Heat recovery only pays off when the fundamentals are right. This section is the engineering backbone of HeatRecoveryHub — the thermodynamics, fluid mechanics, and certification math you need before specifying a single unit.

Whether you're sizing a counterflow core, modelling frost risk, or proving savings to a CFO, start here. The index below maps the section so you can jump straight to the concept you need.

What this section covers

• Psychrometrics — the moist-air properties behind enthalpy recovery, and how to read them.
• Effectiveness–NTU — why it beats rule-of-thumb sizing for real exchangers.
• Frost formation — causes, limits, and the mitigation strategies that work.
• Counterflow vs crossflow — the trade-offs that decide efficiency and footprint.
• Heat recovery's role in HVAC, decarbonization, and modern building codes.