It’s an IAQ Deep Dive…part two! Matt welcomes Sean Harris back to the studio to continue their discussion indoor air quality improvements for existing homes, focusing on mold prevention, HVAC upgrades, filtration, and dehumidification—especially in hot, humid climates like Texas. Sean emphasizes that mold issues often stem from leaky ductwork in unconditioned spaces, poor ventilation, and high humidity, leading to compromised air quality. Instead of cleaning mold, he recommends removing contaminated materials and improving source control. For HVAC systems, Sean suggests keeping ductwork in conditioned space, using MERV 13+ filters, and installing a ventilating dehumidifier to maintain humidity below 50%. He warns against running HVAC fans continuously, as this can pull humid air into the system, worsening mold issues. He also recommends in-room HEPA filtration (isuch as IQAir or Austin Air) over whole-home air purifiers. They discuss (and advise against) gimmicky air purification methods like UV lights and ionizers, which can create harmful byproducts. Instead, homeowners should monitor IAQ with smart sensors, track humidity, and optimize their home’s ventilation and filtration. Sean emphasizes "optimization over maximization"—cost-effective solutions like air sealing, replacing moldy ductwork, and using high-quality air filters rather than full HVAC overhauls. Both Matt & Sean encourage homeowners to prioritize practical, science-backed IAQ improvements for a healthier living environment. Thank you to episode sponsor Mbrico. Learn more at: https://www.mbricotiledecks.com/ Find Sean Harris on the Web: Website: https://iaqtexas.com/ Instagram: https://www.instagram.com/aerosealofaustin/ Facebook: https://www.facebook.com/IAQTexas/ Get your BUILD SHOW Gear Here - https://build-gearstore.com/ Subscribe and follow my Podcast on Apple or Spotify! Apple: https://apple.co/32AOwgU Spotify: https://spoti.fi/3FXNg4X Sign up for our twice-weekly newsletter: https://buildshownetwork.com/newsletter To sponsor a video or advertise with us visit: https://www.buildproductions.com Want to learn more about building? http://thebuildshow.com/ The Build Show on Instagram: https://www.instagram.com/thebuildshow/ Huge thanks to our Show sponsors Builders FirstSource, Huber, Pella & Viewrail for helping to make these videos possible! These are all trusted companies that Matt has worked with for years and trusts their products in the homes he builds. We would highly encourage you to check out their websites for more info. https://www.bldr.com http://www.Huberwood.com https://www.pella.com https://www.Viewrail.com