CMH vs LED COB: The Differences Between Them, And Which Option Should You Choose?

Just like they did with displays, LED lights have become the real standard when it comes to illumination. You see them everywhere, and they are just as effective as they are ubiquitous. 

However, it really is one thing deciding to get an LED light – you also need to be aware of what you’re buying and make sure that it is the perfect fit for whatever it is you’re trying to achieve. And, considering that there are just so many types of these lights, it’s understandable that you might not even know where to begin. 

In this article, we’ll look into two of the more prominent LED types – CMH and COB – to see how they work and which option will be better for you to select, especially if you’re looking for a perfect grow light.  

CMH vs LED COB: What Are They, And How Do They Work?

Before we look into the comparisons for both, it might be a good idea to even get familiar with the concept of grow lights themselves. Basically, these are lighting options that are used when you’re trying to grow specific plants. 

If you think back to basic science class, you’ll recall that plants need light for photosynthesis. However, with the demand for food and other plant-based products going up, more people and companies have been looking for artificial light sources to essentially mimic the properties of the sun. 

That said, it is important to understand that you can’t just use any light to grow plants. This is because every plant will need a specific light wavelength to produce the nutrients it needs to grow. And, this is where grow lights come into play. Their job and unique makeup allows them to emit light in the right spectrum that supports the overall growth of plants, and as you can imagine, LED lights are part of that.

Understanding CMH Grow Lights

The “CHM” in “CHM grow lights” actually stands for “Ceramic Metal Halide.” This is a light form that comes with a high-intensity discharge and which bursts out a massive amount of light intensity. 

As its name suggests, the CHM grow light was built specifically for growing plants indoors. And, the funniest part is that CHM grow lights are relatively new to the scene. But, in a short amount of time, they’ve managed to take the industry by storm and really become one of the industry standards. 

With their broad spectrum, CHM grow lights offer a seamless balance between both red and blue light wavelengths. This means that they are perfectly able to emulate the properties of the sun and ensure that plants can grow properly throughout their cycle. Some of the properties that make these lights especially impressive include the following: 

  • Proper Lighting: When it comes to efficiency, a CHM grow lamp definitely ranks up there. Their output per watt is quite impressive, and the lights themselves are able to offer more functional light for plants compared to some of their competitors. 
  • Color Rendering Index: As you would imagine, the color rendering index (CRI) for a CHM grow lamp is quite on the high side. This means that a CHM light will be able to show the real color of objects that it lights up. 
  • They Last Long: You can also guarantee that you’ll get your money’s worth with a CHM grow light since it will last pretty long. 
  • Putting Out Heat: That said, one thing you want to keep an eye out for when it comes to these lights is the heat that they tend to generate. The heat level might not necessarily be so much, but it’s something you want to keep an eye on. 
  • Covering Every Angle: Another awesome thing about the ceramic metal halide grow light is that you can literally use it for every part of the plant’s growth and life cycle. So, that comes as a cost-benefit for you. 

CHM Lights Spectrum and Color Temperature

So now that we understand the answer to the question – what does “CHM” stand for? Let’s look at two critical aspects of lighting technology – color temperature and light spectrum. 

As we said in the previous section, the ceramic metal halide growth light shines across a broad spectrum. This covers different wavelengths that you can easily tweak and fine-tune to fit the requirements of whatever plant you’re growing. 

With a sleek combination of both red and blue wavelengths, the CHM grow light ensures that you can use it across every aspect of the plant’s developmental life. Now, while the specific spectrum will depend on the manufacturer and the bulb they choose to use, you can rest assured that this light does well to mimic the properties of the very sun itself. 

Moving on, we have color temperature. Essentially, this metric looks into the color of the visible light source by directly placing it beside that emitted by an on-reflective body. For CHM lights, there is also a broad range of color temperatures – usually falling around the 3000K to 4200K region. As expected, the lower the range, the warmer the light is considered to be, and vice versa. 

When choosing your bulb, it goes without saying that you want to consider the plant and its needs. But, this classification should help you understand the options better: 

  • 3000k: This is mostly what growers use when their plants enter that early flowering stage. It’s warmer, and it helps plants optimize both flowering and the development of fruits. 
  • 4000k: For this, you have a temperature that generally balances things out. It works for both flowering plants and those ones that are more vegetative in nature, and in many cases, growers can even use it for the entire span of the plant’s growth sequence. 
  • 4200K: Also relatively balanced, this wavelength also runs for the entire growth period. That said, it is much cooler than the other two, and this means that it would most likely be better for vegetative plant development. 

Now, it is worth noting that these are just guidelines. So, you would still need to consider the needs of your plant when choosing.

