Comparison Tests

Best LED Grow Lights of 2021 Comparison & Review Test Using Laboratory Data

We're doing something no one has ever done before -- well, sort of. Each LED company who takes their craft seriously focuses on buying high quality components that will last a long time (read: not fail within 2 years) and have high efficiency/output ratings. To test LED grow lights comprehensively, you really need to send them to a laboratory that will will run the light through a battery of instrumentation. Each test from these companies is not cheap. For all the testing that we're requesting, the bill can run up to about $1,500 per light. This was no cheap endeavor, but we wanted to create the most unbiased, comprehensive, and informative comparison review test on the web. Therefore we needed to be using the best equipment available to do our testing.


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Ceramic Metal Halide CMH 315W Lamp Comparison Test Data & Review

Download the Zoomable PDF HERE: CMH_COMPARISON1.pdf

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Hey everyone Nate with Growers House here and we just wrapped up our test on 315 watt Ceramic Metal Halide Lamps. Were trying to tease out which lamp available in the market is the best for growing plants. I scoured the market and got my hands on every single 315 watts ceramic metal halide lamp I could, with the intended use of growing plants of course.

We ended up with 10 bulbs and from those ten bulbs we put them through a battery of tests trying to keep all variables constant except for one. Our aim was to record the spectrum of these bulbs and get as much data as possible - data we can then pass on to you. Data to help you to make a decision on which lamp is going to be best for your grow, whether its the best output, the right spectrum or just the best value. That decision is totally yours,  we just want to provide you with all the information that you can use to make an educated decision. But first, a lot of people don't know about ceramic metal halide lighting, what it is or where it came from. First, just looking at this lamp you can see it's pretty small and has a different kind of socket than the usual Mogul style socket and requires a specially designed 315 Ceramic Metal Halide Reflector and or an CMH Bulb Adapter and enabled to be able to use them.

I want to first and foremost lets clarify one point - CMH is NOT a Metal Halide Lamp. Most people think Metal Halide Lamp, "I know what that is.. ok this lamp is made for veg."

No, that's not true. Lets take a look at a Metal Halide Lamp. A CMH lamp has a different emitter than a normal metal halide lamp, which is built of Quartz.  Inside a CMH there is a ceramic component. So the difference is this - A ceramic tube is able to withstand much higher temperatures. Many manufacturers are saying the higher arc tube temperatures happening inside the lamp allow for more color stability, better lumen per watt ratios and effectively an all around better bulb in comparison to the HPS metal halide. We're talking about how many photons of light you're getting to your plant in the usable spectrum per watt of input, which is really the way you want to measure efficiency for your lamps.

CMH lamps burn just like a normal Metal Halide Lamp. There are salts inside of the arc tube that heat up to a high temperature and that give off a certain spectrum. But, since the salts inside a CMH are able to heat up to much a high temperature they're actually turned into what resembles plasma. Plasma burning at this higher temperature has the effect of providing a spectrum that is much wider and better than traditional HPS or metal halide lamps.

So that's why these ceramic metal halide lamps are so popular these days because people are looking for the little edge in getting every efficiency of their garden possible and to be honest, Ceramic Metal Halide is kind of the new wave of the future in terms of getting there. So let's jump into some of these results that we have I want to show them to you because we got a little data crazy, doing some different spectral analysis some bar graphs and of course some light layout measurements and we also came up with essentially our own graph of what we think the best value is for your garden in terms of overall output and price.


Starting off looking at the spectrums of these two different lights, really there are two categories of ceramic metal halide lights. Approximately 3,000 Kelvin and approximately 4,000 Kelvin, with the 3000 Kelvin you can see that most of the intensity of the light is focused around about 600 nanometer range, that's where its strongest and you see that like really Orangish almost Yellowish Hue you see along with HPS light, so that's why it looks a little bit Orange to your eye and you also see when you get up more towards the IR there's a pretty big spike there just north of you know close to north of 800 nanometers and then it drops off and there's not too much past 900 nanometers.


Now if we look at the 4000 kelvin spectrum you'll notice that it actually looks a little bit more full that's because the spectrum is a little bit more broad but when you compare these two, what you can't really see is that the 3k is more intense, but the 4k has a little more of a broad spectrum. So that broad spectrum you see is a little bit closer to like the I would say its peak is closer to around that 500 range and that's why you see the light a little bit more as like a white light or even what people call blue light which more resembles even like your metal halide and usually out of the 4200 Kelvin lights you will see a little bit more going into the UV range although when we did some testing we did see that UV is were actually pretty high and some other 3k lights as well.


