LEDs or HPS?

[Merkle420]

You keep pushing the goal line back but sure. We buy lights to put into small thermosealed boxes, not to grow with. Why is it people that are having heat problems swap to led to stop it?
And wattage doesn't matter. You don't buy a 600 watt led to replace a 200watt hps do you? No. You buy a 600w led to replace a 600w hps. Even though it's not actual draw. If it was actual draw you be replacing 2/3 600w hps. So we'll use logic. One 600 watt led. And 2/3 600w hps both in identical boxes, thermosealed, no third party cooling, who gets hotter.

 

[TorturedSoul]

Why is it people that are having heat problems swap to led to stop it?

Because of a general lack of understanding of the relevant concepts, lol?

And wattage doesn't matter. You don't buy a 600 watt led to replace a 200watt hps do you? No. You buy a 600w led to replace a 600w hps. Even though it's not actual draw. If it was actual draw you be replacing 2/3 600w hps.

Hey, ICEMUD!!! (lol)

So we'll use logic.

Yes, please do. That would make the discussion both much less painful and much more beneficial.

One 600 watt led. And 2/3 600w hps both in identical boxes, thermosealed, no third party cooling, who gets hotter.

<SCRATCHES HEAD> That's a little difficult to decipher with 100% certainty this time of night, lol. So how about this:
Two electrical devices that are consuming the same amount of wattage tend to produce comparable amounts of heat.

 

[Merkle420]

No they actually don't. Would a 2000w heater make as much heat as a same watt freezer? You don't seem to understand the fact that different types of lighting have different efficiencies. We use 150 ACTUAL draw led floodlights, they never get hotter than a 60 watt incandescent.

 

[Merkle420]

Or perhaps explain heat bulbs for cold blooded animals. Same wattage as uv bulbs but higher temp.

 

[Icemud]

I'm sorry but I very much disagree, I've got my vipar 600 on full all day and I can hold my hand against the glass and it's hardly warm.

You feel very little heat because what you feel are light photons being absorbed into your skin. LED's put out very little if any radiant heat but they unlike other light types like HPS, incandescent ect.. instead all the heat is output throught that back of the led which is why heat sinks and typically fans are needed and used. Because you dont feel heat doesn't mean they aren't putting out a lot of heat... it means its being spread through convection and conduction by the heatsinks.

The efficiency doesn't matter in a closed space as like you feel on your hand getting warm under the LED. photons degrade into heat (the lowest form of energy) when they hit a surface and absorb. The reason that efficiency doesn't matter is think of this...

Lets say you have a 50% efficient bulb. That bulb puts out 50% light, and 50% waste energy as heat. But in an enclosed space, the light would turn into heat, and the waste energy is already heat, therefore still 100% of the energy as heat would end up in the room, unless it was removed somehow. Either way, the heat load is a direct relation to wattage draw.

What you are thinking is in reference to home lighting, where LED's are used to reduce heat... its not because they are cooler though. It's because they are more efficient, therefor to get the same lumen output takes less wattage..(for instance you can replace a 60w incandescent with a 26w cfl, or a 10w LED) well the LED will be 6x cooler than the incandescent, and about 2.5x as cool as the CFL.
They all put out the same light, which in a housing situation with human eyes then the reason the cooling is not because leds are cooler, its because they require less watts to produce the same light. I hope this make sense.

Energy is never created or destroyed... so regardless of efficiency, the energy just changes form in different ways and eventually reaching the lowest form which is heat. So in a sealed grow room, if all fans are off and no air escapes... 600w of energy, whether its 50%light/50% heat, or 40%light/60%heat... both put 100% of the energy into that room, and when the light turns into heat from hitting the walls and floors this is added to the room as heat energy. We are talking in terms of physics though so no heat would be allowed to escape.

In reality though, we don't have perfection as physics would prefer, so there are other factors at play which will influence how the light interacts with the surfaces, air molecules, water vapor, etc... and these factors could influence the results of being exactly equal slightly in a real world environment.. mostly based on differences of spectrum and how this light would absorb and how the heat would transmit out of the area.. so this would effect the perfection of the physics involved with this, however generally speaking, same wattage, same heatload in a close environment.



