Evidence brief: verifying greenhouse ventilation
Which measurements distinguish working equipment from effective heat and moisture management?
Scope of this review
Commercial greenhouses using vents, fans and heating. The review concerns airflow paths, moisture comparison and commissioning. It is not a ventilation design calculation or a crop-specific climate schedule.
How we assessed the evidence
Sources reviewed on 8 October 2026. We checked the original study or university guidance, separated its setting from transferable principles, and developed an operating checklist. This is an editorial review, not a systematic review or a Hamfy field trial. Worked examples use stated assumptions.
What the evidence supports
Installed airflow needs verification
Hamfy proposes documenting inlets, outlets, obstructions and actuator feedback before interpreting climate response. A catalogue rating or motor-on signal cannot establish performance in the crop zone.
Moisture and heat must be considered together
The worked humidity-ratio comparison demonstrates a physical possibility. It does not select a vent opening or account for transpiration and the building’s heat balance.
Control quality is an observable outcome
A commissioning record can compare gradients, excursions and recovery. Energy, crop quality and yield need their own measurements rather than being inferred from smoother sensor traces.
What this review does not establish
- University examples reflect their greenhouse geometry and climate; do not apply airflow rules without a design review.
- The psychrometric example assumes a common pressure and excludes ongoing moisture and heat sources.
- No measured energy saving, yield increase or Hamfy customer installation is claimed.
Hamfy’s proposed next step
Create a weather-aware operating sequence with the crop manager and designer, then test it with spatial measurements and actual actuator states. Use the findings to specify a focused equipment or control upgrade.
Evidence to collect for a real project
- Greenhouse geometry, crop layout, vent and fan specifications, and screen configuration.
- Synchronized indoor, outdoor and actuator records under representative weather.
- Agreed crop limits, measured energy and repeatable acceptance checks.
Source notes
- Research / technical guidance · 2005Ventilation for GreenhousesJohn W. Bartok, Jr. · UMass Extension
University engineering guidance on ventilation, fan systems and cooling limitations. Sizing examples are contextual rules of thumb.
- Research / technical guidance · n.d.Reducing Humidity in the GreenhouseUMass Extension / University of Connecticut
University explanation of humidity and condensation; used for physical principles, not a universal crop recipe.
- Research / technical guidance · 2010Greenhouse Best Management Practices Manual · Horizontal Air FlowUMass Extension
University guidance on circulation and temperature uniformity within the greenhouse.