A controlled unit has insulated rooms, an air handling unit that cools and humidifies, and usually a Phase II tunnel. ICAR-DMR's planning model assumes 60 day crops, 6 crops per room per year and an air to bed ratio of 1 to 5.
The price of independence from weather is a machine that must run every hour. A controlled farm is judged on crops completed per room per year and on how evenly its rooms perform. One good crop proves nothing, six in a row prove the system, and the power bill has to be paid by the crop.