I built this greenhouse, which is 1730 sq ft, in 2003 with all the equipment (sprinkler system, heater, automated thermostat controller, HAF fans, exhaust fans) for under $20,000. I did it because I was running a 'niche' tropical plant nursery mail order, AND to house my tropical plant collection which at that time was already huge. When I built it, my climate zone was 8B. We have moved to 9A, and just had our first 10A winter.
