressure differential between your conditioned space and the attic. That pressure difference drives air infiltration — attic air, with its dust, insulation fibers, and potential mold spores, gets pulled into the living space through every gap and crack. Second, extreme temperature swings in an under-insulated home cause condensation issues that promote mold growth in walls and ceilings.

Proper attic insulation creates a better thermal and pressure boundary, reducing the infiltration of outdoor allergens and the conditions that promote indoor mold. It’s one of those improvements that pays dividends on energy costs, comfort, and indoor air quality simultaneously.

Building Your Home’s Allergy Defense Plan

You don’t have to tackle everything at once. Here’s a practical priority order for most Austin homes:

• Start with the filter. Upgrade to MERV 11–13 and commit to monthly replacements during peak allergy seasons. Lowest cost, immediate impact.
• Get an AC tune-up. A technician will inspect the evaporator coil for mold, clear the drain line, check for duct leaks, and verify the system is running efficiently. Service Wizard’s 26-point tune-up covers all of this for $90. Check current specials for any active promotions.
• Address duct leaks. If your technician finds significant leakage, duct sealing delivers outsized results for both air quality and efficiency.
• Consider a UV light. If mold on the coil is a recurring issue or you have family members with significant respiratory sensitivities, a UV purifier is a practical next step.
• Evaluate insulation. If your home is older or your energy bills suggest your attic isn’t performing, an insulation assessment will tell you where you stand and what improvement is realistic.

Service Wizard serves Austin and 29 surrounding communities — from Cedar Park to Kyle to Georgetown — with licensed HVAC technicians who can assess your home’s specific situation. We don’t use high-pressure sales tactics, and we give you upfront pricing before any work begins. Our Happy Money Promise means if you’re not satisfied, we make it right.