Maintaining healthy indoor air quality is essential for building comfort, safety, and energy efficiency. An Energy Recovery Ventilator (ERV) brings fresh air into a building while capturing a significant portion of the heating or cooling energy that would normally be lost.
Here’s a simple breakdown of ERV fundamentals.
Why Energy Recovery Matters
Commercial buildings are required to bring in a specific amount of fresh outdoor air. For example:
- A 4-ton rooftop unit may require 25% fresh air, equal to about 400 CFM.
- That same 400 CFM of indoor air must be exhausted to maintain balanced pressure.
On a freezing day, that means pulling in 0°F air and throwing away 70°F air that you already paid to heat. Without recovery, the HVAC system has to work harder to maintain indoor temperature—raising energy costs.
An ERV solves this by capturing energy from the outgoing airstream before it leaves the building.
How an ERV Works
An ERV contains either:
- A rotating energy wheel
- A fixed, stationary core
Both designs move two airstreams in opposite directions—fresh outdoor air and stale indoor air—through a heat-exchange section.
Although completely separate, the airstreams pass close enough that heat and moisture transfer between them. The result:
- Outdoor air is preheated in winter
- Outdoor air is precooled and dried in summer
- Indoor air leaves the building while giving up its energy
This pro