A 400 watt lightbulb actually consumes closer to 440 watts of total power including PSU losses, so it consumes: (440 watts) x (1KW/1000W) x ($0.10/kWh) x (12 hours) = < b>$0.528 per day or $192.72 per year.
At an average cost of 0.09 cents per kilowatt, a system of 1,000 400-watt metal halide lights costs $41.22 per hour. If the lights run an average of 730 hours each month (730 x $41.22), that ends up costing $30,090.60 each month, or $30.09 per month in energy per light.
It is important to note that a 400W heater consumes 0.4 units when running for 1 hour, while a 2000W heater consumes 2 units when running for 1 hour runs for 1 hour. So more heat, more watts and therefore more units consumed.
In general, grow lights using 200-400W can grow about 1-3 plants per light; Lamps using 500-700W can grow about 4-5 plants per lamp; and lamps consuming over 800W power can grow 6-8 plants per lamp.
400 watt HPS grow lights are the most commonly used HPS grow lights, covering about 16 square feet and capable of high yields
As an aside, a 400-watt HPS light initially delivers about 50,000 lumens. As a rule of thumb, reduce the HPS lumen output by half to find the LED lumen output, which in this case would be 25,000 lumens.
The 400 watt heater is ideal for a standard sized room up to (120 m² ft.). These units are not only perfect for providing extra heat, but also for warming up cold spots in the house.
Ironically, most HID grow light enthusiasts recommend using both MH and HPS grow lights. MH (Metal Halide) grow lights are best for vegetative growth and HPS grow lights are better for flowering.
Most growers prefer something between these two extremes with about nine plants in a 4X4 grow room. This will give you about a square foot per plant. Autoflowering plants are always the same size as they don’t have a vegetative period.
Best indoor marijuana yield
In theory, the math is easy. 400 watts from an HPS grow light could result in 400 grams (14 ounces) of weed at the end of the day. 1200 watts would result in 1.2 kilos (42 ounces) of marijuana etc.
LED grow lights are preferred because they use less power than HPS lights. According to market research, LED lights use 90 percent less electricity than HPS grow lights. You will have less electricity and circuit breakers at home as LED grow lights improve the energy efficiency of your indoor garden.
HPS lights should not be placed inches away from the plants like you would place fluorescent lights; You should place HPS lights higher up, generally between 5 and 8 feet away from the plants. Whether or not you have a reflector with your HPS light makes a difference in how close you can get it to the plants.