The frequency of air exchanger cleaning depends on several factors, including the type of air exchanger you have, the level of use, and the presence of pets or other sources of contaminants in your home. Here are some general guidelines for how often to clean your air exchanger: For a standard air exchanger, it is generally recommended to have it cleaned every 2-3 years. If you have a heat recovery ventilator (HRV), it is generally recommended to have it cleaned every 1-2 years. If you have pets or live in an area with high levels of outdoor air pollution, it may be necessary to clean your air exchanger more frequently. If you notice an unusual increase in dust or other contaminants in your home, it may be time to clean your air exchanger. It is important to note that these are general guidelines and the actual frequency of cleaning may vary based on your specific circumstances. It is always a good idea to consult with a professional HVAC technician to determine the best cleaning schedule for your air exchanger.