Ventilation Units / Energy Recovery Ventilators (ERV) / Buying Guide

Energy Recovery Ventilators (ERV): Buying and Selection Guide

This guide helps select sensible and potentially latent energy recovery 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

Select the energy exchanger and understand its latent transfer capability. 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 total effectiveness separately from sensible-only efficiency. 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 moisture management and high-humidity climate suitability. 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

Verify cross-leakage, exhaust contamination transfer and purge controls. 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

Check fan curves, external static pressure and outdoor-air rate. 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

Assess frost strategy, filters, access and control demand. 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: ERV is not proof that the unit will dehumidify a building under all conditions.

  • 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.