For this test our measurement of UV is relative- by measuring the intensity of the light between 250 and 400 nanometers and that range is primarily going to be focusing on the UVA and UVB these lights give off. The light that did best in terms of UV was the Ushio 3000 Kelvin CMH Lamp which was a little bit surprising and then the next up was the Nanolux MaxPar 4200 kelvin CMH Lamp. So working your way down you'll see that the difference between the lowest bulb and the highest bulb isn't significantly great I mean these are relatively low numbers if you're thinking of par so I wouldn't say that these lights are a very strong UV performer but they do provide some UV indeed but the range between six and eight point six for light of this size actually you know 315 watts is actually really not that bad, but if you’re looking for max UV I'd say go with that Ushio.


We made our PAR footprints to show how this light performed in a Sun System 315 Watt LEC Fixture on 120 Volt so keep in mind the inside of that fixture has some pebbled aluminum in it.


Our footprints which show a center readings for five sizes. 1x1, 2x2, 3x3, 4x4, 5x5  and the par readings at each one of those points. Keep in mind the pebbled aluminum aluminum can kind of shoot light in different directions it can scatter it a little bit. So really when you're looking at this don't take the Center reading as gospel, really the most important thing is to take as many measurements as possible and in this case when we take the measurements of each one of those parameters and add them all up and gives you a much more well-rounded story of how well this lights producing in the whole I mean when you're testing lights on a very very scientific level like with the best instrument instrumentation available using an integrated sphere and you're measuring basically every single, I mean we're talking multiple thousands points you're measuring with here we're doing you no more than 30 so you can see if you're looking at the center I mean the highest reading that we all have any light here was the Phillips 3100 Kelvin CMH Agro Lamp and it was pretty consistently the best across most of the readings. Taking that into account you know take a look at this noting which fixture it's in so that's the kind of spread you're going to get but of course when we do our testing we try to hold every variable constant except for one and that's what we’re testing for which in this case would be the bulb. So we used the same balance same height same reflector in the same ten you know everything was held to a standard where we feel like it was getting a to the point where pretty scientific.


Our part charts graphs includes the sum of the perimeters of each one of the 1x1, 2x2, 3x3 and 4x4 but the one that I want everyone to pay attention to most is the sum of all par for the 5x5 print because that's the one that takes the largest sample size of measurements into account. From the results of the 5x5 you can see that the Philips MasterColor 3100 Kelvin CMH Lamp was looks like by far probably the best overall CMH bulb available. It had the highest reading of all the measurements for PAR and when you look at the 4200 Kelvin version of the Philips CDM Elite 315W bulb did the best as well you know I mean going into this if I had to have a hypothesis I would say that Philips Elite 315W Brand would be my guess for the best bulb. Probably because Philips is company that designed and developed the 315 CMH lamp originally, perfected what kind of ballast to use with it, how it would work properly and their compatibility of the two both in Hertz and the wave type of the ballast so I would say kind of no surprise there.

Although it is a little bit surprising that Philips Ceramic MH Lamps did approximately eight percent more than the next best bulb which would be the SunPulse CMH 3200 kelvin bulb. The differential between the Philips CDM Elite 315W bulb @ 4200K and the next best 4200 k lamp looks like the Nanolux Max Par 4200K CMH Lamp is just under five percent.

We hope you can take these readings use them to make an informed decision on purchasing the best 315W light for your purposes you know 315 watt ballast and are relatively similar so which one you go with won't probably have a huge differential but it looks like these bulbs you can tease out that there are some differences so use the one that other was the most you be or the most intensity or the best spectrum with this information and if you have any questions for us please give us a call or send us an email and other than that, this is Nate from Growers House. Happy growing.

Download the Zoomable PDF HERE: CMH_COMPARISON1.pdf>

1000W Double Ended MH Comparison Test

1000W Double Ended MH Comparison Test


Video Transcript:

"Hey everyone, Nate from Growers House. We're doing our newest review test which is the Double Ended (DE) Metal Halide (MH) [1000w] shootout. There are two companies in the space. We wanted to see what they had to offer, what their spectral distribution looks like,  so we can really compare these lamps against each other and go over the pluses and minuses of both. There are two companies in the market at the moment (for MH DE), MaxPar which is engineered and distributed by Nanolux and then Solis Tek. If you take a look at these two lamps, you'll see they look quite different.

