Heat Recovery Tools & Calculators
Practical calculators for HVAC engineers, specifiers and buyers of air-to-air heat exchangers. All calculations run in your browser, no data leaves the page.
Sizing & Effectiveness
Energy & Cost Savings
Unit Converter
Which Type?
Sensible effectiveness es = (T_supply_out - T_outdoor) / (T_indoor - T_outdoor) | Recovered power Q = r*V*cp*dT (r=1.2 kg/m3, cp=1.006 kJ/kg*K)
Sensible effectiveness-
Temperature rise on supply-
Recovered heating power-
Annual energy (4000 h/yr)-
Balanced-flow assumption: supply and exhaust airflow are equal. For unbalanced flows use the lower airflow for both sides. Enthalpy (total) recovery is only possible with a rotary wheel or enthalpy plate, sensible plate/heat-pipe cores transfer no moisture.
Recovered power (avg)-
Annual energy recovered-
Annual cost saving-
CO2 avoided / year-
Simple payback-
Averages the recovered power across the heating season, real savings depend on your climate profile. Replace the price and CO2 factor with your local utility values.
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1 CFM = 1.699 m3/h, C = (F-32)*5/9, 1 kW = 3412 BTU/h, 1 Pa = 0.004014 in. w.g.
Yes, humidity control matters (pool, lab, humid climate)
No, sensible (temperature) recovery is enough
Yes, zero cross-contamination is required
No, streams may share the same building air
Max efficiency (up to 80-85%)
Compact footprint / easy retrofit
Lowest cost
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These tools give first-order estimates for screening and education. Final selection must follow the applicable standard (EN 308 / AHRI 1060) and your project airflow, pressure budget and local code. Read the heat-recovery guide