Ventilation Units / Heat Recovery Ventilators (HRV) / Buying Guide

Heat Recovery Ventilators (HRV): Buying and Selection Guide

This guide helps select sensible heat recovery with balanced extract and outdoor air systems using installed ventilation requirements and whole-life operation, rather than a single heat-recovery percentage.

First step: Determine design supply and extract airflows and calculate real external static pressure, including ducts, terminals and progressively loaded filters.

1. Determine Outdoor Air Requirements

Size continuous supply and extract flow to occupancy and building ventilation requirements. Ask for certified airflow, recovery and acoustic data at comparable conditions. Regional regulations and climate design conditions can materially affect final selection.

2. Compare Recovery Type and Efficiency

Compare thermal efficiency on equivalent airflow, temperature and test conditions. Ask for certified airflow, recovery and acoustic data at comparable conditions. Regional regulations and climate design conditions can materially affect final selection.

3. Fan Duty, Pressure and Electrical Energy

Review fan static-pressure capability at actual duct and filter resistance. Ask for certified airflow, recovery and acoustic data at comparable conditions. Regional regulations and climate design conditions can materially affect final selection.

4. Moisture, Frost and Filtration

Account for frost protection and condensate drainage in winter climates. Ask for certified airflow, recovery and acoustic data at comparable conditions. Regional regulations and climate design conditions can materially affect final selection.

5. Installation, Noise and Access

Inspect acoustic limits, duct layout and serviceable filters. Ask for certified airflow, recovery and acoustic data at comparable conditions. Regional regulations and climate design conditions can materially affect final selection.

6. Controls, Balancing and Servicing

Plan outdoor and exhaust terminations, balancing and user control. Ask for certified airflow, recovery and acoustic data at comparable conditions. Regional regulations and climate design conditions can materially affect final selection.

7. Common Mistakes

Technical warning: HRVs transfer heat but do not necessarily transfer moisture like an enthalpy ERV.

  • Failing to allow filter pressure increase with use.
  • Assuming nominal laboratory recovery effectiveness applies to every installed airflow.
  • Ignoring winter condensation, condensate line maintenance or outdoor intake placement.
  • Using recirculating heating/cooling equipment as a substitute for outdoor air.

8. Pre-Order Checklist

  1. Design ventilation schedule, occupancy and area use.
  2. Outdoor air and extract balancing targets.
  3. Duct and equipment static pressure calculation.
  4. Fan energy, controls and actual recovery performance.
  5. Climatic frosting, moisture and bypass operation.
  6. Filter type and service interval.
  7. Noise, access, mounting and electrical supply.
  8. Commissioning, airflow balancing and maintenance handover.

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Standards and References

See ASHRAE 62.1 and 62.2 for ventilation context, along with regional requirements and the manufacturer’s heat-recovery, airflow and power curves.

AirAlign independent buying guide · October 2026. HVAC design and ventilation compliance are project-dependent.