DE MH Lamp side by side at growershouseSolis Tek on the left, Nanolux MaxPar on the right. These are both 1000 watt Metal Halide (MH) bulbs. Both in the 4K versions. What you'll see here is that the Solis Tek doesn't have whats called an outer jacket that Nanolux Maxpar has on their double ended metal halide lamp. This outer jacket is something that's completely new, patent pending design by Nanolux and their engineers. MaxPar made this outer jacket because they wanted their bulb to ANSI and NEC standards. Sometimes when metal halide bulbs go out, they burst, and so they wanted this borosilicate glass over the quartz to make sure you're protected in that way. I talked to Solis Tek about that and they said they designed their bulb--even though it doesn't have the outer jacket--that it is safe to use.

Mainly when we're talking about safe to use we're talking about open rated fixtures vs. closed fixtures. Closed fixtures are like your normal air cooled fixture that has a glass lens that totally keeps the bulb enclosed. Whereas something like a Gavita or a Solis Tek A1 Double Ended DE Complete Light System 120/240V are reflectors that doesn't have any glass is an open rated fixture. We at GrowersHouse ran both of these bulbs in both style of reflectors, they are both quality bulbs, both companies recommend you can use them and in either open or enclosed fixtures they just have a different way of going about it.

maxpar4k_DE-MHNow when we test these I would imagine that some of the features are little bit of give and take. What you might gain in a little bit of safety on the Nanolux MaxPar double jacketed design (we will see under our spectrometer) but we'll see if that design changes in either the spectrum or the intensity. It could be a bit of a trade off.

So that's why we're here to really figure out today and will bring out all the bulbs in their entire lineup. Solis Tek has a 4K, 6K, and a 10K. Nanolux MaxPar has a 4K and 6K. When we say "4K" we are refering to Kelvin. The Kelvin scale (Color temperature of mesured light energy. Higher the color temperature the closer the light source is to the blue end of the spectrum. The lower the Kelvin temperature the closer the light source is to the red end of the spectrum).

The 4K lamps you can use for vegetative growth but you could also use for flowering. It's a little bit of one size fits all bulb. Whereas the 6K is a dedicated vegetative bulb that gives you more of a blue spectrum that's much better for a plant to have shorter inter-nodal spacing for its leaves and offshoots and at the same time give you a little more foliage and growth so your plants have more node sites for flowering.

SolisTek 10K DE LampSolis Tek has one added lamp selection, the 10K Finisher made for the end of flowering. Solis Tek recommends using this the last two weeks of flowering because there's a high amount of UV. The high amount of UV is going to mean that when you measure PAR (which is the intensity within normal realm of wavelengths that plants use to photosynthesize) the UV doesn't show up there. If you measure the 10K bulb under any PAR meter it's going to be quite a bit lower intensity than your normal for 4K, 6K, or HPS. Where it makes up for that is a little more intensity in the UV range. This 10K lamp at the end of flowering stresses out the plant's a little bit but it's a good type of stress because it causes plants to produce more essential oils which is what a lot of people are looking for. Lets see our test results.

DE  MH Test Spectra Graph

Looking at the spectral charts of these bulbs first we'll start off with the 4K. You'll notice that both of these bulbs are giving off the same spectrum (4,000 Kelvin) mainly for vegetative growth but can also be used for flowering. You can see that they closely match each other and if you look at the spectrum is really you just see that some points the SolisTek just eaking out the MaxPar little bit, but actually in a few other peaks the MaxPar has the highest point we would say these are very evenly-matched spectrum's.

DE  MH Test Spectra Graph

The 6K charts show similarity also, but you see the SolisTek and MaxPar peaking in different areas. The highest peak at about 590 nm is the MaxPar just a little higher than the SolisTek and in some of the lower blue peaks the SolisTek is eking it out. But overall you can see how these spectrums are very similar. If you go over to the UV all the way on the left you can see that's where that at 350-400nm around there you can see the SolisTek is eking out the MaxPar just a little bit but really these pictures are so similar.

DE  MH Test Spectra Graph

The Solis Tek 10K Lamp you'll notice over at 350-400nm the UV is much higher than the 6K which is what we would expect this is a finishing bulb made to have really high UV.

DE  MH Test Spectrum Chart

For these bulbs, so we measured the intensity of not only the normal light but also of the UV. Just as the spectral graphs showed, the intensity of the UV spectra for that 10K is up and above all the other bulbs quite a bit of at 43. Versus the other bulbs which are down, the 4K 6K are about 26 umols, and the MaxPar 4K at 23 umol and the MaxPar 6K at 21 umols. SolisTek did a little bit better in the UV but they're pretty close within a 10 to 20 percent difference in the MaxPar Nanolux.

In the lower portion the overall intensity that's where it actually flip flops a little bit with the MaxPar giving out overall slightly more intensity in the PAR which is the 400-700 nanometer wavelengths that plants use lights most efficiently to photosynthesize. Where the 4K SolisTek was at 1106 μmol the 4K MaxPar 1120μmol. The 6K SolisTek was at 950 μmol the 6K MaxPar at 1052 μmol so a little bit of a greater difference with the 6K than with the 4K that was very close.

