yea i recently bought a 150 hps light and was wondering should it look supper bright ? or more bright than 120 watss of cfls ... at close it deosnt look so much brighter but the cfls lights the room alot further than the hps......can the bulbs lumen output be affected over long use or ??
cfls are far less efficient than hps, it should put out around 15,000 lumens so yea it should be pretty bright
150watts hps is definately more lumens. A good bulb will have about 16,000 lumens. CFL's have a lower watt to lumen ratio and an equal amount of watts would be less lumens. You could possibly get 7,000 to 10,000 lumens with 120watts of cfl ,depending on what kind of bulbs are used.
I think the hps is higher too. Even though the cfl is really bright its also showing a full spectrum light, when blue is mixed in the light will look brighter. Where hps win over cfl though is the higher lumen output. The further you get away from the light source the lumens get cut in half. With HPS you're starting out at a higher number so you still have optimal lumen all over the plant
A 150w HPS bulb is brighter. As for which lights the room wider, I imagine the HPS has a reflector hood so the light is being channeled, you can't compare. And yes, HPS bulbs do lose output strength when they get older.
Not half, but exponentially. An important equation to remember is I=L/D^2. Intensity (I) = Lumens (L) divided by the Distance (D) squared (^2). From the source I read it from, they were using a 1000lumen example bulb. At 1 feet away, the intensity of the light is 1000 lumens. At 2 feet, the intensity is 250 lumens. At 3 feet, 111 lumens and at 4 feet, only 52.5 lumens. A 150w HPS might produce more lumens over a 120w CFL, but you could place a 120w CFL marginally closer than the 150w HPS
Debending on the brands of bulbs, a 100w HPS is also brighter than a 120 watt cfl 100w hps around 10k lumens 150w hps around 15k lumens 50w CFl around 3.5k lumens 120w CFl around 9k lumens 250w CFl around 16k lumens You should be aiming for about 10k lumens per plant by the way, not the old "Rule of thumb" which many people here seem to use; "100 watts of light per plant" (and variations inculding "50 watts of lights for each plant after the first) This statement is based on old HPS bulbs, and doesnt take into account that 100w's of CFl lighting would provide far less usuable light for your grow.
Place the HPS in a cooltube, and it can be hung at the exact same distance as the CFl, while providing far more usuable light energy