Some individuals, including certain AC salesmen, often promote UV lights as a one-size-fits-all solution to poor indoor air quality. This misleading portrayal frequently results in false expectations and a hefty financial investment. 

In Texas, regulations prohibit salesmen, including those in the AC industry, from discussing mold-related topics without proper licensing and expertise. These laws aim to prevent misinformation and deceptive practices. UV lights serve as a prime example of why such regulations are necessary. 

One common question is whether UV lights effectively kill microorganisms. The short answer is yes. However, the extent of their effectiveness, especially against mold and other harmful microorganisms, is often exaggerated in marketing and sales tactics. The time required for UV lights to eliminate mold spores varies on factors like light intensity and distance. Even under ideal conditions, UV lights may only affect surfaces directly exposed to the light rather than killing airborne contaminants. 

Given these limitations, UV lights have minimal impact on indoor air quality. While they may sterilize the duct’s surface where they are installed, they are ineffective against particulates that pass through the light quickly. Investing in scientifically proven methods may significantly improve indoor air quality while avoiding unnecessary expenses.

MERV, or “Minimum Efficiency Reporting Values”, serve as a standardized measurement system used to assess air filter effectiveness in capturing airborne particles. Ratings typically range from 1 to 16, with higher ratings indicating better filtration efficiency. 

Unlike UV lights, MERV-rated AC filters offer substantial benefits for enhancing indoor air quality. However, they also come with certain drawbacks. While these filters effectively trap airborne particles, they do not actively eliminate microorganisms. Instead, they contain them within the filter while negative pressure is applied. 

Like most AC systems, the AC unit itself eventually reaches the owner’s desired temperature and turns off. When the unit turns off, the MERV filter, which is under negative pressure, eventually reaches normal atmospheric pressure and can release the trapped contaminants back into the air. Similarly, In some HVAC systems, particularly older and poorly designed ones, gaps or leaks around the filter edges may allow unfiltered air to bypass the filter, compromising its effectiveness.

Another issue with MERV filters is buildup. As with any AC filter, moisture and duct accumulation over time can impede airflow, reducing filter efficiency. When airflow becomes restricted, especially in humid environments, mold growth may occur. This is one of the many reasons why air filters need to be changed on a regular basis.

Furthermore, MERV-rated filters are more costly than non-MERV-rated filters and improper installation or use can restrict airflow further, leading to strain on the system’s components and additional costly repairs, running from hundreds to thousands of dollars.