This article provides the basics on energy recovery ventilators (ERVs): what they are, what they do, how they are installed, and service recommendations.

Airflow (cfm) and apparent sensible effectiveness (ASE) are the major features of an ERV. Often units will also offer filters, controls, drain, defrost, etc. Don’t get too caught up in available options, though. An ERV works best when operated constantly. The moisture transfer keeps the core above dewpoint temperatures, preventing the core from freezing in all but the most extreme conditions. And filtering only a small amount of the air in the home will not replace a good whole house air cleaner.