If you own a newer home, chances are that it is equipped with an air-to-air exchanger. Newer homes are constructed to meet higher efficiency standards, meaning they are more airtight and have little or no air infiltration. Your air-to-air exchanger helps keep indoor air clean and healthy. Quite often, our HomePro Inspections home inspectors find that this piece of equipment is overlooked and poorly maintained.
Air-to-air exchanger
Is Your Air-to-Air Exchanger an HRV or an ERV?
There are two common types of air-to-air exchangers. One is a heat recovery ventilator (HRV), and the other is an energy recovery ventilator (ERV).
An HRV recovers heat only, while an ERV recovers heat and has the ability to remove moisture from your home's interior. HRVs are generally more common in the northern part of the country, where the winters are cold and dry. ERVs are more common in the south, where it is more humid.
How do air-to-air exchangers work?
The function of an air-to-air exchanger is simple. The system works by using two fans; one fan draws the air from the home's inside and releases it outside. The other fan draws air from the outside and releases it inside your home.
The air from the two fans passes through a central core in the air-to-air exchanger. This core is comprised of a series of narrow passages that alternate directions, allowing the inside and outside air to pass by each other. Heat is transferred between the passages, while the air streams are not allowed to mix with each other.
For example, in the winter, the warm, stale air from inside your home passes through the heat exchanger core in one direction, while the cold air from the outside passes through in the other direction. The warm air warms the cold air as it passes through the heat exchanger core. Any excess moisture will condense on the core and drip into a tray at the bottom of the unit. A drain tube is routed to a drain.
Maintaining your air-to-air exchanger is important.
Most air-to-air exchangers have their recommended cleaning and maintenance printed somewhere on the system, typically on the core or inside cover.
Filters: Dirty and clogged filters lower the efficiency of your air-to-air exchanger, resulting in restricted airflow. It also makes the fans work harder and uses more electricity to move the air through the system.
Dirty filter at the exchanger core
Filters should be cleaned or replaced per the manufacturer's instructions, typically every 2 to 3 months. The filters can be pulled from the unit and vacuumed to remove dust and debris. You can also soak the filters in warm, soapy water and then rinse them clean. Let them dry before returning them to the unit.
Heat exchanger core: Refer to the owner’s manual for specifics on cleaning the core. The core can be removed from the unit for cleaning. In most cases, vacuuming the core or using compressed air to blow any debris from the core is sufficient. You can also soak it in warm, soapy water and then rinse it clean. Let the core dry before returning it to the unit.
Condensate tray and drain: If your air-to-air exchanger has a condensate tray and drain, it will be located at the bottom of the unit. Clean up any debris or deposits using warm, soapy water, and rinse. Check to see that the drain hose is free from debris and that it drains freely to a drain.
Ducts and interior: Vacuum any debris from the ducts and interior of the unit. Wipe surfaces with a warm, damp cloth.
Fans: Remove any accumulated dirt or debris by gently brushing the fan with a soft brush.
Outdoor intake and exhaust vents: Remove any obstructions that may be blocking the intake and exhaust vents. What we generally find is wasp or hornet nests, leaves, or just ambient dust and debris. Don’t forget that frost and snow can build up during the winter months. It is important that your air-to-air exchanger has adequate airflow into and out of the unit.
Dust and debris at the air-to-air inlet duct
Summary
When operating correctly, the air-to-air exchanger in your home will keep your indoor air clean and healthy. Keeping it maintained is easy and takes little time. During the course of a home inspection, our home inspectors find, more often than not, that this piece of equipment is not maintained. The result is poor indoor air quality and higher operating costs.
At HomePro Inspections, our home inspectors are trained to inspect all areas of the home. We inspect air-to-air exchangers to see that they are maintained and that they appear to be operating correctly. Any issues found are documented in your home inspection report and recommended for resolution by yourself or a qualified professional.
Visit our website to learn more or to schedule your home inspection in the Rochester, Owatonna, and Faribault, MN areas. You can contact us today at (507) 202-8942 or use our online “Schedule Now” feature to schedule an appointment.