Greenhouse Air Exchange Time Calculator

Greenhouse Air Exchange Time assumption to check

Short-circuiting and restrictions lengthen effective exchange time.

A zero Fan airflow leaves ideal exchange time undefined in Greenhouse Air Exchange Time.

Greenhouse volume and the other inputs

Prepare Greenhouse volume and Fan airflow for Greenhouse Air Exchange Time. Keep unrelated records separate.

• Greenhouse volume. Default in Greenhouse Air Exchange Time: 6,000 cu ft.
• Fan airflow. Default in Greenhouse Air Exchange Time: 3,000 CFM.

Applying the ideal exchange time result

Recalculate after changing a covering, setpoint, ventilation rate, crop load, or equipment capacity.

Arithmetic used for Greenhouse Air Exchange Time

For ideal exchange time, the denominator comes from Greenhouse volume and Fan airflow.

For the prefilled measurements—greenhouse volume at 6,000 cu ft and fan airflow at 3,000 CFM—the calculated answer is 2.00 min. Use the Cold Frame Temperature Margin tool when temperature margin needs its own calculation.

Using the Greenhouse Air Exchange Time result

The calculator reports ideal exchange time first. A fair comparison requires the same unit convention in each case.

Greenhouse Air Exchange Time record to keep

Store the Greenhouse Air Exchange Time date, Greenhouse volume and Fan airflow, and Ideal exchange time.

Separate measured greenhouse volume from an assumed value so a later user can reconstruct the case.

Add the garden outcome as a new entry, using the same units and definition as ideal exchange time. Compare this result with Transplant Harvest Day Calculator when estimated harvest day is also needed.

What changes when greenhouse volume changes

A ten-percent test change in Greenhouse volume replaces 6,000 cu ft with 6,600 cu ft. Under the remaining sample values, ideal exchange time changes from 2.00 min to 2.20 min.

Only greenhouse volume changes in this Greenhouse Air Exchange Time example, making its numerical effect visible.

Keep the original ideal exchange time and the test result as separate scenarios.

Ideal exchange time questions