An HRV, or heat recovery ventilator, is a mechanical ventilation device that exchanges stale indoor air for fresh outdoor air while transferring heat, but not moisture, between the two air streams, recovering thermal energy that would otherwise be lost through simple exhaust ventilation alone.
This heat-only transfer, without the moisture exchange an ERV provides, makes HRVs particularly suited to cold, dry climates where retaining moisture indoors during heating season might not be desirable, or where preventing excessive humidity transfer specifically matters for the local climate conditions.
By recovering a significant portion of the energy that would otherwise be lost when exhausting conditioned indoor air and replacing it with unconditioned outdoor air, an HRV allows homes to achieve necessary ventilation with considerably less energy penalty than an unbalanced ventilation approach would incur.
What Does an HRV Involve?
- A core exchanging heat, but not moisture, between air streams
- Separate ducting for incoming and outgoing air
- Filtration for incoming fresh air
- Balanced airflow between exhaust and supply
Why Are HRVs Important?
The energy recovery capability an HRV provides makes achieving adequate whole-house ventilation considerably more energy-efficient than simple exhaust or supply-only ventilation, offering genuine value particularly in cold climates with significant heating demand where unrecovered ventilation losses would otherwise be substantial. This efficiency benefit has made HRVs increasingly standard in high-performance home construction, particularly in colder regions.
In climates where excessive indoor humidity isn’t typically a concern, or where preventing moisture transfer specifically matters, choosing an HRV over an ERV allows for effective ventilation heat recovery without introducing the additional moisture management considerations an ERV’s dual transfer capability would involve.
HRV vs. ERV
An HRV transfers only heat between air streams, often preferred in drier or colder climates. An ERV transfers both heat and moisture, well suited to humid climates where this additional exchange capability offers genuine benefit.