HRV (Heat Recovery Ventilation) and ERV (Energy Recovery Ventilation) systems both recover energy from exhaust air — but the mechanism and the right application differ significantly.
How HRV Works
An HRV uses a heat exchanger — typically a cross-flow or counter-flow plate type — to transfer thermal energy from exhaust air to incoming fresh air. Only sensible heat is transferred; moisture stays on its respective side of the exchanger.
How ERV Works
An ERV uses a membrane or desiccant wheel that transfers both sensible heat and latent heat (moisture). This means humidity is exchanged along with temperature — outgoing humid air transfers moisture to dry incoming air in summer, and vice versa in winter.
Which to Choose
In humid climates or applications like indoor pools and commercial kitchens, ERV systems are preferable because they help manage moisture loads. In dry climates or applications where moisture transfer is undesirable (laboratories, hospitals), HRV is the better choice. For most commercial office and retail applications in temperate climates, either system works well.
