HVAC Design: Recognize Proper HVAC Design and the Importance of Manual J & S

with Alex Meaney

Planning on replacing or installing a new HVAC system? Don’t let your contractor skip the most important step by running Manuals J and S. In Part A of this two-part class, Alex Meaney explains why these calculations are worth paying for, how they protect your comfort and your wallet, and the warning signs that your contractor may be cutting corners. Learn why “bigger isn’t better” when it comes to HVAC and how sizing your system properly can make all the difference in performance and efficiency. This class will leave you informed, confident, and ready to make smarter decisions about your home’s HVAC. Don’t miss Part B, where we dive into Manuals D and T.

In this mini class, you’ll learn: 

  • The purpose of Manual J, load calculation and equipment selection, the cyclical design process, and what happens when the system experiences failures. (3:26)

  • The difference between sensible heat and latent heat, and how each affects your body’s cooling system. (9:16)

  • Why humidity and insulation are tricky, the roles of conduction, convection, and radiance in load calculations, and how the law of diminishing returns applies. (12:58)

  • How convection and square feet per ton are measured, and the basics of radiance. (16:49)

  • The purpose of Manual S, how to verify if your contractor performed the load calculation correctly, why things are measured in tons, and the calculating system capacity according to AHRI.  (21:47)

  • The importance of matching up Manual J and S, why bigger isn’t always better, and why manufacturer performance data can be difficult to find. (28:29)

  • How sizing heat pumps saves money, how sizing works for cold and humid climates and for hot and dry climates, what it means to embrace the spirit of the code, and how to evaluate a contractor. (33:34)

Download the transcript here.

Watch More Episodes From Our HVAC + D Mini Class Series here:
https://changetheairfoundation.org/understanding-hvac-d/

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