“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 Sensible effectiveness ηs = (Tsupply − Toutdoor) / (Textract − Toutdoor). Enthalpy (total) effectiveness ηt = […]
LEED Energy Recovery Credit
Energy recovery contributes to the Energy & Atmosphere (EA) credits that dominate LEED scoring. Whether you register under LEED v4.1 (still open in 2026) or the newer LEED v5 (2025–2030 cycle), ventilation recovery reduces the modeled energy use that the credit is scored on. LEED v4.1 BD+C EA Credit: Optimize Energy Performance is worth up […]
ISO 50001 and Heat Recovery
ISO 50001:2018, confirmed in 2024 and updated by Amendment 1:2024 (climate-action wording), is the international standard for an Energy Management System (EnMS). It does not prescribe technologies, but its structure makes heat recovery a natural “significant energy use” to control and measure. The EnMS Cycle ISO 50001 follows Plan-Do-Check-Act: Energy review — map energy sources, […]
EU EPBD and Zero-Emission Buildings
The revised Energy Performance of Buildings Directive (EU) 2024/1275 — the EPBD — entered into force on 28 May 2024, with Member States required to transpose it into national law by 29 May 2026. It raises the bar from nearly-zero-energy to zero-emission buildings and makes heat recovery central to compliance. Key Dates Milestone Date Directive […]
EU Ecodesign Requirements for Ventilation Units
The European Union regulates ventilation units through Regulation (EU) 1253/2014 (the “Ecodesign” Lot 21 measure). It sets binding minimum thermal efficiency and fan-power limits for units placed on the EU market, so any AHU or ERV sold in Europe must comply. Scope Applies to residential and non-residential ventilation units with a fan electric power of […]
ASHRAE 62.1 Ventilation and Energy Recovery
ASHRAE 62.1-2022 sets the minimum ventilation rates for acceptable indoor air quality, and its requirements directly drive how much outdoor air — and therefore how much recoverable energy — a system must handle. Energy recovery is the bridge between good ventilation and reasonable energy bills. The Ventilation Rate Procedure Section 6.2 uses the Ventilation Rate […]
ASHRAE 90.1 Heat Recovery Requirements
ASHRAE Standard 90.1 is the reference energy standard for commercial buildings in the United States, and its exhaust-air energy recovery rule is the single most common code trigger for specifying a heat recovery ventilator. This article summarizes the ASHRAE 90.1-2022 requirements that apply to designers specifying air-to-air recovery. When Recovery Is Mandatory (Section 6.5.6.1) A […]