Heat Recovery Effectiveness Test Standards

“Effectiveness” is the number every code and rating system quotes, but the value only means something if the test method is stated. This article maps the main heat recovery effectiveness test standards and how they define the metric.

Definitions

• Efficacité sensible η_s = (T_supply − T_outdoor) / (T_extract − T_outdoor).
• Enthalpy (total) effectiveness η_t = (h_supply − h_outdoor) / (h_extract − h_outdoor), using moist-air enthalpy.
• Latent effectiveness uses humidity ratio in place of enthalpy.

The Standards

Standard	Scope
EN 308	Test procedures for air-to-air and flue-gas heat recovery devices (sensible and latent).
EN 13053	Rating and performance of air-handling units, including heat recovery sections and pressure drop.
EN 13141-7	Performance testing of residential mechanical supply/exhaust ventilation units.
AHRI 1060 / 1061	Energy recovery ventilators — the method ASHRAE 90.1 references for its 50% minimum.

Why the Method Matters

• Test conditions differ: Ecodesign measures η_t at −10 °C, 0 °C, and +10 °C outdoor; ASHRAE uses design heating and cooling conditions.
• A wheel rated 75% by AHRI 1060 may read differently under EN 308 because of how leakage and frost are handled.
• Pressure drop is part of the story — a more effective core that needs a bigger fan can erase the saving, which is why Ecodesign SFP limits bind efficiency and fan power together.

Picking a Device Against the Numbers

Use the measured η_t from the relevant standard when checking code floors. For non-rotating critical ventilation, compare a membrane core against a wheel on the same test basis, and fold the pressure drop into the AHU selection calculation.

Questions fréquemment posées

What is sensible effectiveness?
The ratio of temperature change delivered to the supply air versus the temperature difference between extract and outdoor air.

What is enthalpy effectiveness?
The same ratio using moist-air enthalpy, capturing both temperature and humidity recovery.

Which standards govern recovery testing?
EN 308, EN 13053, and EN 13141-7 in Europe, and AHRI 1060 and 1061 referenced by ASHRAE 90.1.

Why does the test method matter?
Different standards use different conditions and treat leakage and frost differently, so the same device can read differently, and pressure drop must also be considered.

Questions fréquemment posées

What is sensible effectiveness?

The ratio of temperature change delivered to the supply air versus the temperature difference between extract and outdoor air.

What is enthalpy effectiveness?

The same ratio using moist-air enthalpy, capturing both temperature and humidity recovery.

Which standards govern recovery testing?

EN 308, EN 13053, and EN 13141-7 in Europe, and AHRI 1060 and 1061 referenced by ASHRAE 90.1.

Why does the test method matter?

Different standards use different conditions and treat leakage and frost differently, so the same device can read differently, and pressure drop must also be considered.