The short answer is because they get dirty over time and they have the potential to contain large amounts of dust and particulates. These systems were originally designed to make tighter, more energy efficient built homes healthier by removing stale dirty air and bringing in clean fresh air. If neglected, the HRV has the opposite effect. Home inspections often reveal that HRV’s are often neglected because people don’t understand how they work. Contaminants are trapped in the filters and ductwork causing it to work harder and shorten the life of your system. When an HVAC system is clean, it doesn’t have to work as hard to maintain the temperature you desire. As a result, less energy is used, leading to improved cost-effectiveness. Through normal occupation in a building, we generate a great deal of contaminants and air pollutants, such as dander, dust, and moisture. These contaminants are pulled into the HVAC system and re-circulated throughout the home. This re-circulation causes a build-up of contaminants in the duct work contributing to larger health issues. Whether you do it yourself, or rely on a professional, a very important part of your furnace upkeep involves ensuring that critical components are cleaned regularly. If you think about it, the main reason to change the oil in your car’s engines is because it becomes “polluted” with dirt.
