Heat problems with LED grow lighting - All brands discussion

Icemud said:
Hey everyone....

I wanted to see how many others out there were having heat issues with their LED grow lights.

The issue: My issue with ALL current LED grow lights is they all advertise "lower heat". I find this not entirely true and even though there is some truth to the lights running at cooler operating temperatures, *bulb temp, but I don't find any of my LED grow lights reducing the heat of my grow area over HID...

Now where this problem lies...All LED lights currently on the market have fans that either suck air in, or blow air out... Now the problem with the current design of LED grow lights is that you have something evacuating "warm/hot" air from the light, into your garden/grow area, without any way to evacuate the heat like HID lights do with air cooled hoods and such...this is whats causing a heating up of a tent. Its like putting a heating pad in a box...eventually, even though the heating pad is cool to the touch for a human (wont burn) it still will over time heat up that box, because the heat is building up in the box, without means of excape. Same as the LED lights... May not be hot to touch, but still let heat fill your grow area...

So even though the lights may run cooler overall, they do not offer a solution to extract the hot air from the light and push it outside of your tent....


I wanted to know if anyone else is having issues with LED grow lights heating up your grow environment more or equal to HID lights...


I know that both of my brands of LED I have used do this, and actually run hotter than my 1000w setup I had, only running 600w of LED.... My Top LED tent used to run about 82F with my HID's on full blast, currently it is running around 84-85F with the Mars II, not a decrease in Temps at all...

Who else noticed this, what model do you have, did you find a solution????
Click to expand...

The reason is down to how energy efficient they are, and in truth they have only just started to overtake HIDs when it comes to energy efficiency HIDS will convert about 25% electric into visible light the majority of current LEDs will convert about 35ish% into visible light the in both cases 75% and 65% waste is heat that is why there will not be much temperature difference between the 2.

Watt for watt a 1000w actual draw led and a 1000w HID will both have the same heat issues as the conversion factor is similar, so its a myth that they are more energy efficient and run at lower temps, but the technology is steadily improving, so it will get there one day just not yet.
 
john, While the basis of your statement is correct, your numbers are off significantly. HPS is ~32% efficient depending on a few factors and the newest generation of LEDs are 48%+ with rumors of over 50% efficiency in the newest Bridgelux and Cree diodes getting ready to hit the market. LEDs surpassed HPS in lumens per watt over (and efficiency by virtue of physics) over 2 years ago.
 
Hi hosebomber the figures I quoted were rough averages for each of the markets based upon the tech the majority of people and companies will have in their hands today and tomorrow if that makes sense. Their are actually much higher efficiencies to be had with Leds I have seen a lab figure of 70%, the thing is HID and fluoro tech could be doubled in efficiency yesterday it's gamesmanship by the industry.

Also an Leds quoted lab performance figures under optimal conditions and actual real world performance can vary significantly, shortened lifespan due to heat for one, and wavelength shifts due again to heat, so I would be cautious taking such figures at face value and thinking it is an overall representation of that Leds performance because there is more to it than that.

Personally I do not like the lumen per watt figure it's deceptive, they used to go by millicandela and should have moved onto candela or quote lux figures, it paints the picture more accurately, As an example you have a 20, 40 and 60 degree angled 1 watt LED’s all 3 produce 100 lumens at a distance of 1 meter away, but if we did a calculation of their Lux figures this is what we would find: 20deg=1048 lux, 40deg=263.9 lux and 60deg=118.8 Lux.
 
Icemud said:
Yep, My HID lights had air cooled hoods...Hosebomber hit the nail on the head
Click to expand...
This is interesting because i just logged on to read about this issue. If you were evacuating your aircooled hoods, it seems that the heat is roughly the same with the toplight LED. But if have open air cooled HID, the LED's are significantly cooler. I was gonna ask if anyone else noticed this but nevermind.
 
I know that my Top LED light is much cooler than my CFLs. I had 250 watts of CFL canopy lighting, in two separate lights, compared to the 96x3-watt reflector series LED light I now use for canopy lighting. With that being the only lighting change, I've gone from not being able to lower the grow box temps below 20° above ambient temps, to easily lowering the temps to 10° above ambient temps and possibly much lower. I will learn even more about the differences between these two during flowering when the wattage goes up and the temp range drops.
 
In order to make your comparison there is a very important key concept you are leaving out. A good quality LED puts out twice as much useable light compared to HPS with the same power input. It took me awhile to wrap my head around this fact and what it means. If you review specs on a quality LED like for example SuperGrow or CLW you will notice that it is continuously stated that it takes only a 500W LED to replace a 1000W HPS. This is because the LED puts out twice as much useable light as the HPS. With 500W input power and twice as much being converted to light by default you have less input power wasted being converted to heat. I have used both types of lights. With the air cooled 1000W HPS you can still burn your hand or plant in a heartbeat if you put them too close to the glass. With the LED there is almost no noticeable radiated heat onto the plant canopy. For SOG setups this puts a lot of light where it is needed with less heat being generated. To address your original concern about heat, it sounds like we have the need for a new product, air cooled LED.
 
People do not realise how heat sensitive LEDs are, heat does all sorts of things to an LED shortened lifespan being one wavelengths shifts being another, going by the figures above HID is 32% efficient, commercially available LED is 50% efficient this means LEDs have an 18% advantage if you like, that does not convert to them being twice as efficient as a HID, it would be more like a 1000w HID vs 640w led fixture, what else has not been thought about is coverage and penetration when factored in is an led setup actually more efficent?

