HID MH,HPS replacement w/ LED


I have a 18 year old Sunsystem dual 400w HPS and 400w MH setup with a magnetic ballast. It’s probably consuming 1kw of energy at least. The lamps get the room toasty and I have had a difficult time maintaining temps. Does anyone have suggestions of what an equivalent LED replacement would be?


@dbrn32 @MAXHeadRoom @Hogmaster @Donaldj @bob31 may be able to offer some insight.


Quantum boards are currently latest and greatest, if you don’t mind assembling a kit (fairly easy) I think you get into something that would probably be a little better than the 400 for about $350. Otherwise the assembled light that size is about $500. There are some really good cob fixtures in that price range as well. Other than that, you can get into a couple of panels from amazon for probably $200 or so. Obviously savings come with less performance, but plenty of people growing good weed with them.

What size room and grow methods do you use?


The room is a converted shower, floor is 33x46, 7’ tall. I am using soil, flower power fertilizer, and have been running both the 400w hps and 400w mh simultaneously at 18/6. I am growing autos and have plants of varying age


I see. Are you looking to replace them both and have led to cover the whole area? Or just have one? The light I recommended is going to have a little more par than a single 400 hid. But it’s not going to have the footprint of both. If that makes sense.


@dbrn32 I was looking to replace them both if an equivalent footprint with lower wattage, if that exists exists. I am trying to see if there is something more efficient.


There’s plenty out there that will get you more efficiency. What kind of budget are you hoping to stay within?


I’m going to attach a video, if you think you can assemble these I really think 3 of them would be your best bet for your size area. The issue I’m running into is that your shower is slightly different than the standard size grows of 2x2, 2x4, 3x3, or 4x4. The kits are like $185 each for the 135 watt, I know growers house offers them assembled and tested for an extra $25. You could probably do pretty good with two boards, but three is going to put you where you want to be. Probably the equivalent of two fresh 400 watt hid while drawing just over 400 Watts total.

If that doesn’t sound feasible, you could go with a fresh 600 my/hps combo. 315 lec will outperform a 400 mh/hps too, it’s just a little stretch for one and not really enough room for two. Or you could probably throw a couple of mars 600 or equivalent in there for around $300. But if you’re looking for the most efficient the quantum boards is where you want to be.


@dbrn32- thanks,you have give me a lot to consider here and to look into. This will get me going in the right direction.


No problem! If you need anything else tag me, I usually check in a few times a day.


My 400 watt HPS bulb was running at 133 lumens per watt. My LED COBS run at around 200 lumens per watt but I have drivers that are only 83% efficient, so I am getting about 166 lumens per watt when you count the drivers. Driver efficiency is very important! If you have 95% efficient drivers, then they could be about 1.4 times better than HPS.

HPS is more efficient than MH, so LEDs would be higher than 1.4 times more efficient than MH.

That works out to an electric bill that’s about 72% of the old one.


I found that most people still use lumens other than PPDF to compare the lights.

There is a wiki page about it:

I think after comparing the PPDF, most people will know that HPS is better than most LED lights in the market now.


Not necessarily. I think most people are just going by the manufacturer’s “equivalent watts” number and run too few LED panels. Then they are disappointed with low yield. If you replace your HPS lamp with LEDs having the same number of watts drawn from the wall, you will be surprised.

Par meters have a big problem: They take light readings at several different wavelengths, multiply each by a correction factor, and then sum them all. That is fine if the light source is sunlight. It has a known spectrum so PAR readings can be compared. But if your light source is only blue LEDs, your PAR meter would use the same algorithm and give you a sum reading, completely ignoring the fact that there is no red! Running your blue LEDs at 2x would have the same PAR reading as a nice spectrum at 1x intensity. PAR readings have some conversion factors for cool white fluorescent, CFL, MH, etc. But they don’t even try with LEDs because your LEDs could be any spectrum!

I think it would be more useful to just take a lux reading in the blue part of the spectrum and a lux reading in the red part, and report the two numbers.


hey! I have two dimgogo 2000w lights so far for a 60-70 clone room i am setting up, hydroponics, I am looking to at least or close to 1 pound per plant. any help on the light ? what i need?


What’s the size of the rooms?


About 50 true watts per square foot if you get run-of-the mill LEDs off Amazon. 35 watts per square foot if you get good high-efficiency strips, boards, or COBs from Timber, HLG, RapidLED, and such. They cost more but you save it in electricity over a couple of grows.