videoman40
Well-Known Member
HPS puts out less heat per lumen of light than fluorescent/
Based on what has been said here, I will identify a couple of comments that are not entirely false but strike me as misleading. I will also give you some info I have come across about envirolites specifically and compact fluoro's in general. Hopefully this will help you all figure out what you want to pursue for supplemental lighting.
A watt will produce about the same amount of heat whether it’s from an HPS, MH, or Fluorescent. An HPS puts out a lot more light per watt, so you’d need 800 watts of fluorescent light to equal 400 watts of HPS. You’d create more heat with 800 watts of fluorescent than you would with 400 watts of HPS.
The heat is distributed over a much larger surface area decreasing its intensity. 250 watts of cfl or T5 lighting might have 20square inches of surface area(not real figure just for example sake). This whole area is around 100 degrees, the same wattage HPS has about 2 square inches of surface area and this surface is about 700. The intensity of the heat is quite different this is why a plant cannot be within an inch or two of a 250 watt HPS(it doesn't need to be though because light intensity is similar to heat intensity), but watt for watt similar amounts of heat are produced.
First let me say that I am not going to rag on Fluoro's, I like them and think they have a valuable place in the grow room. That said, the three points listed are all problematic.
To say that an HID costs more to operate then a fluoro is just false, 250 watts of fluorescent lighting uses 1kw every four hours just the same as a 250 watt HPS or MH. In fact HID lights use slightly more then the bulb wattage suggests, probably around ten percent more watts per hour, because of inneficiencies at the ballast. Nevertheless flourescent bulbs also suffer these inneficiencies. The effect is that a 250 watt HPS might pull 275 watts from the wall per hour but give 250 watts worth of light. CFL lighting will pull 250 watts per hour but give like 225 watts of light. This means they are actually probably cheaper but not intentionally and the savings come at a cost of light produced.
One final note here, is that I have found several sources that are skeptical about the claimed lumen outputs of envirolite brand lites. Measured with a lux meter they often underperform substantially. Furthermore I have seen manufacturers that will not sell internal ballasted Compact fluorescents larger then 125 watts because ballast inefficiencies increase badly beyond that point. An example is that a 250w lamp only produces the light that a 175 watt external ballasted lamp would produce. [/font]
The heat buildup issue is a hotly debated topic. If you think about it in terms of efficiency though it is more clear. CFL's and T5's output around 90 lumens per watt. Lumens are not the definitive word on light production but they are a good enough measure of bulb efficacy for now. an HPS puts out about 110 lumens per watt and MH are around 80-90 depending on manufacturer. This means that watt for watt all these lights are converting roughly the same amount of energy into light, the rest is dissipated as heat. This would seem to suggest that they all produce roughly the same amount of heat watt for watt, in fact HPS being the most efficient would produce less heat then either MH, CFL's, or T5's. This does not mean their is no difference, Fluoros have a large surface area and a low surface temp(around 100 degrees F) a HID has a very small surface area and a very high surface temp(between 700 and 1300 degrees F depending on type of bulb) The effect is that HID's produce a very intense radiation of heat several inches from the bulb before that heat is dissipated. Fluoro's produce a low intensity heat as it is more easily dissipated from the large surface area. Both will heat a space roughly equally, though it should not be forgotten that the ballast on CFL's produces plenty of heat in itself and cannot be removed from the grow space like an external ballast for HID. Both require ventilation if lots of watts are used, however Fluoros have the distinct advantage of being able to be used in very close proximity to plants.
