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HVAC School - For Techs, By Techs

Nov 2, 2023

Nikki Krueger and Genry Garcia return to the podcast to talk about a recent IAQ & dehumidification case study on a vintage home in Miami. The home was very clean but had a musty odor and VOC concerns. You can read the case study in the “Literature” section at or

Blower door tests and ZPD revealed that the home was leaky, and the crawlspace was also not properly encapsulated. The options were to tighten the building and/or mitigate the problem by improving the HVAC system. The homeowners chose to improve the HVAC, which Genry did by installing a ventilating dehumidifier (Santa Fe Ultra98H), reducing system tonnage (3.5 to 2 tons), and putting in new ductwork.

One of Genry’s key tips to address intermittent moisture issues is to pay attention to fluctuating pressures, not just under the blower door test conditions. Ongoing monitoring is crucial in these studies to measure the home under several different typical conditions. He also relies on blower door tests to determine if encapsulation is necessary or needs improvement, as insulation and encapsulation can bring new issues in their wake. 

Extensive testing and working with other contractors (such as home insulators) are the best ways to get a solution that makes the homeowner happy. We need a holistic approach to design to achieve a homeowner’s IAQ and comfort goals, not necessarily following strict design guidelines to a T.

Nikki, Genry, and Bryan also discuss:

  • Zonal pressure diagnostics (ZPD)

  • Dehumidifier ductwork

  • Dehumidifier selection

  • Attic encapsulation, condensation, and duct leakage


  • The importance of IAQ case studies and the insights we can get from them

  • Effects of insulation

  • Dehumidifier performance in part-load conditions

  • Mechanical equipment design

  • Consulting the ACCA design manuals

  • Maintaining equipment and sustaining positive results


Stay tuned for the companion tech tip.

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