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Tech Tips:

This tech tip features a diagnostic flowchart by Genry Garcia. Thanks, Genry! The name of this document, “The MAD Room,” was chosen as a nod to the MAD-AIR study completed by John Tooley and Neil Moyer, presented in 1989. The teachings from that document played an instrumental role in creating the following diagnostic workflow. Disclaimer […]

Manual J Field Data: Windows

A manual J load calculation will require you to input the U-value for the windows or “fenestrations” on the house. Fenestration is a fancy construction word for window. Figuring out the U-value and SHGC of a window on an existing home is very difficult. But first, let’s dive into what the terms U-value and SHGC […]

Other Great Sources

You may not know this, but the HVAC School podcast began before the website. When I started the podcast, I never intended to create a website, but there was more demand for quick tech tips than the podcast could hold. So, we started hvacrschool.com. In the same way, I never set out to create a […]

Using the Roomulator w/ Chris Hughes

In this episode of the HVAC School Podcast, host Bryan Orr speaks with Chris Hughes of The Energy Conservatory (TEC) about using the Roomulator card and DG-8 manometer for room pressurization testing. Chris provides background on how he came up with the idea for the Roomulator. He wanted an easy way for technicians to […]

A Layered Approach to IAQ

MAD AIR MADNESS! Surviving the House Of Pressure

The MAD House

Akara Hay
#blue collar roots #building science #business #tools

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How to Evacuate an AC system, Full Vacuum Procedure

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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 informative episode, Josh Souders from Copeland joins Bryan to dive deep into heat pump technology, discussing everything from basic operations to advanced features in cold climate applications. The conversation begins with a fundamental explanation of how heat pumps work, describing them as essentially air conditioners with a reversing valve that allows them to provide both heating and cooling. Josh explains the thermodynamic principles that enable heat pumps to extract heat from cold outdoor air and transfer it indoors, achieving coefficients of performance (COP) ranging from 1.5 to 3, making them significantly more efficient than traditional electric resistance heating.

The discussion moves into the broader context of electrification and decarbonization, explaining how heat pumps fit into these environmental initiatives. Josh details how modern cold climate heat pumps have evolved significantly from earlier generations, particularly through the Department of Energy’s Cold Climate Heat Pump Challenge program. This program pushed manufacturers to develop systems capable of maintaining full heating capacity at very low temperatures, addressing historical concerns about heat pump performance in cold regions.

Variable speed technology emerges as a key topic, with Josh explaining how modern inverter-driven compressors can operate across a wide range of speeds – from 900 to 7,000 RPM in their newest A2L products. This capability allows systems to maintain heating capacity in cold weather by increasing compressor speed when needed. The conversation also covers practical considerations for installation and troubleshooting, including the importance of proper defrost cycles, installation location, and the use of riser kits in snowy regions.

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