Which bar lights emit the least heat?

I'm thinking lights that run the coolest are the most conducive to vertical growing on two shelves, one on top of the other. Shorter distance from light to canopy, less space. AC and fans help, but ... start cool, less effort to remain cool. That's been my experience.

Thread goal: a short list of recommendations. I can compare them (size, stats, price, diodes). I'm anticipating bar light suggestions, but am open to surprises. Seeking suggestions for lights you'd use in bloom, not shit Amazon lights or lights designed for veg/seedlings. Currently run 66" Fluence bar lights, they run pretty cool.

the one that uses less wattage.
one watt of power = 3.4 btu
One btu will raise temperature 1 degree per 55 cubic feet, so one watt will raise temps by 3.4 degrees per 55 cubic feet
these are immutable, unchanging laws of physics, there is no escaping it. all lights, of every type, emit the same amount of heat per watt...so do toasters, tvs, computers, water heaters....every electrical appliance anyone owns, anywhere emits 3.4 btu per watt used.
the advantage leds have is that they don't produce a lot of waste heat, like h.i.d. lighting does, metal halide and hps lights produce a lot of unusable spectrum, which is wasted as radiant heat, which is harder to get rid of, as it heats up all the surfaces it hits without really doing much of anything towards growing your plants.
so the balancing act is to run the minimal amount of watts that will give you the results you want.
with leds, i find that 35 watts per sq foot gives me good results, and that going up above that doesn't seem to make much difference, but others may have had varying experiences.

Apostatize said:

I'm thinking lights that run the coolest are the most conducive to vertical growing on two shelves, one on top of the other. Shorter distance from light to canopy, less space. AC and fans help, but ... start cool, less effort to remain cool. That's been my experience.

Thread goal: a short list of recommendations. I can compare them (size, stats, price, diodes). I'm anticipating bar light suggestions, but am open to surprises. Seeking suggestions for lights you'd use in bloom, not shit Amazon lights or lights designed for veg/seedlings. Currently run 66" Fluence bar lights, they run pretty cool.

Click to expand...

Check HLG for light specifically designed for racks.

Apostatize said:

I'm thinking lights that run the coolest are the most conducive to vertical growing on two shelves, one on top of the other. Shorter distance from light to canopy, less space. AC and fans help, but ... start cool, less effort to remain cool. That's been my experience.

Thread goal: a short list of recommendations. I can compare them (size, stats, price, diodes). I'm anticipating bar light suggestions, but am open to surprises. Seeking suggestions for lights you'd use in bloom, not shit Amazon lights or lights designed for veg/seedlings. Currently run 66" Fluence bar lights, they run pretty cool.

Click to expand...

What Roger said, watts = heat. Look for lights with higher efficacy, more light per watt. Many lie about efficacy and other specs so beware. I believe Grow Lights Australia is 3.0 or better and HLG is also, or soon will be.

I think Migro Aray should run cool. The driver is placed outside as well. He also recommends a pretty low positioning, 7'' or 18cm

From Migro website:

Driver and Lamp operating temperature

Both the led bar heatsink and led driver both operate at about 25 deg. C or 45 F above ambient temperature. So at 25 degrees C or 77 F room temp the driver and heatsink will be about 50 deg. C or 122 F. This is perfectly normal and safe.

Astral22 said:

I think Migro Aray should run cool. The driver is placed outside as well. He also recommends a pretty low positioning, 7'' or 18cm

From Migro website:

Driver and Lamp operating temperature

Both the led bar heatsink and led driver both operate at about 25 deg. C or 45 F above ambient temperature. So at 25 degrees C or 77 F room temp the driver and heatsink will be about 50 deg. C or 122 F. This is perfectly normal and safe.

Click to expand...

In my mind, I see, for example, a room where you can walk up the middle, surrounded on both sides by 2 levels of lights, separated by a divider/other light/liquid leak precautions. Probably all like 2" PVC shelving. Seems people assume they'd stack veg on veg, or bloom on bloom. To me, I'd try to stack bloom on veg because it would use less space than bloom on bloom. Veg on veg to max clone #s.

Top level bloom: 6 x 55" Fluence bar lights with ballast separated by a 6' cord. Six seems more manageable than 10+ bar lights together -- primarily, less heat.
Bottom level veg: 2 or 3 of the same bar light, but with dimmers AND, crucially, use the veg-specific ballast with 1/2 the amps. Plus fans....

You might put two of those pairings long-ways on one side, making 4 of those pairings in one room. Then, do it again in a second room. And max out any walk-in closet space with racks of seedlings/young clones.

But I'm sure there are more efficient brands.

Build your own with led with bulbs, space them 18cm, remove caps and make some reflectors with a reflective sheet.
They will last forever, just replace the bulbs every 2 years.

