#AHR

Tech Tips:

Title: NATE Testing & Review Description: Bryan Orr with HVACRSchool.com will offer a general, technical NATE review from 8am-11:30am and proctor a session of North American Technician Excellence (NATE) technician certification testing in the afternoon from 1pm-5pm. The Review will cover elements of the CORE, Air Conditioning and Heat Pump exams and how the concepts apply […]

The 10 Commandments of the HVAC/R Technician

One trait I've seen with good technicians is that they take their jobs VERY seriously, but they learn not to take themselves too seriously. A few months ago, I had someone tell me online that I must think I'm the A/C “god” because I'm always telling everyone the “right” way to do things. This got […]

Ramiro Ramos

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this short Q&A podcast, Bryan answers a listener-submitted question about apps for doing proper loads. Fred specifically asks about apps or charts that can help an HVAC contractor determine the insulation value of a home without assuming numbers or drilling into walls during load calculations.

Load calculations account for all the ways that BTUs can enter or leave a home: conduction, convection, and radiation. Insulation prevents heat transfer via conduction, so it’s important to the load calculation process. High-end HVAC design software like Wrightsoft and Kwik Model 3D will have these features built into them (based on the age and location of the home). ASHRAE’s handbook also has tables and data with R-values and U-factors to help you out with Manual J load calculations.

RED Calc is an app that allows you to calculate a wall’s R-value with measurements, including surface and air temperatures indoors and outdoors. This RED Calc software is available through the U.S. Department of Energy, as is REScheck. The DOE insulation fact sheet is also quite valuable, as are The Engineering Toolbox and materials straight from the insulation manufacturers.

The best way to get a comprehensive load calculation is to have a lot of tribal knowledge about how houses are built in your area, analyze energy bills, and combine tools like RED Calc with building performance tests.

RED Calc is available through the U.S. DOE at https://basc.pnnl.gov/redcalc. REScheck is available at https://www.energycodes.gov/rescheck.

ASHRAE’s resources are available at https://ashrae.org/technical-resources.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.