• The application of HRVs obviously depends upon the initial radon readings, but also the climate and the cost of energy for a particular building.
  
  
• Note that HRVs can also be used in warm climates where an energy savings can be demonstrated. In this case, the cooling degree days would be used.

Common Failure Modes for HRVs

• Inlet screen clogs with dirt and debris thus decreasing air supply, while exhaust is still drawing air from basement. This condition can increase radon entry and certainly create a backdraft potential.

  Recommend frequent cleaning and install a differential pressure switch between supply and return with warning light or alarm.

• HRV ices up due to retention of condensation on heat transfer media, which can then freeze.
  
  Can break rotating mechanism on rotating wheel style. Install defrost controls on units in cold climates.

Copyright 2000, Great Lakes Center for Occupational & Environmental Safety & Health, School of Public Health, University of Illinois at Chicago