CO₂ Enrichment Calculator

Every full air turnover vents essentially all of the CO₂ that's just been added, so it has to be re-injected to hold the target level -- and because Air Exchanges/Hour can range all the way from a nearly sealed structure to ten full turnovers an hour, that swing moves Injection Rate more across its full range than the greenhouse's Length, Width, or Height do, and more than the PPM gap between Ambient and Target CO₂ does.

Injection Rate (lbs/hr) is the hourly flow needed to maintain the target level while the system runs -- it depends only on the ppm gap, greenhouse volume, and air exchange rate. Enrichment Hours/Day and CO₂ Cost only come into the picture afterward, when converting that hourly rate into Daily CO₂ Usage and Monthly Cost, so they scale the cost but not the rate itself.

Whenever Target CO₂ is actually above Ambient CO₂ (the normal case, since enrichment only makes sense when you're raising the level), every full air turnover vents essentially all the enriched CO₂ that's been added and requires re-injecting it to hold the target level, so Air Exchanges/Hour has a direct, proportional effect on both Injection Rate and Monthly Cost -- across its full 0-10 range, it's the single biggest driver of Injection Rate in that case. If Target CO₂ is set at or below Ambient CO₂, no enrichment is needed at all, so Air Exchanges/Hour stops mattering to Injection Rate entirely in that edge case. A greenhouse with more infiltration or active ventilation costs more to enrich at the same above-ambient Target CO₂ than a tighter structure.

Only approximately -- the calculator assumes a fixed plant uptake rate of about 0.02 lb of CO₂ per hour for every 1,000 sq ft of canopy at high light, which is a general planning figure, not a measurement of your specific crop. Actual uptake varies with plant density, growth stage, and light intensity, so treat the plant-uptake portion of Injection Rate as an approximation layered on top of the more precise air-exchange math.

It doesn't model CO₂ stratification within the greenhouse, leak rates beyond the stated Air Exchanges/Hour figure, or the occupational-safety monitoring needed if workers are present while CO₂ is elevated -- concentrations much above the levels modeled here can become a health concern for people working in the space, so any enrichment system should include monitoring and follow local safety guidance, not just this cost estimate.