What is the main difference between HRVs and ERVs?

The main difference between Heat Recovery Ventilators (HRVs) and Energy Recovery Ventilators (ERVs) lies in their function regarding heat and moisture exchange. HRVs are designed to transfer heat from the outgoing stale air to the incoming fresh air; however, they do not manage humidity levels. This means that in a dry climate, an HRV can effectively use the heat from the exhaust air to warm the incoming air without affecting moisture levels.

On the other hand, ERVs take the function of HRVs a step further by also transferring some moisture along with heat. This is particularly beneficial for maintaining balanced humidity levels in both warm and cold environments. When the air is humid, ERVs can remove excess moisture from the outgoing air to the incoming air, effectively helping to maintain a comfortable indoor humidity level. Conversely, in cold and dry climates, they can help retain moisture, preventing overly dry indoor conditions.

This difference is essential for understanding how these systems operate and their influence on indoor air quality and comfort in different climates. Understanding the distinction helps in selecting the right system for specific ventilation needs based on environmental conditions.