Just realised I missed your point you stated usable light, but I would still dispute that point by saying everything in the 400-700nm is usable, show me a 500w led on a timelapse video that outperforms a 1000w HID, there is more going on than just spectrums trust me.

If anyone has footage of a 1000w HID vs say 1000w's worth of LEDs timelapse I would love to see the results, personally though I would be very surprised to see much difference in terms of yields, and if anyone does have timelapse footage of low watt leds outproducing big watt HIDs please post here:thumb:
 
Again think useable light. Not just light you can see with your eyes but actual red and blue light that a plant uses. LED has twice as much useable light than a HID for the same power input. And yes, LED has a weakness on penetration. HID penetrates further for what ever reason. To get the most out of your LED, grow and train your garden so the budding sites are as close to the same height as possible. You want short wide plants as in SCROG, tall skinny plants are a bad thing for LED. I have very detailed spread sheets that factor in everything i can think of in initial costs, monthly costs, yearly costs, etc.. For my setup it takes 3 years for the LED to pay for them selves. After that the savings amount to several thousand a year. For my application converting to LED saved me huge headaches in being able to do away with all the venting needed with the HID setup. No more flex hoses, inline fans etc and giant hoods to hit my head on. As you can see I am pro LED and look forward to the future as the LED technology will only get better.
 
Believe me I know a fair old bit about LEDs having built full spectrum panels way before they became fashionable there are trade off's but there position has definitely improved. The way I see it the industry is so stuck on red and blue because it supposedly is involved in 95% of photsynthesis or whatever the figures are but their is a lot more going on than 450 blue and 630 or 660 red.......I am not saying Leds don't have a place here now they do, but I see there usefulness in other ways and I still stand by the energy efficiency line as being massively inflated, I would say wait in 3 years time to see how that panel performs you may well be surprised.

Having taken a couple years out from the scene and seeing what's going on in the market it kind of makes me want to get stuck in and do my own thing...........In fact I think I will lol and when I have finished my build if the competition wants to pit their lights against mine by way of a neutral person here in this forum then I am definitely game.

In the meantime I am going to start putting pen to paper:peace:
 
My hid to led switch,
I have down sized exhaust fan
dehu runs at the last 2-3 hours of light on, pulling 13 oz of water out in stead of running constantly pulling almost 2 gallons with 2 400w hps,
ATM I have just short of 1000w of topled ( 2 panels and 4 ufo,)and 1000w of I-GRO led,(3 385w) in a 10x10x6

average room temp 82f
 
Icemud said:
I think on the Mars II, the fans are intakes, and suck air in, and blow it downward on the heatsink. I believe most LED's are designed this way.
Click to expand...

My 192x3s are the same way. The fans on top are intakes and blow air out the side vents. The fans are just 120mm computer case fans and could easily be flipped over to push air out of the top. I was thinking that if I did that, I could tape a register box to the top of the LED and use 6" or 8" ducting with a booster fan to extract most of the heat.

Can anyone see a downside to reversing the airflow of the fans?
:Namaste:
-Monkey
 
Hosebomber said:
They will be less effective pulling air through the case rather than pushing. It really depends on how hot your area is getting.
Click to expand...

Thanks for the input Hosebomber!

Its not that hot. With no air exchange at all and just leaving the vent socks of my tent open, I'm running about 7-12 degrees above ambient. Usually about 80-85 degrees at plant level in the tent.
 
My tents are currently empty and I just got my LEDs yesterday. I will definitely be adding more ventilation before I put any plants in there. In the meantime, I've been running tests to gauge temperatures. I'm still working out exactly how I want to do my ventilation, which is why I asked my original question. I'm just trying to think about it from different angles.

Thanks!
:Namaste:
-Monkey
 
Instead of air cooling any of my lights, including HPS, I cool my room down with air conditioning. To leave my small air conditioner on 24-7 at 70-74 cost me only $50 a month.

You could consider just using an air conditioner inside the tent. Use the kind that has ducting. I forget what they are called. They blow the hot air out the ducting and cool air out the vent. Set it to 78 and it wouldn't cost much electricity, especially in such a small space.
 
As an engineer, I'd worry about cooling the LEDs.

I am not an E&E engineer. As a horti, all that I'm worried about is regulating the temperature in the grow environment. LED units, as they are, add heat to a room while making it costly to isolate the heat extraction without sacrificing lumenosity as well as control over CO2 and humidity.

Be wary of cheap 5w LED units - they will only disclose recommended head rooms over the canopy after the sale is made. Larger units require 3-5 feet of space. Certainly not suitable for tent grows - partially because of intensity, and I suspect the heat generated by the lights. Do not ever assume LEDs are "summer lights", as they are no less easier to cool in comparo with HID.
 
Brolex said:
As an engineer, I'd worry about cooling the LEDs.

I am not an E&E engineer. As a horti, all that I'm worried about is regulating the temperature in the grow environment. LED units, as they are, add heat to a room while making it costly to isolate the heat extraction without sacrificing lumenosity as well as control over CO2 and humidity.

Be wary of cheap 5w LED units - they will only disclose recommended head rooms over the canopy after the sale is made. Larger units require 3-5 feet of space. Certainly not suitable for tent grows - partially because of intensity, and I suspect the heat generated by the lights. Do not ever assume LEDs are "summer lights", as they are no less easier to cool in comparo with HID.
Click to expand...

I run about 600 + watts of LED in a 5 x 5 tent. Running a 400 cfm ventilation fan at about 1/2 speed. Rarely have my temperatures run over 85 degrees even on the hottest days with just the central air as cooling and exhausting the tent into another room. My lights use 3 watt LED which are currently more efficient than a 5 watt LED.
 

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