Beyond SRE: Understanding Real-World Performance of Balanced Ventilation Systems

Comfort

In Part One, we explored why Sensible Recovery Efficiency (SRE) alone doesn’t provide the full picture when comparing heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs). While key metrics like SRE, TRE, and fan efficacy are critical, understanding how these numbers translate to actual in-field performance can be challenging. In this follow-up article, we dig deeper into real-world data and testing results to reveal what the numbers really say — helping engineers, contractors, and specifiers make informed decisions that optimize comfort, energy efficiency, and indoor air quality.

Did you Miss Part 1?

Learn which certified metrics truly reflect real-world performance.

Read Part 1

A Real-World Comparison: A Closer Look at Tested Performance

At a glance, many energy recovery ventilators (ERVs) may seem similar, especially when product specs list comparable airflow and recovery values. But deeper inspection of testing standards, certification status, and performance under specific conditions often reveals meaningful differences.

Consider the Fantech HERO 100E, competitor Model A, and competitor Model B. While each product claims strong performance, only two are HVI certified, and their test results diverge in ways that can significantly affect system design, particularly in extreme climates or code-driven applications.

Attribute	HERO 100E	Model A	Model B
HVI Certified	Yes	Yes	No
Net Supply @ 0.4” w.g.	102 CFM	144 CFM	112 CFM
Maximum Sensible Recovery Efficiency @ 0°C/32°F	77% at 70 CFM	75% at 89 CFM	74% at 64 CFM
Maximum Sensible Recovery Efficiency at 25°C/-13°F	60% at 70 CFM	65% at 78 CFM	Not Rated at 25°C/-13°F
Maximum Total Recovery Efficiency at 35°C/95°F	70% at 42 CFM	49% at 83 CFM	48% at 66 CFM
Maximum Fan Efficacy	1.2 CFM/W	1.1 CFM/W	1.1 CFM/W
ENERGY STAR® Certified	Yes	No	No
Drainless	Yes	Yes	Undisclosed
Electronic balancing	Yes	No	No

Certified vs. Self-Declared Data:

Both the HERO 100E and Model A are HVI certified, meaning their performance ratings are independently tested and verified. Model B, on the other hand, is not HVI certified; its ratings are self-declared and unverified by a third party. For engineers focused on code compliance or evidence-based design, this can be a critical differentiator.

Cold Climate Performance:

The HERO 100E and Model A both report Sensible Recovery Efficiency (SRE) at -13°F (-25°C), a critical benchmark for northern markets. Model A leads slightly in this metric, 65% at 78 cfm vs. the HERO’s 60% at 70 cfm, indicating stronger sensible heat recovery in very cold weather. However, Model B may be suitable for this weather, but its performance and reliability would remain unknown until a complaint from the homeowner is made.

Fan Efficacy and Energy Use:

The HERO 100E also posts the best fan efficacy among the three models at 1.2 cfm/W, meaning it delivers more airflow per watt consumed. Model A and Model B both reach 1.1 cfm/W but fall short of the HERO’s energy performance. Only the HERO is ENERGY STAR® certified, meeting strict guidelines for energy efficiency.

Note: This product has earned the ENERGY STAR® designation by meeting rigorous energy efficiency standards set by Natural Resources Canada and the U.S. EPA. It qualifies for ENERGY STAR® certification when used in Canada.

Design Features:

In terms of ease of commissioning and installation, the HERO 100E includes electronic balancing, absent in both Model A and Model B, and is drainless by design. These practical features simplify setup and maintenance, saving time on the job site.

If peak sensible recovery at extreme cold is the top priority, Model A may edge ahead. If third-party certification, high fan efficacy, and simple installation are prioritized, the HERO 100E could be considered over Model A and model B.

Fantech’s Approach to Transparent Performance Data

Fantech is committed to publishing detailed and transparent performance data to support engineers, energy modelers, and HVAC professionals. Our residential ventilation systems are:

Tested to CSA C439
Certified through HVI
Fully documented for SRE, TRE, latent recovery and fan efficacy

We believe in specifying products based on verified performance, not just manufacturer claims.

Key Considerations for Engineers and Contractors:

Selecting the right residential HRV or ERV goes beyond scanning a spec sheet. While products may appear similar on paper, meaningful performance differences often emerge when tested under standardized conditions. Here are a few best practices to guide accurate system selection:

Verify Product certification

Always ensure you're comparing equipment that is HVI certified. This guarantees that the product has been tested and rated in accordance with CSA C439 and that HVI ensures consistency and reliability across performance data.

Confirm Operating Conditions

Compare airflow and efficiency at equivalent external static pressures and ambient temperatures when possible. Performance values reported at different conditions can distort real-world expectations.

Look Beyond SRE

While Sensible Recovery Efficiency (SRE) is critical, also check for Total Recovery Efficiency (TRE) when selecting a unit for warm and humid climates. Fan efficacy is also a key performance indicator and is often regulated. These metrics offer deeper insight into comfort, humidity control, and energy use when designing and selecting a ventilation system.

Use Third-Party Data

When two products report similar SREs, third-party verification matters. Use the HVI Certified Products Directory to validate that the published data is independently confirmed and reflects tested performance.

The Cost of Inaccurate Comparisons

Misreading or oversimplifying ERV/HRV performance data can lead to more than just inefficient choices; it can compromise the success of a project.

For Specifying Engineers:

Energy modeling errors
Using inaccurate input data can skew heating and cooling load calculations, affecting system sizing and operational cost projections.

Missed ventilation targets
Selecting a unit based on overstated airflow or recovery performance may result in insufficient fresh air delivery, especially under design conditions.

Discomfort or moisture issues in the home
Overlooking latent recovery or system capacity can lead to humidity buildup or drafts, compromising occupant comfort.

Non-compliance with codes or energy programs
Performance shortfalls can jeopardize compliance with building codes, ENERGY STAR, or other green building certifications.

For Contractors:

Underperforming systems lead to callbacks
Systems that don’t meet expectations in the field can trigger costly return visits, adjustments, or even replacements.

Customer dissatisfaction
Occupants may notice discomfort or humidity problems, leading to negative reviews or damaged trust.

Installation mismatches
Systems chosen without a complete understanding of their performance under the project’s specific conditions might require unexpected adjustments, delay completion and increasing labor costs.

Ask the Right Questions, Get the Right Performance

The next time two HRVs or ERVs seem comparable on paper, dig deeper. Ask: Are both HVI certified? Are the SRE, TRE, and fan efficacy (plus other key metrics) reported in the same conditions?

By relying on standardized, third-party-certified data and a comprehensive suite of performance metrics, rather than just a single headline number, engineers and contractors can make smarter, more informed choices. When it comes to designing high-performance ventilation systems, knowing how to interpret the data is just as important as the data itself.

Resources

CSA Group. C439-09 – Rating the Performance of Heat/Energy-Recovery Ventilators.

HVI. Certified Product Directory. https://www.hvicertified.org

AHRI. Standard 1060 – Performance Rating of Air-to-Air Heat Exchangers for Energy Recovery Ventilation Equipment. https://www.ahrinet.org

ENERGY STAR. https://www.energystar.gov