Insulation standards and our ability to create airtight homes have increased greatly over the past 20 years. These changes have enabled us to create homes which are significantly more energy efficient than the homes of the past. Previously, excess moisture and fresh air could leave or enter the home thorough cracks or spaces where the insulation was lacking. Now that insulation techniques and standards have grown, the problem has shifted from energy loss, into an inability for the home to breathe. This can cause a feeling of stuffiness, too much moisture in the home, and increased allergens. An ERV or HRV exchanges old, stale air in the home out for fresh air. While slightly varied in what each type offers, either system is designed to elevate your comfort and alleviate air flow issues in the home.