The third comment on Lumen output is rubbish as well. It is true that lumens decrease exponentially by the square of the distance from the bulb, but this is not an effective argument for Fluoros beating HID. The same issue that applies to heat also applies to light output as well. HID's produce a small point of light that can be controlled in a directional manner very easily. Foot candle penetration far exceeds that from Fluoro's. You might think of it like this, because a fluoro has such a large surface area the total output is actually divided by that area. This means that a square inch say, of light on the bulb actually produces 700 to 1000 lumens, at no single point on the bulb does luminance exceed that 700-1000 lumens. This effectively means that in order for a plant to recieve several thousand lumens it has to be within a couple inches of several square inches of surface area, or very close to the bulb. Thus foot candle measurements one foot from the bulb work off of this 700-1000 rather then the total output of the bulb. An HID in contrast, due to its focal point of light actually produces nearly its entire output in 1 or 2 sqaure inches of surface area. Thus conservatively the foot candle measurement begins with at least half of the bulbs total output. This is why HID's have such superior penetration to fluoros. [/font]
The comments on color spectrum are a little off as well. As I have said it is true that HID lights produce a fair amount of light outside of the photosynthetically active spectrum for plants, however this applies to fluoros as well. Envirolites are advertised as producing 100% par(photosynthetically active radiation). This claim is extremely misleading, what they mean is that the bulbs produce an equal amount of photosynthetically useful energy as the sun does. The math is quite complex but suffice to say that PAR is a measure of photons, not light intensity or even energy really. Light is both a wave and a particle, different wavelengths carry different amounts of energy but all are made up of photons. Par is a measure of photons lumens are a measure of wavelength. One photon excites one electron. PAR for the sun is roughly 2000 umol per square meter per second. The envirolites produce an equivalent amount of energy as this. This claim suffers from the same problems as lumens output however, as distance from the bulb increases this number drops, what it does say is that at some unspecified range the bulb produces the same energy (not wavelengths or spectrum) as the tropical sun at noon. HID's do this just as well and as usual high par numbers penetrate much farther from the bulb because they start at much higher values just like luminous intensity. Plants can only process a certain amount of PAR this is why Co2 can be usefull and why there is no need for a 1kw HPS to be within 5-6 inches of the plant tops. HID's are used because they provide 100% par a foot or more from the bulb, 1kw lights still produce it nearly 2 ft from the bulb.
So what does this mean?
Well as I said They have ther place, the fact is that a plant in veg does not need as much light as a plant in flowering. I like to save some cash and will veg under blue envirolites, then come flower time the hps kicks in. Flouros also make great wall lighting to give some side lighting since the plants can get close. you can even hang them down into the plants if you fashion a plastic tube around the bulb to keep the plants an inch form it.
Well I was gonna put in some pics of spectrum charts but couldn't find any of good quality so sorry about the lack of visual aides. And sorry about the length but hope it helps.
Based on what has been said here, I will identify a couple of comments that are not entirely false but strike me as misleading. I will also give you some info I have come across about envirolites specifically and compact fluoro's in general. Hopefully this will help you all figure out what you want to pursue for supplemental lighting.
A watt will produce about the same amount of heat whether it’s from an HPS, MH, or Fluorescent. An HPS puts out a lot more light per watt, so you’d need 800 watts of fluorescent light to equal 400 watts of HPS. You’d create more heat with 800 watts of fluorescent than you would with 400 watts of HPS.
The heat is distributed over a much larger surface area decreasing its intensity. 250 watts of cfl or T5 lighting might have 20square inches of surface area(not real figure just for example sake). This whole area is around 100 degrees, the same wattage HPS has about 2 square inches of surface area and this surface is about 700. The intensity of the heat is quite different this is why a plant cannot be within an inch or two of a 250 watt HPS(it doesn't need to be though because light intensity is similar to heat intensity), but watt for watt similar amounts of heat are produced.
First let me say that I am not going to rag on Fluoro's, I like them and think they have a valuable place in the grow room. That said, the three points listed are all problematic.
To say that an HID costs more to operate then a fluoro is just false, 250 watts of fluorescent lighting uses 1kw every four hours just the same as a 250 watt HPS or MH. In fact HID lights use slightly more then the bulb wattage suggests, probably around ten percent more watts per hour, because of inneficiencies at the ballast. Nevertheless flourescent bulbs also suffer these inneficiencies. The effect is that a 250 watt HPS might pull 275 watts from the wall per hour but give 250 watts worth of light. CFL lighting will pull 250 watts per hour but give like 225 watts of light. This means they are actually probably cheaper but not intentionally and the savings come at a cost of light produced.
