HVAC systems operate by taking air from the outdoors, conditioning it (heating, cooling humidifying/dehumidifying) and blowing it indoors. Pretty simple and straight forward in concept, but potentially expensive depending on where you live and the time of year.
One of the issues with the basic design is that all the incoming air needs to be modified by the system to the requirements for the indoor air. It needs to be filtered, heated or cooled, and it needs to have moisture added or removed which is quite a bit of work. An ERV (Energy Recovery Ventilator) is an add-on system for your HVAC unit that preconditions incoming air using the stored energy in exhaust air. In order to maintain building pressure, air is expelled as new air is drawn into a building. This expelled air has already been treated. The ERV utilizes the energy in this exhaust air to condition incoming air, making it closer to the required conditions. This means the HVAC system has less to do. This translates into significant savings.
A typical ERV system recovers over 50% of the energy in the air leaving the system. This energy is used to condition the incoming air temperature and humidity. Since the HVAC system is starting with air closer to its goal, it has less work to do.
The nice thing about ERV units is that they can often be added to existing HVAC systems allowing you to reap the savings without a huge financial outlay.
