The Duct We Tend to Forget w/ Joe Medosch

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8 • 985 Ratings

🗓️ 29 October 2017

⏱️ 36 minutes

🔗️ Recording | iTunes | RSS

🧾️ Download transcript

Summary

Do you think of the building envelope as a duct? Do you test it? In this podcast episode, Joe Medosh talks to us about envelope testing and why it’s the future of building health and comfort.

The building envelope is the largest duct in the entire home. However, so many HVAC techs forget about it; they attempt to optimize comfort in the HVAC system and ducts, not the home itself. Techs use Manual J and S, but they don't use the infiltration rate in their calculations. Infiltration in the envelope is a major culprit of discomfort in the home, especially through and around windows.

We use blower doors to determine leakage. During the blower door test, we depressurize the home by a pressure difference of -50 Pa, and we can then calculate the air changes per hour by taking the CFM, dividing it by the volume, and multiplying that number by 60.

The pressure pan is another tool that we use to determine leakage. Pressure pans are semi-quantitative tools that help you figure out where leaks are coming from; you won't find out how much CFM leakage you have, but you will find out if there is CFM leakage.

The commercial HVAC industry has already used "fresh air" in buildings via economizers. However, the residential HVAC industry does not bring fresh air in via the HVAC system. Joe proposes solutions to seal homes but allow fresh air to enter the home in a controlled manner; when we bring that fresh air in, we could implement dehumidification measures to avoid fungal growth.

Joe also discusses:

Windows and energy savings myths
Measuring volume in the home
Common sources of leakage in the home
Gas appliances and combustion/CO risks in tighter homes
Outdoor air and retrofit applications
Backdraft
Balancing ventilation

Check out Retrotec at retrotec.com or purchase Retrotec products from TruTech Tools at trutechtools.com/retrotec. (Use the code "getschooled" at checkout for a discount!)

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Transcript

Click on a timestamp to play from that location

0:00.0	The free training provided by the HVAC School Podcast is made possible because of the generous support from our sponsors.
0:14.3	Testo, Rector Seal, and Carrier.
0:18.3	All right, if you guys have listened to this podcast for any amount of time you know that I kind of
0:24.9	have a little bit of a crush on the test of 605i it's just a stupendous can I say
0:29.9	stupendous and not have it seem like hyperbole I'm gonna choose to say stupendous it is a stupendous and not have it seem like hyperbole I'm going to choose to say stupendous
0:34.8	tool for the investment that you spend on it and it is a great thermal hygrometer and
0:39.6	for those of you who are like what the heck is a thermal hygrometer well I tell you a thermogrometer? Well, let me tell you.
0:43.0	The thermogrometer is basically a digital psychrometer. That's another term for it.
0:47.1	And it measures wet bulb, dry bulb, relative humidity.
0:49.8	At due point, you know, it can extract all of those if you've ever looked at a psych chart.
0:53.8	You need a couple pieces of information, then you can extract the rest.
0:57.2	But what the 605I does really well is that you can measure these readings in duct.
1:01.9	So you can take wet bulb, dry bulb,
1:02.8	dry bulb, dry bulb, relative humidity in the supply, and right there in the
1:08.2	Smart Prob's app it will actually calculate delivered capacity as long as
1:12.3	you enter the CFMs, which is pretty cool.
1:14.3	CFM. I always want to say CFMs, CFM up here. So the 605I is a great tool, but when you
1:20.7	add in what Jim Bergman is doing with the Measure Quick app,
1:24.0	which you can find out more by going to measurequick.com forward slash download now
1:28.0	on that application you know I'm excited about that product, but the Testo Smart probes
1:32.0	and the testo 605I work with Jim Bergman's Measure Quick
1:36.0	app.
	...

Please login to see the full transcript.

Previous episode | Next episode

Disclaimer: The podcast and artwork embedded on this page are from Bryan Orr, and are the property of its owner and not affiliated with or endorsed by Tapesearch.

Generated transcripts are the property of Bryan Orr and are distributed freely under the Fair Use doctrine. Transcripts generated by Tapesearch are not guaranteed to be accurate.