no bob....open batwing hoods...and 3500btu of cooling per 1000w is good if using co2, if not using co2 2800btu of cooling per 1000w is sufficient.....here is a quote from bchardcore
full story here
part1- http://www.cannabisculture.com/articles/3268.html
part2- http://www.cannabisculture.com/articles/3368.html
Air conditioning
Obviously, large commercial grow rooms depend on industrial-strength air conditioning (A/C) units.
Hardcore says it's relatively easy to calculate A/C needs. Air conditioners are rated by a "BTU" cooling capacity per ton; they are rated at 12,000 BTUs for every ton of cooling capacity. Each 1,000-watt HPS light in a CO2-augmented room requires about 3,500 BTUs of cooling to maintain a target ideal growing temperature of 78?F (25?C). For every 1,000-watt light in a non-CO2 grow room, growers need about 2,800 BTUs of cooling capacity.
These formulas can be downsized by 10% if light ballasts and CO2 generators are located in a central room outside the grow room.
In some commercial houses, growers use five-ton water-cooled air conditioners; a five-ton A/C unit provides 60,000 BTUs of cooling.
Other growers use "split" air conditioners that have a compressor outdoors and the cooling A-frame indoors. An A-frame split air conditioner uses air to cool the Freon and compressor, while water-cooled air conditioners use water for this task.
Water-cooled units are less noisy: they don't have a fan and compressor running outside the grow house, as often occurs with a split five-ton. Water-cooled air conditioners use five gallons of water per minute, so people who rely on wells or other insufficient water supplies can easily run out of water.
Water companies monitor usage on behalf of drug warriors, and even if drug warriors aren't monitoring water usage, the water bill can be very large. That's why commercial growers often use above-ground swimming pools to store and recirculate water for water-cooled units. Some growers also lower their water bills by drilling holes in the water-measuring paddles of water meters.
The water-cooled A/C preferred by Hardcore is an "active" system that uses a compressor and Freon. So-called "passive" systems cool by running water through a coil that air is blown over, and they are less expensive to use.
For every three 1,000-watt lights, growers should use one 16-inch oscillating fan. Along with the obvious benefits of increased air circulation, fans blowing on plants will force thicker stalk development, which will create better nutrient circulation, healthier plants, and increased yield.
In some circumstances, it might be necessary to pull moisture out of the air to maintain ideal humidity between 40-50%. Dehumidifiers with drain systems offer one solution, but Hardcore prefers to outfit his air conditioner units so they also function as dehumidifiers.
He installs a heater core in an A-frame cooler inside the grow room. As the A-frame air conditioner runs it dehumidifies the room and is also cooling the room at the same time. The heating core is necessary because the cooling unit will keep on cooling as it dehumidifies, which can drop room temperature below 78?F (25?C). The heating core boosts temperature back up to 78?F (25?C) and also helps dehumidify rooms more efficiently because warmer air holds more moisture.
So.....As cost is kinda becoming an issue I was wondering what you guys thought about these 24,000 btu window units.
