That difference is that the cylinder that contains a mixture of metal halide gases is made of ceramic rather than glass as it is with your standard metal halide bulb. As a result because it’s ceramic it can withstand higher temperatures, about 300° higher.
So as a result of its ability to withstand higher temperatures there is a lessening of the degrading of the gas tube surface that you get more prominently with a standard glass to tube. The little glass tube that’s inside the larger glass outer casing.
So the first benefit is a longer service life because it’s this degrading of the gas tube that determines thew service life of a lamp. Ceramic doesn’t degrade as fast, so it lasts longer and as a result you get a longer service life.
Then along with the less clouded and bubbled up gas tube over the service life of a ceramic metal halide the light passes through better. This in turn leads to more efficient light output output because light passes through clear glass better than it does clouded glass.
They also produce more light as well in a broader spectrum, so you can use the same bulb for the vegetative as well as a flowering cycle without having to change out and switch to a mercury vapor lamp when your plants start to bud.
Ceramic metal halide bulbs also burn a little cooler. Not a whole lot cooler but ‘any heat reduction’, particularly for someone growing in a confined space is good. Or if you’re growing in a warmer climate or limited with regards to your venting.
Then there’s one other benefit that comes with this bulb and that is that a ceramic gas containment vessel lowers the risk of catastrophic failure, (the bulb blowing up). It’s a rare occurrence but it can happen but due to manufacturing flaws or using a light after its service life has expired.
When this happens not only is there physical danger of someone being hit with flying glass but if a grower isn’t around when it happens there’s also the risk of fire. Now granted these risks are remote, but it does occasionally happen.
Now the downside here is that you are going to pay more for ceramic metal halide bulbs, this considering that standard glass tube bulbs have gotten pretty darn cheap in recent years. On the plus side though, you can use your standard ballast as long as it’s not a digital ballast.
They can’t handle the frequencies produced by a digital ballast but this rule isn’t chiseled in stone. This is because there is a digital ballast on the market now that will work for ceramic metal light bulbs but it’s expensive. Even so as time moves on more will come along and prices will eventually come down.
Then finally, even though manufacturers are working on it and have promised to remedy the problem HID ceramic metal halide bulbs are only available in lower wattage sizes. So you’re not going to find a 1000 watt bulb just yet because it looks as though the 400 watts is about as high they go right now.
The Bottom Line
Ceramic metal halides do have a longer lifespan but you have to pay extra the longer life span, so in this case in comparison to standard metal halides the point is moot.
They do produce a broader light spectrum with a higher amount of light in the blue and red spectral range which makes for a better grow bulb. A definite plus over standard metal halides.
Ceramic metal halides also do away with the risk of explosive catastrophic failure that comes with standard glass tube bulbs. Granted the risk is low, but nonetheless it does exist.
They also burn cooler but you need to be aware that the differences isn’t huge. Even so they do put off less heat and for someone growing in a confined space it can can make a difference.
400 watts seems to be the max that you can find on the market right now for this particular style of light. Manufacturers are working on bringing out higher wattage bulbs but none have appeared on the market yet.