Roger A. Shrubber said:

the one that uses less wattage.
one watt of power = 3.4 btu
One btu will raise temperature 1 degree per 55 cubic feet, so one watt will raise temps by 3.4 degrees per 55 cubic feet
these are immutable, unchanging laws of physics, there is no escaping it. all lights, of every type, emit the same amount of heat per watt...so do toasters, tvs, computers, water heaters....every electrical appliance anyone owns, anywhere emits 3.4 btu per watt used.
the advantage leds have is that they don't produce a lot of waste heat, like h.i.d. lighting does, metal halide and hps lights produce a lot of unusable spectrum, which is wasted as radiant heat, which is harder to get rid of, as it heats up all the surfaces it hits without really doing much of anything towards growing your plants.
so the balancing act is to run the minimal amount of watts that will give you the results you want.
with leds, i find that 35 watts per sq foot gives me good results, and that going up above that doesn't seem to make much difference, but others may have had varying experiences.

Click to expand...

Thank god someone else understands elementary physics. I was trying to explain this to a mate the other day. He had a 100w quantum board in a 2x2.

The genius decided to switch to a 130w CFL "because they run cooler and you can have them closer to plants"

So he ended up with a hotter tent, far less light intensity, plus worse spectrum and less coverage.

It shouldn't be that hard to figure out that 130 is bigger than 100.

VincenzioVonHook said:

Thank god someone else understands elementary physics. I was trying to explain this too a mate the other day.

Click to expand...

Some people understand elementary physics, others understand proper word usage; a few understand both.

PJ Diaz said:

Some people understand elementary physics, others understand proper word usage; a few understand both.

Click to expand...

It's a give and take scenario lol. Can't have both can we.....well I certainly don't haha.

I searched for some keywords such as ''led grow light vertical farming racks'' and i found hundreds of pages, but they are all unknown lights to me at least. And most of them seem industrial/commercial, with no price for a single product, only asking for a quota for wholesale business i guess.

Are you looking for something like this maybe?

Astral22 said:

I searched for some keywords such as ''led grow light vertical farming racks'' and i found hundreds of pages, but they are all unknown lights to me at least. And most of them seem industrial/commercial, with no price for a single product, only asking for a quota for wholesale business i guess.

Are you looking for something like this maybe?

MechaTronix - LED Grow Light Products

MechaTronix has developed a comprehensive range of advanced LED grow lights for top lighting in indoor cultivation and greenhouses, interlighting for high wire crops, supplemental lighting for vertical greenhouse farming and top-notch vertical farming grow lights.

www.horti-growlight.com

Full Spectrum LED Grow Lights: Types of Grow Light Panel, Tube for Sale | EnliteHorti

EnliteHorti provides a full line of energy-efficient custom led grow lights for indoor plant growing solutions. Our professional led grow lights help saving more electricity cost and getting high-quality yields with high intensity, high output, high power, and high-quality features. Get a free...

www.enlitehorti.com

Vertical Farming — PRONORO

Greenhouse, indoor, vertical farm horticulture light. HarveLite LED grow light. Horticulture lights indoor greenhouse grow lights. Vertical farm cultivation lights. CC RACK leafy green, medical cannabis, lettuce. LED GROW LIGHTS. High light efficiency. Hight PPF output. PPFD for grow stages from clo

www.harvelite.com

Our Company - SpecGrade LED

SpecGrade LED is a manufacturer leader of horticultural, commercial, and industrial LED lighting.

specgradeled.com

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Sort of. I'm kind of reading a few threads together where growers have discussed adding far red at various stages v. just an indoor-specific spectrum v. supplementing with a light that enhances anthocyanin/pigment production. Basically, I really like the specific spectrums Fluence offers. Growers talk about combining far red and other lights. They often discuss lights in terms of efficiency, heat, and the marketing term "full spectrum." But if I phrase it as "beat or compare X lights to Fluence," thread commenters get distracted and I don't get helpful responses. Perhaps I was lazy about how I phrased my question.

I might end up paying more for Fluence, but I'd like to be able to combine their indoor, anthospec, and far red spectrums in a vert setup. So far, I've only used their indoor spectrum.

I guess I really just want to know if there's a company that basically offers similar spectrums as Fluence (including their 66" bar light dimensions) but perhaps more efficiently and at a lower price. To me, Fluence is the standard; but I know other brands beat them in particular aspects (e.g., efficiency/raw power).

Another way I could filter out some products is by having a better understanding of the difference between greenhouse and indoor spectrums. Some products with high efficacy #s are actually designed for growing in greenhouses. So, not apples to apples.

This site helped steer me about lighting and heat.

As clearly stated above, a watt is a watt and produces a specific amount of heat.

So then the correct answer to your question is the coolest light temp-wise will be the one with the highest efficiency.