The 10K is down at 925 μmol, this is an important thing to notice, that 10K down at 925μmol has a lot of its energy focused on spectra that's outside of the 400 to 700 nanometers range. Namely some of that UV and IR really are focusing on the UV in the sub 400 nanometers that's why you see the intensity of the umol go down there.

These are really interesting findings, we hope it helps you choose a lamp that's the best for your operation based on UV light and intensity. Both the Solis Tek and the Nanolux MaxPar MH bulbs can be used in basically any DE Double Ended fixture at this point.

If there's any other information you'd like to see please send us an email at

-Happy Growing!"

Double Ended Metal Halide Graphs Master Data Excel File *Click Here To Download*


4 Best T5 Grow Lights Comparison Test and Review of 4' x 8 Bulb T5 HO Fluorescent Fixtures

Hello my fellow growers, Nate here and we’re just finishing up doing a new test that we’re going to post that I was very excited about of T5 HO fluorescent grow lights. Even though they might not be considered the coolest lights in the industry, T5 four foot eight bulb high output grow lights. We’ve been wanting to do this test here at GrowersHouse for a long time because there are tons of people that ask us “Which T5 fixture is best? Which T5 8 lamp grow light is the best to use? Which T5 grow lights gives you the best spread? Output?” We finally got all the lights in house, ripped them out of their boxes, put them under our lighting footprint the five-by-five. What we did was essentially put the same t5 6500k bulbs in four different T5 HO grow light fixtures.


We used the Grow Crew 4 foot 8 bulb T5 fixture (now updated to Prism Lighting Science with 120v/240v/277v all-in-one), the EnviroGro 4 ft 8 bulb T5 fixture, the Sun Blaze and the Quantum BadBoy 4 ft 8 bulb T5 fixture. We had our suspicions of which fixture would do best and you’ll see in the testing below that the Quantum BadBoy fixture actually has a really awesome spread. But the things to really watch out for is that there are different scenarios for theses T5 Fixtures that that could produce higher output but we also noticed that the ballast driving them were also running at higher wattage.


We actually did some of our own calculations to figure out what we considered an efficiency ratio. You’ll see those ratios in the PDF here: click me.


By looking at this testing you can really see exactly how much wattage these fixtures are drawing from the wall, exactly what the amperage is, and exactly what the footprint is. Really the only difference in these fixtures is that they have different ballasts and different reflectors but we used the same exact bulbs (link) for each fixture. We just took the bulbs out of one fixture and put them in the next so we can keep that variable held constant, and these are in the exact same space using all the exact same power.


This test is very enlightening if I do say so myself. If you have any feedback leave them in the comments below. We’re also going to be testing out T5 Bulbs here in a second especially with the introduction of the new Hortilux Power Veg T5 Lamps so keep an eye out for that.


For that we'll change out a whole bunch of different T5 bulbs in the same fixture to see which T5 bulbs are really the best ones. These fixtures are used for vegetative growth primarily and seeing which fixture had the best spread really helps us figure out how we can put these fixtures in our vegetative growth areas so that we have good even light and we’re getting the most out of those t5 fixtures.



So first off before we get into showing you the PAR footprints of the fixtures I wanted to show them, or show you guys what the spectral output of a T5 high output light.

Now looking at this spectral graph this is actually a Grow Crew High Output (HO) 4' T5 54w Bulbs - 6500K and you can see that the spectrum is relatively broad actually. You got reds, yellows, even some greens, blues and some deep blues.


T5_PAR_FootprintsSo this is what the spectral graph looks like of a high output 54 watt T5 bulb, now jumping into the fixtures you’ll notice at basically every PAR footprint the intensity is a little more uniform wide than it is long and that’s to be expected with these fixtures because the reflector kind of diverts the light to go left and right rather than the long way, (wide instead of long). This is a really good fact to know because it can help out in mapping out your grow room. You don’t need as much cross lighting going sideways from the fixture as you do longitudinally.


Stacking these fixtures up against each other you can see that there wasn’t a huge variance. We’re probably talking only about a difference of about 10% (about the outside perimeter) but once you get towards the center the difference between the least intense and the most intense unit is about 20% from the Grow Crew to the Quantum BadBoy. (Measured at 24 inches above)


Other than the Quantum BadBoy the fixtures were pretty similar like the EnviroGro, SunBlaze and Grow Crew fixture were all kind of neck-and-neck. It depended which area you measured on which fixture does best but the Quantum BadBoy stood out quite a bit and I think that is because the ballast is driving more wattage to the bulbs and the reflector is actually larger and the reflective material inside of it seems to be a better quality.


