Formula & worked example
εs=(Ts−To)/(Ti−To); Qs=ṁcpεs(Ti−To); Ql=ṁhfgεl(Wi−Wo).
At 1 kg/s, 70% sensible effectiveness and a 20 K indoor-outdoor difference recovers about 14.1 kW sensible heat.
HVAC engineering calculator · Updated Sep 17, 2026
ERV Effectiveness Calculator — Sensible, Latent & Recovered Load
Estimate sensible and latent energy-recovery effectiveness, supply leaving conditions and recovered sensible/latent load from airflow and indoor/outdoor states.
Inputs
Live result
Supply leaving temperature 27.3 °C
Supply leaving humidity ratio 0.0132 kg/kg
Recovered sensible load -7.7462 kW
Recovered latent load -11.76 kW
Recovered total -19.5062 kW
Assumptions & limits
- Balanced-flow effectiveness model.
- Humidity ratio must be supplied explicitly; frost/defrost and leakage are not modeled.
Frequently asked questions
What does this ERV Effectiveness Calculator calculate?
Estimate sensible and latent energy-recovery effectiveness, supply leaving conditions and recovered sensible/latent load from airflow and indoor/outdoor states.
Is this suitable for final equipment selection?
Use it as an auditable engineering cross-check. Final selections should use measured design conditions, manufacturer data, applicable standards and local code.
Why does MAXScanner expose the assumptions?
HVAC shortcuts can hide density, pressure, concentration and effectiveness assumptions. Exposing them makes the result easier to verify and revise.