That's an old wives tale as well.
The heat generated by an LED fixture is actually harder to get rid of than an HPS. You can completely seal an HPS from the environment in a small tube and the tube is all you have to cool. You can't do that with LED fixtures. They're just too large and spread out.
Secondly, that "change your bulb every 6 months" myth only apples to industrial growers that grow round the fucking clock, 24/7/365.
For the small, personal use only grower like me, it's more like once every 3 years. Yes, years. Again the math for the non-reading:
Two bulbs - one HPS one MH.
The MH bulb runs about 20 dollars and is good for 10,000 hours. 18 hours on, 5 week veg = 630 hours per grow. You should replace the bulb about 65% through it's rated life, so that means you should replace it ever 6,500 hours. That means you are going to get 10 grows out of that one bulb. Or, in my case, about four years worth of service.
The HPS runs about 20 dollars as well and is rated at 24,000 hours. 12 hours on for 9 weeks on the average grow. That means you're using it for 756 hours per grow. Replace the HPS at 60% because they tend to drop off a bit quicker in spectrum than that MH bulbs do. That means you replace it at 14,400 hours. That means you get 19 grows out of one bulb or about 5.5 years in my case.
Everything said about power consumption and heat are basically myths cooked up by fangirls that bought a COB and have to make the most ridiculous arguments and bullshit they can to justify the expense.
There are really one three reasons to buy a COB:
- Money is no object and you simply don't care.
- You live in Hawaii (the power costs there are RIDICULOUS to the point COB's are a LOT cheaper to run.)
- You are a large licensed grower.
Larged licensed growers love COB's for the power savings. The costs when you start racking up 12 fixtures is a lot. What's more, since they're more efficient that often saves any additional need for power upgrades in a building that can cost you thousands of dollars up front.
That's it in a nutshell for about the 20th time.