A novel system for and method of balancing fresh air flow and exhaust air flow through a ventilator. The ventilator has an air-to-air heat exchanger operably mounted within a principal fresh air flow passage and a principal stale air flow passage. A flow meter is provided for connection to the principal fresh air flow passage and the principal stale air flow passage, across the air-to-air heat exchanger. The flow meter is proportionally responsive to mass flow of the air flow passages to which they are connected. Further involved is at least one damper within at least one of the air flow passages. To ensure that both air flow measurements indicate a substantially equal response, each damper can be adjusted to change the amount of air flow within its respective air flow passage.