Manual J or Not? How to Tell If Your HVAC Design is Bogus

If you ask for the HVAC design calculations for your project, you might get handed literally anything from scratches on a napkin to a 50 page jargon-filled binder. Here’s an example of a calculation that might look legit, but is actually very misleading. Learn more about HVAC Design: https://buildingperformanceworkshop.com/training Get 1-on-1 help in consultation with Corbett: https://buildingperformanceworkshop.com/video-consulting

Roasting the Home HVAC Industry on National TV: Technicians vs. Mechanics

HVAC technicians will someday be the masters of the science of homes, but right now it's not looking too hot. Hear from Jim Bergmann, one of the world's HVAC legends, why most HVAC installs are wrong from the minute the load calculations are started using Manual J, Manual S, and Manual D without using a blower door first.

Watch the show at https://HomeDiagnosis.tv

Support our work changing the building industry: http://Patreon.com/HomeDiagnosisTV

Start testing your HVAC installs with: https://measurequick.com/

Get your blower door at: https://www.trutechtools.com/system-blower-doors-and-duct-testers.html

Manual J Load Calculations: What, Why, How, When, and Who?

Now that Corbett has been doing HVAC load calcs for almost a decade, he's ready to make this very long (and also much too short) video tutorial about the what, why, how, when, and who of heat load calcs for sizing your HVAC equipment.

I Turned My A/C Off All Day at 106 Degrees

Dear Corbett:

I thought I would send this your way.  I live in the Central Valley of California.  Yesterday it reached 106 degrees.  I did an experiment with my house.  My 1,883 sq./ft. house had a deep energy upgrade over three years ago.  The heating and cooling unit is a 2 stage/2 ton heat pump with no back-up heat.  The second stage of cooling is disconnected so I am cooling with 1.4 tons.  That is one ton for every 1,345 sq./ft.

Yesterday morning I left the house at 7:40 am.  It was 75 degrees in the house and 75 degrees outside.  I closed all of the blinds, turned the HRV off and turned the Heat Pump off.  In other words, I let the house float.  It got up to 106 degrees in Stockton yesterday.  Luci my bride got home at 5:40 in the afternoon and the house was 78 degrees.  She turned the thermostat back on and it brought the temp back to 75 in 30 minutes.

This stuff really works.
Keep up the GREAT work;
Dick Rome

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Dear Dick-

You are awesome. I'm not sure I know many other home performance experts who have fixed their own homes- most of our families have to suffer at home while we help other people get comfortable. Thanks so much for sharing the good word!

~Corbett