EP254 Mold, Moisture, and Missed Details: Lessons From the Building Science Trenches With Kohta Ueno (January 2026)

QUOTES from the episode:

"Most building failures aren't mysterious. They're just ignored fundamentals."

"If you demand museum-level humidity, you're no longer building a house. You're building a museum."

"Moisture meters don't solve problems. They show you patterns. The thinking solves the problem."

 

In this episode of the Building HVAC Science Podcast, Eric Kaiser is joined by Kohta Ueno, principal and co-owner of Building Science Corporation, for a wide-ranging discussion on building failures, moisture, HVAC, and the practical realities of diagnosing real-world problems. Kohta shares his unconventional path into building science, from small remodeling jobs and a PBS NOVA episode to decades of forensic investigations alongside Joe Lstiburek, one of the field's most influential voices. The conversation quickly moves from origin stories into what really matters: how buildings fail, why those failures are often predictable, and how much cheaper it is to solve problems on paper than after construction.

 

A major theme is moisture management, especially in high-performance and multifamily buildings. Kohta explains how seemingly small details, like window sill slope, back dams, airflow settings, and interior air seals, routinely separate durable buildings from expensive failures. He also highlights a growing perfect storm in modern construction: oversized HVAC equipment, high ventilation rates, poor commissioning, and limited dehumidification, particularly in smaller units. The result is mold, humidity complaints, and systems that technically run but fail to control moisture.

 

The episode closes with a practical look at diagnostic tools and methods. Kohta emphasizes pattern recognition over single-point measurements, combining moisture meters, thermal imaging, pressure diagnostics, and blower door testing to understand how air, heat, and moisture actually move through buildings. He encourages listeners to use freely available Building Science Corporation research and Joe Lstiburek's Building Science Insights as foundational resources, reminding the audience that most building failures are not mysterious. They are repeatable, understandable, and avoidable if the fundamentals are respected.

 

Kohta's LinkedIn: https://www.linkedin.com/in/kohta-ueno-472a4/

Links mentioned in the episode:

Our Current HVAC Mess

Experts discuss problems with residential HVAC systems as a first step toward defining solutions

https://www.greenbuildingadvisor.com/article/our-current-hvac-mess

 

Proposed Solutions for Residential HVAC Problems

Experts suggest ways to improve the quality of residential heating, ventilating, and cooling equipment installations

https://www.greenbuildingadvisor.com/article/proposed-solutions-for-the-residential-hvac-industry

 

A presentation on my investigations of multifamily humidity problems:

Multifamily Humidity Control Problems: Muggy Mayhem

https://buildingscience.com/sites/default/files/presentation-docs/2021-05-06_nesea_be21_muggy_mayhem_ueno_for_pdf_0.pdf

 

I have done a presentation on the diagnostic tools I use in my buildings forensic work; here's the slide deck:

NESEA BE19 Tools of the Trade for Building Diagnostics

March 14, 2019

https://www.buildingscience.com/sites/default/files/2019-03-14_nesea_be19_ueno_tools_trade_diagnostics_for_pdf.pdf

2019-03-14_NESEA_BE19_Ueno_Tools_Trade_Diagnostics.pdf

 

And here's a YouTube video:

 

Tools of the Trade for Building Diagnostics with Kohta Ueno

https://www.youtube.com/watch?v=kCZIJFXDl9Q&t=2978s&ab_channel=TheBSandBeerShow

 

The complete rundown of Joe Lstiburek's columns:

 

https://buildingscience.com/document-search?search_title=&search=&field_doc_topics=All&field_doc_document_type=3&items_per_page=10

 

And some of the research reports we did under Building America:

 

https://buildingscience.com/document-search?search_title=&search=&field_doc_topics=All&field_doc_document_type=8&items_per_page=10

 

This episode was recorded in January 2026.