Energy Recovery Ventilation (ERV) systems play a crucial role in modern HVAC design. They improve indoor air quality, reduce HVAC loads, and enhance overall comfort—while meeting today’s more demanding ventilation codes and efficiency standards. Whether you’re a technician in the field, a project designer, or an HVAC professional looking for a quick refresher, this overview covers the essentials of ERV technology and why it matters.
What an ERV Is
An Energy Recovery Ventilator (ERV) is a specialized HVAC component designed to exchange energy between exhausted indoor air and incoming outdoor air. Instead of bringing in untreated outdoor air—and forcing the rooftop unit (RTU) to condition it from scratch—an ERV recovers heat and moisture during the ventilation process.
The result:
- Better indoor air quality
- Reduced HVAC operating costs
- Less strain on heating and cooling equipment
Why ERVs Are Needed
Modern buildings require fresh, clean outdoor air to maintain healthy indoor environments. However, conditioning that outside air can represent a major energy cost. ERVs solve this challenge by:
- Providing required outdoor air with minimal energy loss
- Helping facilities meet ventilation codes and ASHRAE standards
- Reducing the heating or cooling load on RTUs
- Stabilizing humidity levels
- Enhancing comfort for occupants
This makes ERVs especially valuable in high-ventilation environments where outside air requirements are significant.
Types of ERV Technologies
There are two primary ERV technologies used throughout the HVAC industry:
Fixed Plate/Core ERVs
- Utilize a stationary heat exchanger core
- Transfer heat and moisture between the supply and exhaust airstreams
- Have no moving parts, resulting in very low maintenance requirements
- Deliver proven, reliable performance
Energy Wheel ERVs
- Use a rotating wheel media to transfer energy
- Offer high-efficiency heat and moisture transfer
- Provide superior humidity control in challenging environments
Wheel ERVs are particularly effective in applications with large ventilation demands or where moisture recovery is critical.
How ERVs Work
The basic ERV process can be summarized in four steps:
- Stale indoor air is exhausted through the ERV.
- Fresh outdoor air enters the ERV at the same time.
- Energy (heat and moisture) is transferred between the two airstreams through a core or wheel.
- The incoming air is delivered to the space pre-conditioned, reducing the workload on the HVAC unit.
By transferring energy between airstreams, the ERV significantly lowers the amount of heating or cooling the RTU must perform.
Benefits of ERVs
ERV systems provide measurable advantages across performance, efficiency, and comfort:
- Lower operating costs due to reduced energy consumption
- Improved system efficiency
- Balanced humidity for better comfort
- Reduced strain on RTUs, extending equipment life
- Higher indoor air quality
- Less outside air conditioning, even during extreme temperatures
ERVs deliver a win-win combination of savings and comfort.
Applications
ERVs are used in nearly every type of commercial environment, including:
- Schools and universities
- Retail stores and supermarkets
- Office buildings and mixed-use spaces
- Healthcare facilities
- Environments with high outside air requirements
Wherever fresh air is needed, an ERV provides a cost-effective solution.