Exploring LED COB Grow Lights

The next option we have is the COB LED light. As we now know, “COB” stands for “Chip-on-board” – a form of lighting technology where you have different LED chips being placed directly on a singular substrate. With this lighting technology, you have a very compact, put-together lighting module – unlike most conventional LED lights where you have the chips being mounted on their own. 

Like CMH lighting, the COB grow light also provides a very high level of brightness overall. COB LEDs offer very high levels of light concentration, with their unique arrangement ensuring that they easily focus light on an object. And considering that plants need a lot of light to grow, you cam understand why this is so ideal. 

Besides this high concentration, however, there are several other features that these lights provide. Some of those include: 

  • Consistency In Delivering Light: Another interesting feature that comes from the unique arrangement of the COB LED is that it easily optimizes uniformity when it comes to distribution light. You want your plants to get light all through, and this is exactly what a COB LED grow light can offer. 
  • Choose Your Spectrum: Unlike traditional lighting options, COB LED grow lights make it possible for you to select the spectrum of light that you want. This makes it very easy for you to personalize the luminous output.
  • The Simple Build: Simplicity is always a desired trait when it comes to lighting options. And, this is something that COB LED grow lights excel at very well. With their unique design, they optimize space and are perfect for growers who don’t have much of that in the first place. 
  • They Last Long Too: At the end of the day, you want a lighting option that will be able to save you a lot of money. And, when you consider the functionality of these LEDs and the fact that they last long, you can see why they’re so coveted.

CMH vs LED COB: Energy Efficiency Comparison

Regardless of what you’re looking to do, one of the things you want in a lighting option is energy efficiency. Essentially, you need a lighting option that is able to make adequate use of your energy system and essentially optimize it as much as possible. And, this is where we really start our comparison between LED COB lights and CMH lighting

Light Output Per Watt

The first rung on this ladder is examining both options based on their light output per watt. On this front, it appears that LED COBs do better. 

Now, to be fair, CMH grow lights are more efficient than traditional lighting options like HIDs and more. However, the truth is that COB LEDs achieve higher light output per watt compared to the other option – in fact, you can find some COB LEDs that hit over 150 lumens per watt. That’s not to be toyed with. 

Controlling The Lighting Spectrum

When it comes to lighting and growing plants, you want to make sure that you have the right spectrum that caters to the needs of the plants themselves. Both COB and CMH LED grow plants allow you to control this spectrum to a considerable degree, but once again, COB LEDs come on top here. 

With their ability to help you tailor the output of light to your plant’s needs, COB LEDs also significantly contribute to the overall energy efficiency rating. 

How Much Heat Do They Spill? 

As we already pointed out in previous sections, LED COBs are the clear winner here. 

To fair, CMH LEDs don’t have a high heat output – especially when you compare them with several other traditional lighting options. However, in some cases, you might still need to implement proper heat management to get them working properly. This is a major issue that you just don’t get with COB LED lights. 

How Long Do They Last? 

With a CMH grow lamp, you have a lighting option that can easily work for anywhere between 10,000 and 20,000 hours. However, COB LED lights blow that number out of the water, providing functionality for as much as 50,000 hours. 

You won’t need to replace the bulbs and light fixtures as much as possible, and this will undoubtedly contribute to overall energy efficiency.

CMH vs LED COB: How Well Do They Convert Electricity Into Usable Light?

On the next front, we’ll look into the efficiency of converting power input into applicable, usable light. For this comparison, we look into metrics such as the Photosynthetic Photon Flux (PPF) or the traditional lumens per watt itself. 

So, with these two being the major yardsticks, how are COB LEDs and CMH LEDs able to effectively handle the comparison? 

For CMH grow lights, you usually get an efficacy between 80 to 110 lumens per watt entirely. However, if you move to the level of PPF, you will find that CMH lights usually stand in the 1.5 to 2.0 micromoles per joule range. 

On the flip side, LED COB grow lights have a higher efficacy compared to their counterparts. With a high-quality LED COB light, you can easily find well over 100 lumens per watt – and, some options can get even as high as 150! 

The same thing is seen with PPF values. With COB LED grow lights, you can get well over 2.0 micromoles per joule, and some options can get much higher. 

All in all, COB LED lights do very well here. And considering the fact that they already lead in most other metrics, this isn’t necessarily surprising. 

CMH vs LED COB: Spectrum & Light Quality

For plant-growing functionalities, there is no overstating it – you want to make sure that the light you choose has the right spectrum. CMH and COB LEDs definitely come with their distinct characteristics and strengths, each of which makes them particularly ideal for specific uses. So, how do they compare? 

