HRV stands for Heat Recovery Ventilation. HRV works by removing stagnant air from a room that has higher humidity. It is commonly used in rooms that accommodate many rooms. It gives fresh outdoor air into the atmosphere. The heat recovery warms the incoming fresh air as the state air is expelled.
ERV stands for Energy Recovery Ventilation works similarly. It is commonly used in a cooler environment where there is no much humidity. The energy recovery recovers heat. It recuperates energy that is trapped in humidity. In summer, the humidity transfer works in reverse. The humidity in outdoor air is removed before it is allowed into the room.
If you are not familiar with what HRV and ERV are, these are known to be devices that are similar to each other. They are meant to make sure that the home will have fresh air. You have to admit that homes may sometimes have stale air inside the house, especially if it has not been used for a long time.
The only difference between the two is that HRV can only transfer heat while ERV will be okay in transferring not only heat but also moisture. There are some people who would need both heat and moisture so that they will be more comfortable inside their own homes.