HRV and ERV: Choose the Right Ventilation System for Your Home

August 11, 2015

Climate is a major consideration when choosing between a HRV and ERV. Since the Des Moines area sees such a variety of weather, choosing the right ventilation system for your home isn't always obvious, but weighing a few additional factors helps.

What's the Difference? A heat-recovery ventilator (HRV) contains a heat exchanger that, in summer, draws heat from the hot incoming outdoor air and moves it into the outgoing air, reducing the amount of heat that enters your air conditioned home. In winter, it does the opposite to pre-heat incoming air. The difference between a HRV and energy-recovery ventilator (ERV) is that an ERV transfers moisture as well as heat.

Climate Considerations A HRV is usually recommended for cold-winter climates. An ERV is more often preferable in climates with hot, humid summers because they let less moisture into the house. In a mixed climate like ours, either system can work. The most important consideration is your home's humidity level.

Age and Airtightness Your home's age can influence this as well. Older homes were intentionally built with cracks to provide airflow. While this can increase humidity in summer, it tends to lower year-round humidity, even if the air leaks have been sealed. That means an ERV, which won't exacerbate winter dryness, is often a better choice for an older home. Modern homes are built for air tightness, which traps moisture indoors. If you enjoy long, hot showers, cook frequently or have a large house plant collection, high indoor humidity is even more likely. In these cases, HRVs typically work better.

Size and Occupancy People add moisture to the air simply by breathing. In a large home with few people, this won't affect the humidity much, so an ERV can work well. That's because a home like this is likely to dry out in winter, a problem an ERV can help prevent. If you've got a lot of people in a small house, though, installing an ERV will only contribute to high humidity levels in winter. Need help deciding between an HRV and ERV? Contact us at for more information on air conditioner maintenance at Lozier Heating & Cooling in the Des Moines area. Our goal is to help educate our customers in the greater Des Moines, Iowa area about energy and home comfort issues (specific to HVAC systems). Credit/Copyright Attribution: "Jennifer Gottschalk/Shutterstock"