One final note here, is that I have found several sources that are skeptical about the claimed lumen outputs of envirolite brand lites. Measured with a lux meter they often underperform substantially. Furthermore I have seen manufacturers that will not sell internal ballasted Compact fluorescents larger then 125 watts because ballast inefficiencies increase badly beyond that point. An example is that a 250w lamp only produces the light that a 175 watt external ballasted lamp would produce. [/font]
The heat buildup issue is a hotly debated topic. If you think about it in terms of efficiency though it is more clear. CFL's and T5's output around 90 lumens per watt. Lumens are not the definitive word on light production but they are a good enough measure of bulb efficacy for now. an HPS puts out about 110 lumens per watt and MH are around 80-90 depending on manufacturer. This means that watt for watt all these lights are converting roughly the same amount of energy into light, the rest is dissipated as heat. This would seem to suggest that they all produce roughly the same amount of heat watt for watt, in fact HPS being the most efficient would produce less heat then either MH, CFL's, or T5's. This does not mean their is no difference, Fluoros have a large surface area and a low surface temp(around 100 degrees F) a HID has a very small surface area and a very high surface temp(between 700 and 1300 degrees F depending on type of bulb) The effect is that HID's produce a very intense radiation of heat several inches from the bulb before that heat is dissipated. Fluoro's produce a low intensity heat as it is more easily dissipated from the large surface area. Both will heat a space roughly equally, though it should not be forgotten that the ballast on CFL's produces plenty of heat in itself and cannot be removed from the grow space like an external ballast for HID. Both require ventilation if lots of watts are used, however Fluoros have the distinct advantage of being able to be used in very close proximity to plants.
The third comment on Lumen output is rubbish as well. It is true that lumens decrease exponentially by the square of the distance from the bulb, but this is not an effective argument for Fluoros beating HID. The same issue that applies to heat also applies to light output as well. HID's produce a small point of light that can be controlled in a directional manner very easily. Foot candle penetration far exceeds that from Fluoro's. You might think of it like this, because a fluoro has such a large surface area the total output is actually divided by that area. This means that a square inch say, of light on the bulb actually produces 700 to 1000 lumens, at no single point on the bulb does luminance exceed that 700-1000 lumens. This effectively means that in order for a plant to recieve several thousand lumens it has to be within a couple inches of several square inches of surface area, or very close to the bulb. Thus foot candle measurements one foot from the bulb work off of this 700-1000 rather then the total output of the bulb. An HID in contrast, due to its focal point of light actually produces nearly its entire output in 1 or 2 sqaure inches of surface area. Thus conservatively the foot candle measurement begins with at least half of the bulbs total output. This is why HID's have such superior penetration to fluoros. [/font]
The comments on color spectrum are a little off as well. As I have said it is true that HID lights produce a fair amount of light outside of the photosynthetically active spectrum for plants, however this applies to fluoros as well. Envirolites are advertised as producing 100% par(photosynthetically active radiation). This claim is extremely misleading, what they mean is that the bulbs produce an equal amount of photosynthetically useful energy as the sun does. The math is quite complex but suffice to say that PAR is a measure of photons, not light intensity or even energy really. Light is both a wave and a particle, different wavelengths carry different amounts of energy but all are made up of photons. Par is a measure of photons lumens are a measure of wavelength. One photon excites one electron. PAR for the sun is roughly 2000 umol per square meter per second. The envirolites produce an equivalent amount of energy as this. This claim suffers from the same problems as lumens output however, as distance from the bulb increases this number drops, what it does say is that at some unspecified range the bulb produces the same energy (not wavelengths or spectrum) as the tropical sun at noon. HID's do this just as well and as usual high par numbers penetrate much farther from the bulb because they start at much higher values just like luminous intensity. Plants can only process a certain amount of PAR this is why Co2 can be usefull and why there is no need for a 1kw HPS to be within 5-6 inches of the plant tops. HID's are used because they provide 100% par a foot or more from the bulb, 1kw lights still produce it nearly 2 ft from the bulb.
So what does this mean?
Well as I said They have ther place, the fact is that a plant in veg does not need as much light as a plant in flowering. I like to save some cash and will veg under blue envirolites, then come flower time the hps kicks in. Flouros also make great wall lighting to give some side lighting since the plants can get close. you can even hang them down into the plants if you fashion a plastic tube around the bulb to keep the plants an inch form it.
Well I was gonna put in some pics of spectrum charts but couldn't find any of good quality so sorry about the lack of visual aides. And sorry about the length but hope it helps.
