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Why do Incandescent lights suck? By St0ney

We get asked this question about 1000 times a week so, I did a bit or research for you all. Here is the problem with incandescent lights (and halogens, which are just high pressured incandescents)... When electricity is used for lighting some of that electricity is used for creating the light and the rest is turned to heat. In the incandescent bulbs, much more heat is produced then useable light, usually around 80-90% of the electricity used to power the incandescent is turned to heat not light. As an example: Forty 100-watt incandescent lamps (4,000w = 68,000 lumens) require 12,283 Btu of cooling (slightly over one ton). The same site could use 27 four-lamp fluorescent fixtures (or about 4,000 watts = 240,000 lumens) at the same one ton of cooling load, yet produce 172,000 more lumens. (Please see: http://tristate.apogee.net/cool/cfrl.asp for more information on this.)   Let’s do some math Fluorescents produce more light per watt used then any incandescent can ever do. HID (HPS in particular) produce WAY more light for every watt used. 150w of Light Total Lumens Lumens per Watt 150w incandescent 2,550 lumens 17 lumens per watt 150w halogen 3000 lumens 20 lumens per watt 150w of Fluorescents 9,000 lumens 60 lumens per watt 150w of Compact Fluorescents 10,500 lumens 70 lumens per watt 150w Metal Halide 13,500 lumens 90 lumens per watt 150w High Pressure Sodium 16,000 lumens 107 lumens per watt   Now since you're paying for each watt used wouldn’t you want that watt to put out as much light (lumens) as it could? Using an incandescent bulb you are going to pay way more in electric costs then you would if you used a HID because you’ll need more watts for the grow to come out good. To produce killer bud you will need about 7,000 lumens per sq ft in your grow room. So, in a 5sq ft grow room you would need 35,000 total lumens (7,000 * 5 = 35,000) to reach the optimum 7,000 lumens per sq ft. To get 35,000 lumens you would need: # Of lights needed Type of light Total watts Equals 13.7 150w incandescent 2,058 watts 35,000 lumens 11.6 150w Halogens 1750 watts 35,000 lumens 3.8 150w Fluorescents 583 watts 35,000 lumens 3.3 150w Compact Fluorescents 500watts 35,000 lumens 2.5 150w Metal Halide 389 watts 35,000 lumens 2.1 150w HPS 327w 35,000 lumens   Now according to our Grow Guide (lighting section): To determine the cost of operating your light: Find your KWH charge on your electric bill. Assume you have a 1000 watt light and your KWH charge is $.05/hour. A kilowatt equals 1000 watts, therefore it will cost you .05 cents per hour to run that light. Here's another example. Say you have a 400 watt light and your KWH charge is $.03. Since 400 watts is not a kilowatt, you must divide 400 by 1000 = .4 kilowatts x .03 (KWH rate from electric bill) = $0.012 cents per hour to run.   So, let's use me as an example, I pay $0.08 per KWH. Using our 5 sq ft grow room example above and shooting for 7,000 lumens per sq foot: Incandescent lights 2,058w = $0.16 an Hr (2.058*0.08=0.16464) or $3.84 a day (0.16*24=3.84) or 115.20 a month (3.84*30=115.20) or 1,382.40 a year (115.20*12=1382.40) Halogen lights 1750w = $0.14 an Hr or $3.36 a day or $100.80 a month or $1,209.60 a year. Fluorescent lights 583w = $0.05 an Hr or $1.20 a day or $36 a month or $432.00 a year. Compact Fluorescent lights 500w = $0.04 an Hr or $.96 a day or $28.80 a month or $345.60 a year. Metal Halide 389w = $0.03 an Hr or $.72 a day or $21.60 a month or $259.20 a year. High Pressure Sodium 327w = $0.03 an Hr or $.72 a day or $21.60 a month or $259.20 a year. As you can see it adds up real quick. In one month of 24hr light I would spend $93.60 more to run incandescent lighting than I would for a HPS and in a year it would cost me $1,382.40 to run those same incandescent lights 24 hrs a day when it would only cost me $259.20 to run the HPS. That’s $1,123.20 more it would cost me per year to run an inferior light. Not to mention how much more it would cost to cool that same 5sq ft grow space running incandescent light over HPS. So, as you can plainly see even if the light spectrum was correct and heat wasn’t a problem it would cost you WAY more to run incandescent/halogen lights than it would to run a HID. The money you save in just one month would almost pay for the HPS. When you break it down to cost per watt doesn’t it make more sense to buy the HID in the first place? Incandescent lights..... More costly then we all thought.

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