ERV/HRV Calculator

Energy Recovery Ventilator sizing and efficiency calculation

ERV vs HRV Selection

ERV (Enthalpy Recovery): Transfers both heat AND moisture. Best for humid climates and air-conditioned spaces.
HRV (Heat Recovery): Transfers only sensible heat. Best for dry/cold climates or spaces with high indoor humidity.

Space Information

Building Type

Floor Area

Number of Occupants

Leave blank for auto-estimate

Climate Conditions

Outdoor Temperature (Design)

Indoor Temperature (Setpoint)

°C

Outdoor Relative Humidity

Indoor Relative Humidity (Target)

ERV/HRV Specifications

Equipment Type

Sensible Efficiency

Latent Efficiency

Calculation Results

Required Fresh Air

CFM (- m³/h)

Sensible Recovery

Latent Recovery

Total Recovery

kW (- BTU/h)

Supply Air Conditions (After Heat Exchange)

Supply Temp: -

Supply RH: -

AC Load Reduction: -

Est. Annual Savings: -

Ventilation Standards Reference

Space Type	CFM/person	CFM/m²	Typical Density
Residential	7.5	0.06	1 person / 40m²
Office	5	0.06	1 person / 14m²
Classroom	10	0.12	1 person / 4m²
Retail/Shop	7.5	0.12	1 person / 6m²
Restaurant	7.5	0.18	1 person / 2m²
Gym/Fitness	20	0.06	1 person / 4.6m²
Hospital	25	0.06	1 person / 10m²

Reference: ASHRAE Standard 62.1-2022 / EN 16798

Typical ERV Efficiency

Sensible: 70-85%
Latent: 50-75%
Total: 65-80%

Energy Savings Potential

Cooling season: 20-40% load reduction
Heating season: 30-50% load reduction
Annual: 15-35% HVAC energy savings