Analysis and recommendations for operation of energy recovery ventilators (ERV) during pandemics

Energy Recovery Ventilators (ERVs) are integral to enhancing the energy efficiency of HVAC systems. However, during pandemics, guidelines often recommend bypassing or restricting ERV operation due to concerns about potential pathogen transmission between air streams, which could facilitate disease spread. While this approach addresses health concerns, it conflicts with the sustainable operation of HVAC systems due to their increasing energy demand. The effect of ERV operation or bypassing on disease transmission rates has not been systematically studied. Therefore, the present study aims to quantify the impact of operating versus bypassing the ERV on indoor disease transmission rates. Two bypassing scenarios are considered: (i) bypassing the ERV without altering the ventilation rate and (ii) bypassing the ERV with reduced ventilation to maintain thermal comfort. A medium-sized office building is modeled with an infected occupant in one room and noninfected occupants in connected rooms. The results demonstrate that certain pandemic-related guidelines, such as bypassing ERVs, may increase infection risks when HVAC systems are unable to compensate for the additional load. This highlights the need to reconsider recommendations on the use of ERV during pandemics. The study’s primary contribution is to clarify the role of ERVs in airborne disease transmission and provide evidence-based recommendations for their operation in future pandemics.