While both UV light and HEPA air filtration systems can be effective in improving indoor air quality and reducing the presence of mold spores, here are some reasons why a whole home HEPA air filtration system may be considered better than UV light:

1. Filtration: HEPA air filtration systems physically capture mold spores and other airborne particles in a filter, while UV light simply sterilizes them. HEPA filters can trap particles as small as 0.3 microns, while UV light can only sterilize particles that are exposed to it directly.
2. Comprehensive: A whole home HEPA air filtration system can clean the air throughout the entire home, while UV light is typically installed in a single room or area.
3. No ozone: Some UV light air purifiers emit ozone, which can be harmful to some people, particularly those with respiratory issues. HEPA air filtration systems do not produce ozone.
4. Cost: While HEPA air filtration systems may have higher upfront costs, they are typically less expensive to operate over the long term compared to UV light systems, which require replacement bulbs.
5. Maintenance: HEPA air filters require periodic replacement, while UV light bulbs need to be replaced regularly as well as cleaned to maintain optimal performance.

Overall, a whole home HEPA air filtration system can be a more comprehensive and effective solution for improving indoor air quality and reducing the presence of mold spores compared to UV light systems. It is important to consult with a qualified expert to determine the best approach to improving indoor air quality in a given situation.