One note here is that only the Quantum BadBoy T5 and Grow Crew T5 (updated to Prism Lighting Science) T5's can run on 240v, and only the Grow Crew fixture can also run 277v. All other fixtures run only on 120v.


You’ll even notice that there’s kind of an arbitrary ratio that we came up with but take it for what you will, but we wanted to show it off anyways. It is the PAR over watts ratio, you could consider it somewhat of an efficiency ratio or like how much light output per watt, and you’ll notice that the Quantum BadBoy again did best out of all these fixtures. So if you’re looking for the best unit out there, I’d say the Quantum BadBoy is definitely it. Other than that this is Nate from Growers House, stay tuned for more tests. Happy Growing!

Best T5 Test Results PDF Here: click me


What Indoor & Greenhouse Grow Light Fixtures Are Most Economical? A Look at the Bugbee Model

Crop scientists at Utah State University recently released a study that is generating a lot of buzz in the indoor gardening, hydroponics, and greenhouse market. The scientists measured the photosynthetic (400-700 nm [PAR range]) photon efficiency and photon distribution patterns of double-ended HPS lights, LEDs, Fluorescents, Induction, Ceramic Metal Halide, and standard mogul base HPS lights [they measured popular indoor garden lights such as the Gavita Pro 1000w Complete Double Ended, ePapillion 1000w Double Ended, LSG Violet, SPYDR 600, LSG red/white, Illumitex NeoSol 300w NS, Lumigrow Pro 325, California Light Works Solar Storm 400, Black Dog BD360 Universal Series, Apache Tech AT120WR, iGrow 400w Induction Light, Lumigrow ES 330, and HydroGrow Sol 9, Cycloptics Ceramic Metal Halide, Fluorescent T8 fixtures, and mogul base 1000w HPS fixtures]. The study also took initial cost of the fixture and electrical costs to conclude that LED and double-ended HPS lights were the most efficient lights out of the bunch, with double-ended HPS slightly ending out LED.

The way this test calculates the economics of a lights efficiency is by factoring in the initial capital cost of a fixture and the cost of electricity to operate it over a 5 year period and comparing that to the amount of photosynthetic photons (light that plants are known to use to photosynthesize) they deliver.

Over a 5 year timeline, the study found that when you factor in electricity and fixture cost per mole of photons, LED lights are approximately 2.3 times more expensive than HPS fixtures to operate. This brings about another interesting question, which is how will that multiplier of 2.3 change as LED technology keeps progressing? As LED technology keeps getting less expensive and more efficient, by what year will that 2.3 multiplier dip below 1 making LEDs more efficient to run than HPS lights, in turn totally changing the standard for indoor grow lights from HPS to LED.

The hard part about doing a test like this is that measuring light efficiency can never be absolute. What I mean by that is that there is no one light that does everything a plant or specific garden setup needs. Some plants grow larger and taller than any one fixture can satisfy, and some are small enough that much light may go unused. Also, garden setups may have long skinny rows, or may be designed in some way that's completely different. For example, LED lights have optics that can be manipulated to have a specific coverage area, while HPS lights need reflectors to perform that function, and reflectors are often less precise. So although this test found that LEDs are more expensive over a 5 year period when all emitted photon radiation is assumed captured by plants, when a more narrow region is considered to be captured below the fixture (for example on flood tables or benches) some LEDs in the test actually had a lower cost per photon than HPS fixtures. So a HPS light emits more light, but the LED lights have the potential to be better at taking their energy input and directing it over a small, specified region. Results like this don't make choosing a light quite as easy as we had hoped.

We have to remember when looking at studies like this that they don't tell the whole picture for most of us indoor growers, and we can't expect it to. Tests like this need to set parameters, assumptions, and measure variables accurately. Throwing more variables into the equation, such as cooling the environment and its associated costs, throws in added complexity. If you're feeling extra nerdy, read through the PDF of the academic write up below to view this information in all its detail. We look forward to more universities providing insightful information like this to help us make important purchasing decisions for our gardens rather than having to rely on marketing claims, which can often be misleading and inaccurate.

Lastly, one of the coolest and most useful things to come out of this test is a cost calculator that helps you compare light fixture cost over a 5 year period. A great resource that you can download here: Five-Year Cost Calculator for Grow Light Fixtures Excel File

This is Nate from Growers House. Happy Growing.

Bugbee - Economic Analysis of Greenhouse Lighting_ Light Emitting Diodes vs. High Intensity Discharge Fixtures PDF Download