The paired concepts every later module assumes fluency with — sensible vs. latent cooling, static vs. velocity pressure, superheat vs. subcooling, efficiency ratings, air distribution strategy, and indoor air quality.
This is the hallmark module of the program. HVAC training often teaches equipment first and the underlying physics second, if at all — this module deliberately reverses that order, working through the paired and grouped concepts that distinguish an engineer who can explain why a system behaves the way it does from one who can only follow a checklist. Sensible vs. latent cooling, static vs. velocity pressure, CFM vs. ACH, superheat vs. subcooling, COP/EER/SEER/HSPF, CAV vs. VAV, building pressure, ventilation vs. infiltration, hydronic vs. air systems, chilled water vs. DX, open vs. closed loops, air balancing, diversity factors, economizers, heat recovery, and indoor air quality — eleven sections, each grounded in how the concept actually shows up on a real system.
By the end of this module you should be able to explain, from first principles, why two units with identical EER ratings can have meaningfully different SEER ratings, and why a system reading low superheat and low subcooling together points to a low refrigerant charge rather than a random fault — questions Module 7's refrigeration content and Module 14's energy efficiency content each build on directly.