Heat Recovery Standards & Glossary
The reference sheet engineers reach for: the standards that define performance, the formulas behind every sizing, and the terms you see on a datasheet.
Standards quick-reference
| Standard | Scope | What it defines |
|---|---|---|
| EN 308 | EU test method for air-to-air heat recovery devices | Sensible & total heat-transfer rate and effectiveness test setup and procedure. |
| AHRI 1060 | Performance rating of air-to-air exchangers for ERV/HRV equipment | Sensible, latent and enthalpy effectiveness ratings at rated conditions. |
| ASHRAE Std 84 | Method of testing air-to-air heat exchangers | Laboratory procedure for sensible and total effectiveness. |
| EN 13141-4 | Residential ventilation components — performance testing | Field/lab test of heat-recovery ventilation units including effectiveness. |
| Eurovent 6/11 | European certification of air handling & heat-recovery units | Voluntary performance certification and energy labelling. |
| EN 16798 / EPBD | Building energy performance — ventilation requirements | Indoor environment and energy criteria that drive recovery specifications. |
Formulas engineers use
Sensible effectiveness εs = (Tsupply,out − Toutdoor) / (Tindoor − Toutdoor)
Total / enthalpy effectiveness εt = (hsupply,out − houtdoor) / (hindoor − houtdoor)
Recovered heating power Q = ρ · V̇ · cp · ΔT (ρ=1.2 kg/m³, cp=1.006 kJ/kg·K)
Dew point (Magnus) α = ln(RH/100) + 17.625·T/(243.04+T) ; Td = 243.04·α/(17.625 − α)
Run the numbers: Unit converter · Frost estimator
Glossary
- Sensible effectiveness
- Fraction of the temperature difference recovered; heat only, no moisture transfer.
- Total / enthalpy effectiveness
- Fraction of the enthalpy (heat + moisture) difference recovered; defines ERV performance.
- Rotary wheel
- Revolving thermal mass that transfers heat (and moisture, if enthalpy) between streams; highest effectiveness, small carry-over.
- Plate core
- Fixed stack of plates. Counter-flow reaches higher effectiveness than cross-flow; streams stay fully separated.
- Heat pipe
- Sealed pipe with phase-change fluid; passive, no motor, compact and freeze-tolerant.
- Run-around coil
- Two coils linked by a circulating fluid; separates streams by distance with no air mixing.
- Dew point
- Temperature at which air condenses moisture; below it, surfaces wet or (if <0°C) frost.
- Frost / defrost
- Ice forming on the cold side in winter; managed by preheat, bypass or frost-tolerant cores.
- Bypass
- Damper route that lets air skip the core in mild weather or during defrost.
- NTU
- Number of transfer units — dimensionless size of the exchanger; higher NTU means higher effectiveness.
- Face velocity
- Air speed through the core face; higher speeds cut size but raise pressure drop.
- Pressure drop
- Fan energy needed to push air through the core; trades off against effectiveness.
- ERV vs HRV
- HRV = heat only; ERV = heat + moisture. ERV controls humidity load, HRV avoids moisture transfer.
- Cross-contamination
- Exhaust leaking into supply; eliminated by separated cores (plate, heat pipe, run-around).
- Balanced flow
- Equal supply and exhaust airflow; unbalanced designs recover on the lower flow.
Translating specs into a build?
Send your duty — airflow, temperatures, humidity and exhaust description — and we will match a core to EN 308 / AHRI 1060 and your pressure budget.
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