HLG scorpions are rated 3.0 max efficiency as are a few others. So the lighting you would ideally want max efficency.

Drivers can be 90% efficient to almost max operating power, and can be mounted outside the area to minimize heat.

I personally think however that I would not concern myself if I found a good deal on any lights with a 2.5 efficiency or better. Cost to get the best is rarily worth the premium vs next best.

ComfortCreator said:

This site helped steer me about lighting and heat.

As clearly stated above, a watt is a watt and produces a specific amount of heat.

So then the correct answer to your question is the coolest light temp-wise will be the one with the highest efficiency.

HLG scorpions are rated 3.0 max efficiency as are a few others. So the lighting you would ideally want max efficency.

Drivers can be 90% efficient to almost max operating power, and can be mounted outside the area to minimize heat.

I personally think however that I would not concern myself if I found a good deal on any lights with a 2.5 efficiency or better. Cost to get the best is rarily worth the premium vs next best.

Click to expand...

Thanks. I guess I'm comparing everything to Fluence 66" bar lights.




Looks like my timeline to buy a house is being pushed up to April.... Currently, my 2 dedicated bloom tents are an experiment: ten 66" lights in one tent, six 66" lights in the other. Heat, yield, all things considered, I prefer units of six 66" Fluence Rays.

Although I'm open to HLG, here's my current game plan:

I want four (4) vertical grow "units." Each unit will be comprised of two shelves. Really, a floor and a top shelf/rack separated by oversized flood table and PVC pipes running across the top. Perhaps one 2" PVC pipe per light to make it easier. Supposedly, 3' of 2" pvc supports 28lbs w/o bending. I'm basing materials/rack design from there.

Top: 6 x 66" bar lights.
Bottom: 2 x 66" bar lights. One time, Fluence accidentally sent me a replacement ballast with 1/2 the amps as what comes with their indoor spectrum Ray. I figure, starting with 1/2 the amps for close-proximity veg lights might be easier than dimming a full-powered ballast.

The 66" Fluence Ray has a higher efficacy than its 44" or 22" models. the 66" light comes in just above 2.4. However, I recall their greenhouse spectrum has a value closer to 3 (but not that close). Thing is, the indoor spectrum has, for example, more red.

So, what I think I'm really considering is 1) the efficacy and 2) the specific spectrum design. Right?



Below are 4 of 6 Fluence spectra:

Is efficacy dispositive? What about the actual spectrum? One factor outweighing all others just reminds me of one of the many topics discussed on here -- for example, growers who swear by a precise percentage of amber trichomes for timing harvest. You feel me?

Apostatize said:

comparing everything to Fluence 66" bar lights.

Click to expand...

Spectrum is important but most are similar or offer a few choices so that usually is not the deciding factor for quality products.

Fluence is as high a quality as it gets you wont go wrong with them.

OSBuds said:

MyDLC - DesignLights

qpl.designlights.org

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Thank you!

I don't see why stacked vert grows aren't more common ... realizing bloom on bloom is more practical than bloom on veg (i.e., doesn't require wrapping in, for example, Panda Paper to block light), but bloom on veg could probably be done in a smaller space....

Based on my current trial setups, I'm not going to even need 4' from roof to floor, per shelf.
- 2" pvc pipes. 4 vertical on corners, 1 along each side at the middle. Schedule 40 should be sufficient, but if 80's available at a decent price....
- 2 thick/treated plywood boards (nothing on floor but flood tray). Thicker board would have to be at the middle for upper deck bloom. Top board really just has to support weight of lights, ballasts.
- lots of pvc connectors 2-way, 3-way, 4-way whatever, wherever. At base, probably put a 3-way (top receiver, 90 degree 2-way base) and put whatever's trimmed off at the footies to reduce likelihood of tippping. Tie/screw into wall of course.
- have to cut precise holes in plywood to insert poles, hold up via pvc connectors. Probably 1.25" to support width sides (~5').
- flood trays on each level.
- spray boards with Killz and/or line with Panda Paper.
- drill 2 holes in plywood per each side of a light bar, loop steel/aluminum wire and hang. Possibly add plastic liner to prevent liquid leakage to bottom shelf.

I think that could work!

Start with one, build another every six 6 mos. or so until 2 are dedicated-bloom and 2 are dedicated-veg.

Sounds really easy! And that's concerning, I must be missing something.

I must take issue.
Heat is energy, with various units: joules, kWh, btu.
The watt is a measure of power, which is total heat divided by time.
A watt-hour is approximately 3.3 btu and is a measure of heat energy.

So my answer to the question is, independent of the wattage of the fixture:
the ratio of waste heat emission to useful par emission. One can use either power or energy physics since the time factor cancels.

That would be the figure of merit I would use. It is nicely scalable too.