What the Calculator Does

The sizing calculator turns four inputs into recovered power, effectiveness, and payback: supply airflow, exhaust airflow, indoor and outdoor temperatures, and run hours.

Inputs You Need

• Supply and exhaust airflow in m3/h or cfm
• Outdoor winter and summer design temperatures
• Indoor setpoint and allowable supply-air temperature
• Electricity price and annual operating hours

How It Computes

Recovered power Q = m_dot x cp x DeltaT x effectiveness. The tool then multiplies by run hours and price to show annual saving and simple payback.

Using It Well

• Enter part-load average airflow, not peak, for realistic savings
• Add the extra fan energy from pressure drop
• Compare plate, rotary, and heat pipe side by side

Verify

Treat calculator output as a screen; confirm the final choice against an EN 308 or AHRI 1060 rating at the operating point.