Indoor Air Quality Guide for DFW Homes

How does your HVAC system control indoor air quality?

Your HVAC system is the primary filter and conditioner for every breath you take inside your home. It circulates and filters the air in a typical DFW home 5-7 times per day, controls humidity levels, and when properly maintained, removes the vast majority of airborne particles including dust, pollen, pet dander, and mold spores.

The EPA estimates that indoor air can be 2-5 times more polluted than outdoor air. In my 10 years of HVAC work across Farmers Branch, Coppell, Irving, Flower Mound, Lewisville, Grapevine, I've seen firsthand how a well-maintained system transforms air quality — and how a neglected one makes it worse. Here's what every DFW homeowner should understand.

What are MERV ratings and which filter should you use?

MERV (Minimum Efficiency Reporting Value) is the industry standard for measuring filter effectiveness, rated on a scale of 1 to 20. Higher MERV means smaller particles are captured — but also more airflow restriction. For residential HVAC systems, you need to balance filtration with the system's ability to move air. Here's my guidance for DFW homes:

Why is humidity control so critical in DFW?

Humidity is arguably the biggest indoor air quality challenge in the DFW metroplex. Our summers regularly push outdoor humidity above 70%, and your AC system is your primary dehumidifier. When operating correctly, your air conditioner removes 5-20 gallons of moisture from your home's air every day.

The ideal indoor humidity range is 40-50%. Below 30%, you'll experience dry skin, static electricity, and cracked wood furniture. Above 60%, you create ideal conditions for mold growth, dust mites, and that uncomfortable clammy feeling.

If your home feels humid even with the AC running, several things could be wrong: your system may be oversized (it cools the air too quickly without running long enough to remove moisture), your ductwork may have leaks pulling in humid attic air, or your evaporator coil may be dirty and underperforming. This is something I check during every maintenance visit.

Are UV-C germicidal lights worth installing?

UV-C germicidal lights installed inside your air handler can be a valuable addition for specific situations. These lights emit ultraviolet radiation that kills or deactivates mold, bacteria, and some viruses on the evaporator coil surface and in the airstream. In DFW's humid climate, mold growth on the evaporator coil is a common problem I see in poorly maintained systems.

I recommend UV lights for homes with: recurring mold issues, residents with compromised immune systems, persistent musty odors from the HVAC system, or homes in areas with heavy pollen (which is most of DFW in spring). A quality UV light system costs $400-$800 installed and the bulbs need replacement every 12-18 months. It's not a substitute for good filtration — think of it as an additional layer of protection.

How often should you clean your air ducts?

This is one of the most over-marketed services in the HVAC industry, and I want to be honest about it. The EPA's guidanceis clear: duct cleaning is recommended only when there's visible mold growth, vermin infestation, or ducts clogged with excessive dust and debris.

For most DFW homes, that means duct cleaning every 5-7 years or after major renovations that produce significant dust. If a company is aggressively selling you annual duct cleaning, be skeptical. What actually matters more is:

What are the biggest IAQ mistakes DFW homeowners make?

After 7 years of residential HVAC in the DFW area, these are the most common mistakes I see: