Our Current HVAC Mess – GreenBuildingAdvisor

By Martin Holladay | December 5, 2025

Most building scientists and home performance experts are troubled by the low level of expertise exhibited by the average residential HVAC contractor in North America. So many residential heating, air-conditioning, and ventilation systems have major problems that scores of highly paid consultants make a good living diagnosing HVAC problems and suggesting solutions.

In my 2019 article “Still Fighting the Same Battles, 20 Years Later,” I wrote, “I’ve come to describe residential HVAC contractors as ‘uniquely incompetent’ … Most HVAC contractors can’t perform an accurate Manual J calculation, even though it is code-mandated. Most residential HVAC equipment is oversized. Many duct systems are unacceptably leaky. Many duct systems are located outside of a home’s conditioned space. Most ventilation systems are poorly designed, poorly installed, and rarely commissioned … This is an industry in crisis.”

What about solutions?

My intention is not to knock an entire industry. Rather, I’d like to help come up with some practical solutions to these problems. I decided to contact a group of building science experts, mechanical engineers, and savvy HVAC contractors to ask about the existing crisis in residential HVAC installations and to solicit suggested solutions.

In the email I sent out, I wrote, “How can we help the residential HVAC industry reform and improve? Your ideas don’t have to be easy to implement—you can make suggestions in the vein of, ‘If I were emperor of the world, here’s what I’d do …’”

For better or worse, my email also included a description of residential HVAC contractors as “uniquely incompetent—unlike framers, electricians, and plumbers, who generally avoid egregious errors.” Understandably, several of the experts who responded to my query bristled at the phrase “uniquely incompetent.”

Andy Ask, an independent HVAC consulting engineer in Cape Coral, Florida, responded, “I agree with the ‘uniquely’ but…