Heat Recovery Ventilation (HRV) and Energy Recovery Ventilation (ERV) are often used as if interchangeable. The difference is what they recover: an HRV moves only sensible heat, while an ERV (also called an enthalpy recovery ventilator) moves both heat and moisture.
What each transfers
| HRV | ERV | |
|---|---|---|
| Sensible heat (temperature) | Yes | Yes |
| Latent heat (moisture) | No | Yes |
| Best climate | Cold, dry winters | Mixed / humid |
| Humidity control | None | Active (both directions) |
| Typical core | Sensible plate or heat pipe | Enthalpy wheel or membrane plate |
Cold, dry climates
In a cold dry winter, indoor air is warm and humid relative to outside. An HRV retains that humidity (good) while recovering heat. An ERV would also transfer some moisture outward, which can be acceptable but is less necessary.
Humid summers
In a humid summer, an ERV rejects incoming moisture to the exhaust stream, cutting the cooling and dehumidification load. An HRV recovers only temperature, so the AHU must remove all incoming humidity mechanically.
How to decide
If your design goal is moisture control or you operate in a humid climate, specify an ERV. If you only need to cut heating load in a dry climate, an HRV is simpler and cheaper.
How the Two Approaches Differ
When evaluating options for HRV vs ERV: Sensible vs Total Energy Recovery, the main differences are recovery efficiency, first cost, footprint, and how the air streams are handled. A plate exchanger keeps the streams fully separate and is simple, while a rotary wheel can reach higher recovery but allows a small carryover of moisture and a trace of exhaust into the supply. Air-to-water systems shift energy into a water loop instead of directly into the supply air, which suits buildings with a hydronic heating or cooling network.
Efficiency and Cost
Plate units typically recover 50 to 65 percent of sensible heat at modest cost and with low maintenance. Rotary wheels reach 70 to 85 percent including latent recovery, at a higher price and with moving parts. Air-to-water versions trade some efficiency for flexibility in where the energy is used. The best value depends on energy prices, run hours, and whether humidity control is part of the requirement.
Which to Choose
Choose a plate exchanger for clean, cost-sensitive duties; a rotary wheel when maximum recovery or latent heat matters; and an air-to-water system when the recovered energy must serve another loop. Always size from measured airflow and temperature data rather than nameplate guesses, because oversizing wastes money and undersizing limits savings.
Frequently Asked Questions
Is higher recovery always better? Not always; beyond a point the extra cost outweighs the marginal energy saved. Do rotating parts need service? Yes, the wheel seal and drive should be checked periodically.