Now in cases where you have a LED fixture vs a HPS light with a air cooled hood... at equal wattage the room with the air cooled HPS will be cooler than the same wattage LED because the HPS is immediately evacuating a good portion of the heat out of the grow area without letting it enter. The LED however dumps hot air right into the grow area, and with most LED's haveing no way to duct it out or directly pipe the warm air out... the LED environment will heat up faster and maintain hotter temps...

 

[Merkle420]

Or another way of thinking.
600 hps puts out 40% heat or there abouts. How does a MORE efficient led put out 90% of its heat while staying more efficient?

 

[Icemud]

Or another way of thinking.
600 hps puts out 40% heat or there abouts. How does a MORE efficient led put out 90% of its heat while staying more efficient?

because both light, and waste heat, become heat... no energy is created or destroyed, just changes form. (heat is the lowest form of energy). Therefore 40% heat is heat, 60% light becomes heat, therefore 100% of the energy introduced into the closed grow area becomes heat. (other than the stored photons which is very minimal).

Led's are not 90% efficient though. I think the best ones right now are around 60%.

This is how BTU's translate to heat load, 1W = 3.41 BTU approx therefore regardless of efficiency, 1W = 3.41 BTU.

 

[TorturedSoul]

Lets say you have a 50% efficient bulb. That bulb puts out 50% light, and 50% waste energy as heat. But in an enclosed space, the light would turn into heat, and the waste energy is already heat, therefore still 100% of the energy as heat would end up in the room, unless it was removed somehow. Either way, the heat load is a direct relation to wattage draw.

THANK YOU! I knew this stuff in my mind (sort of, lol - and it helped that I've seen a thread "or two" of yours before). But correctly explaining the concepts in straight English at 4:00am after my third night of two hours' sleep per, lol...

BtW, do you... run a little place called the Hayden Planetarium in your spare time? That's it, ha ha, I cracked your identity and you're actually Neil deGrasse Tyson!!! Yeah, that's it. Because you and Neil... No matter what I ask, I get an answer, and the answer uses logic AND common sense, and manages to spear right into the ol' gray matter like a cluster headache (only without all the pain, nausea, and pitiful noises ).

Anyway... Thank you, bro. And sorry to be a bother.

Hey, Merkle420, if it helps at all, I had some trouble with some of this stuff initially, too. Some of it seems almost counterintuitive at times. And I wasn't truly understanding what I was observing. It's like the one where 600 watts' worth of CFLs might not seem to be producing as significant an amount of heat as one 600-watt HPS - because if you stick your ear against the HPS bulb, there will be odd smells of cooking pork and, perhaps, a scream or two, lofl, but one can hold a CFL in one's hand. However... 10,000 birthday candles can produce enough heat to cook dinner, just like an oven. It's just concentrated into (more or less) a single point, IOW, it is more diffuse(?) and, therefore, seems less.

This is how BTU's translate to heat load, 1W = 3.41 BTU approx therefore regardless of efficiency, 1W = 3.41 BTU.

That's it! People with large-scale commercial grow rooms (and little guys dealing with Summer temperatures) need to size their air conditioning for their setups, and in order to do that, they have to track every... last... bit... of it. Ergo, wattage/heat calculations like the above are pretty standard in the industry.

 

[Maximo]

"therefore 100% of the energy introduced into the closed grow area becomes heat."

Not quite, though I agree with everything else said. For equivalent wattages, HPS and LED produce around the same amount of heat.

The more plants you have, the more light energy will be converted to chemical energy by the process of photosynthesis.
That figure is probably less than 20%. Plants help cool an environment.

 

[Slicknick909]

I've tried them all, MH, CMH HPS, LED and plasma/t5ho. LED is a complete waste of money unless you build a proper COB rig, I was planning on it until I got a hold of 3 315w CMH for a steal. I'm using about 1/4 as much cal mag and thanks to the near sunlight coloration I can spot a deficiency exponentially faster.

 

[Merkle420]

Yeah but the fact still stands if you want a grow that needs a 600watt hps you don't need 600 actual watts to do that with led. Therefor you won't have heat problems like you would with a hps unless you're getting a 1200 watt led, even then the efficiency on a 1200 watt hps is still better than a 600 watt hps.

 

[Merkle420]

I've tried them all, MH, CMH HPS, LED and plasma/t5ho. LED is a complete waste of money unless you build a proper COB rig, I was planning on it until I got a hold of 3 315w CMH for a steal. I'm using about 1/4 as much cal mag and thanks to the near sunlight coloration I can spot a deficiency exponentially faster.