How CMH Grow Lights Perform

With CMH grow lights, you have a pretty wide spectrum range that covers different wavelengths. And, because those spectrums share a significant resemblance to natural sunlight, you will find that a CMH grow light will significantly help to improve the overall planting experience.

We should also note the balance in color temperature. With a CMH grow light, you will be able to incorporate both cool and warm wavelengths, meaning that you get a more visually appealing lighting option. 

Finally, the CRI of these lights should also be noted. With their high CRI, CMH LEDs allow you to see the proper look of specific objects. If you’re looking to get a proper look into plant health and understand the different dynamics surrounding its growth, then these lights just might be what you need.

Metrics For COB LED Lights 

The first thing that LED COB grow lights have is the fact that they allow you to easily control the light spectrum you’re working with. As a grower, you can easily adjust the light output to seamlessly optimize the growth of your plants across different developmental stages. And, when you need to fine-tune the light to cater to the needs of specific crops, you’ll find that this comes in very handy. 

Next, you also have the opportunity to design your COB LED light to shine light in a particular wavelength range. As long as it is critical to the photosynthesis process, you shouldn’t have an issue. And, this targeting also comes with an energy efficiency benefit since it means you can cut down on the production of light that your plants don’t really need.

When you add these to the fact that you can find different color temperatures – usually ranging from 2700K to 6500K – with these lights, as well as their high CRI, you’ll find that COB LEDs are definitely high there on the CMH vs LED comparison. 

CMH vs LED COB: Which Is More Expensive?

As a plant grower, there is no doubt to the fact that you want to choose a lighting option that easily fits into your budget. After all, the entire purpose of this is to make sure that you don’t end up spending much more than you need to. 

So, with cost being a major determinant, how do you know which option to pick in the CMH vs LED comparison?

The Starting Cost

When you get to a dealer, you’ll most likely find that CMH LEDs are less expensive than COB LEDs. mostly, they’ve been in the market for longer – and, as they have become more available, their prices have also dropped.

We should also point out the fact that these lights tend to come with a lower feature set than COB LEDs. So, it shouldn’t come as much of a surprise that they cost less.

What Can You Get From them?

That being said, the fact that COB LEDs provide a higher feature set should definitely play and factor into your overall consideration.  

To be fair, CMH grow lights have a lot going for them. However, their higher energy consumption will be a major impediment to their adoption as it can especially lead to higher energy costs over time. With COB LEDs, you get greater energy efficiency, which means that you have an opportunity to offset those initial costs to a considerable degree. 

How Long Do They Last? 

As we already pointed out, COB LEDs last considerably longer than CMH grow lighting. As a result, you tend to get more value out of your money and will be able to significantly cut down on long-term costs. 

At the end of the day, it sure is worth overlooking the higher initial costs that you pay with COB LEDs. Sure, they cost more at the start – but, by the time you factor in the benefits you stand to make and the fact that you won’t even spend so much on maintenance, you’ll find that this initial cost is more than worth it. 

CMH vs LED COB: How You Make A Decision

So, it all comes down to this – what do you pick between these two lighting options, and how do you even know which option to go with? Here are some critical considerations for you going forward: 

Your Bottom Line

Of course, you can’t buy what you can’t afford. So, before you go ahead, look into the option that really fits into your pocket. Here, remember to prioritize quality as well – remember that an option isn’t necessarily the better one just because it’s cheaper. 

The Energy Efficiency Rating

You also need to consider the energy efficiency levels of the options available. In most cases, you’ll find that COB LEDs are much better, and this gives them a significant advantage overall.

The Quality Of Light You’ll Get

On this front, you need to consider two main things – the available light spectrum and the light quality itself. They need to be available for the right planting scenarios, and you need to be able to customize the lights to ensure that you have a proper output. 

Taking Out Excess Heat

Another important metric here will be to ensure that your chosen option can easily dissipate heat – or, at the very least, manage it properly. The very last thing you want is for the entire environment to get a little too hot because of your lighting. 

Their Expected Lasting Duration

You don’t want to end up spending so much time and money replacing your bulbs every now and then. So, be sure that whatever option you choose is able to last long. 

We already pointed out that COB LEDs do better in this regard. But, you also need to ensure that you’re getting your bulbs from a reputable dealer. 


At the end of the day, COB LEDs and CMH LEDs are great options for anyone looking to implement proper plant growing. However, by understanding the two options and your requirements, you will be able to make a steady choice. 

If you need any further clarification or need to get your hands on a reliable lighting option, then feel free to reach out to us at NSE LED Cloud. We’ll be more than willing to help you out. 

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