Complete waste of money....
Why? I'm doing fine with my grows and the fact that I'm using way less electricity factors in aswell. The cost of an led panel was less than the cost of an equivalent hid not to mention the added cooling needed.

 

[Bloodguy]

I like my hids. I like my LEDs. I'm keeping both. They all have their places in my grows. I even have a couple seeds in Solo cups under CFLs. The goal is to grow our own. With thousand dollar cob arrays or unbranded Chinese leds or hids or bday candle light.

 

[Icemud]

"therefore 100% of the energy introduced into the closed grow area becomes heat."

Not quite, though I agree with everything else said. For equivalent wattages, HPS and LED produce around the same amount of heat.

The more plants you have, the more light energy will be converted to chemical energy by the process of photosynthesis.
That figure is probably less than 20%. Plants help cool an environment.

That is correct, I thought I mentioned this but maybe I left it out.. Yep... the energy that is absorbed into the plant does have an effect, I think the number is quite low though if I can recall. Somewhere around like 5% or so of the total light is actually used and stored. Even some of the light, when used by the plant turns back into heat too. Its minimal but you are correct. (my 5% may be incorrect but I think that is what I remember reading)

 

[Slicknick909]

Yeah but the fact still stands if you want a grow that needs a 600watt hps you don't need 600 actual watts to do that with led. Therefor you won't have heat problems like you would with a hps unless you're getting a 1200 watt led, even then the efficiency on a 1200 watt hps is still better than a 600 watt hps.

1. There's no such thing as a 1200w hps
2. A 600w hps is the most efficient single ended hid bulb as far as output vs input.
3. Actual watts vs actual watts is the only way to accurately compare efficiency.
4. The PAR value for LED compared to CMH is shit, lumens are for humans.
5. 1200w of heat is 1200w of heat regardless of LED, CFL or HID.
6. You may get alright results with LED, but is the plant growing to its full potential in blurple vs if you used full spectrum? Doubtful...

Other than to save a few bucks in veg I don't see any viability for the cheap chinese led panels, especially the poorly built failure prone mars.

 

[Icemud]

Yeah but the fact still stands if you want a grow that needs a 600watt hps you don't need 600 actual watts to do that with led. Therefor you won't have heat problems like you would with a hps unless you're getting a 1200 watt led, even then the efficiency on a 1200 watt hps is still better than a 600 watt hps.

That is correct, and also the "half truth" that LED companies like to say about their products because "cooler than HPS" sounds great. Its semi true because as we just talked about, lower wattage equals lower temps and most LED grows can get by with about 20% less energy to get the same PAR light. I've seen some as good as 40% but its unlikely and generally the LED's have to compliment the grow style by design to get these types of savings.

Buuutttt... Like I mentioned in the longer post... HPS can actually be cooler, because of Air cooled hoods. They significantly reduce the heat that is released into the grow area (but also cut down on light slightly too) but a HPS with a air cooled hood can also be cooler than an LED because 100% of the heat from LED enters the grow area.. with HPS I don't know the percentage, but I would guess at least 30% or more is directly evacuated by the ducting fan and out.

But yes... this is correct that its semi true that LED can be cooler, not always based on their ability to put out as many photons with less energy.

 

[lootznbootz]

Ss

 

[TorturedSoul]

Its semi true because as we just talked about, lower wattage equals lower temps and most LED grows can get by with about 20% less energy to get the same PAR light. I've seen some as good as 40% but its unlikely and generally the LED's have to compliment the grow style by design to get these types of savings.

I've wondered about the penetrative ability of a panel comprised of multiple low-wattage LEDs (versus the typical 400-, 600- and 1,000-watt HPS used in flowering). COBs (driven at sufficient wattage) seem to have decent ability in this regard, although I cannot quantify that against the HIDs.

HPS can actually be cooler, because of Air cooled hoods. They significantly reduce the heat that is released into the grow area

Where heat is concerned, THAT is most folks primary concern (assuming the LED panel can at least properly ventilate itself and, therefore, not suffer degradation and poor service life, lol).

(but also cut down on light slightly too)

A relatively small but still significant amount, it must be said. Seems like I once read it was typically between 4% and 9% depending on the quality of the glass used, but it has been years and I might be misremembering the exact numbers.

The fact that glass attenuates the light slightly is one of the reasons I've not been a fan of Cool Tube setups. The light that goes upward has to pass through a layer of glass multiple times in the act of being reflected back downwards towards the plants, further reducing its intensity.

but a HPS with a air cooled hood can also be cooler than an LED because 100% of the heat from LED enters the grow area.. with HPS I don't know the percentage, but I would guess at least 30% or more is directly evacuated by the ducting fan and out.

I'd guess it's the "or more" part, lol. Some folks have been able to turn down their tent's fan, set it on a timer, or in some lucky cases even shut it off altogether (great for adding carbon dioxide to the environment) when they had a good quality air-cooled HID reflector, insulated ductwork (every little bit helps)... and that whole path on a separate run, bringing air in from outside of the grow, passing it through the reflector, and moving it directly back out of the grow without ever having come into direct contact with the grow space's air. In most situations, this vast improvement in the grow room environment is well worth the bit of light energy that gets lost due to attenuation. BtW, in the spirit of "every bit helps," there have been insulated covers for most air-cooled HID reflectors for years. These help even more (albeit, not a great amount all by itself). I have yet to see such a product available for LED grow light panels (even for the one or two models that actually have a traditional IN and OUT air path (flange) out of all the ones on the market that don't).

 

[Merkle420]

I've wondered about the penetrative ability of a panel comprised of multiple low-wattage LEDs (versus the typical 400-, 600- and 1,000-watt HPS used in flowering). COBs (driven at sufficient wattage) seem to have decent ability in this regard, although I cannot quantify that against the HIDs.



Where heat is concerned, THAT is most folks primary concern (assuming the LED panel can at least properly ventilate itself and, therefore, not suffer degradation and poor service life, lol).



A relatively small but still significant amount, it must be said. Seems like I once read it was typically between 4% and 9% depending on the quality of the glass used, but it has been years and I might be misremembering the exact numbers.

The fact that glass attenuates the light slightly is one of the reasons I've not been a fan of Cool Tube setups. The light that goes upward has to pass through a layer of glass multiple times in the act of being reflected back downwards towards the plants, further reducing its intensity.



I'd guess it's the "or more" part, lol. Some folks have been able to turn down their tent's fan, set it on a timer, or in some lucky cases even shut it off altogether (great for adding carbon dioxide to the environment) when they had a good quality air-cooled HID reflector, insulated ductwork (every little bit helps)... and that whole path on a separate run, bringing air in from outside of the grow, passing it through the reflector, and moving it directly back out of the grow without ever having come into direct contact with the grow space's air. In most situations, this vast improvement in the grow room environment is well worth the bit of light energy that gets lost due to attenuation. BtW, in the spirit of "every bit helps," there have been insulated covers for most air-cooled HID reflectors for years. These help even more (albeit, not a great amount all by itself). I have yet to see such a product available for LED grow light panels (even for the one or two models that actually have a traditional IN and OUT air path (flange) out of all the ones on the market that don't).

And while people are spending money on insulting, fan forced lights and ducting, it takes an led panel, an a fan/filter and it's done. Hence the fact remains led produce less heat and using less electricity at the same time, they might be as good performance wise but atleast the diodes don't need changing every second cycle not to mention flowering/veg bulbs.

 

[Merkle420]

1. There's no such thing as a 1200w hps
2. A 600w hps is the most efficient single ended hid bulb as far as output vs input.
3. Actual watts vs actual watts is the only way to accurately compare efficiency.
4. The PAR value for LED compared to CMH is shit, lumens are for humans.
5. 1200w of heat is 1200w of heat regardless of LED, CFL or HID.
6. You may get alright results with LED, but is the plant growing to its full potential in blurple vs if you used full spectrum? Doubtful...

Other than to save a few bucks in veg I don't see any viability for the cheap chinese led panels, especially the poorly built failure prone mars.

1200 watts of heat regardless but appliances run differently. Like I said, a freezer using 800 watts compared to a clothes iron using 800watts is different, try find a place on the freezer that will give you 3rd degree burns-.-. If led's aren't more efficient why are they phasing out incandescent bulbs? They produce the same amount of light for less watts, I'm sorry but I think you just need to accept that. Now whether there better for plants I'm not sure. BUT they're better in regards to heat, running costs and for me, upfront price.