cost to opperate MH Vs LED

[alton]

Originally Posted by animalkingdom

do you use the double ended or single ended ones that last that long?

For me it has been single ended that have lasted up to 24 months and that was with only a 10% drop in PAR. You could not tell the difference in the 16 month old, 24 month, or 2 day old lamp which was which just by looking at all three on my tank.

[atreis]

Originally Posted by LobsterOfJustice

To be fair, operating cost of LED should also include the cost of running the heater more as well. I run a 1/2 hp chiller which sounds like a lot, but that is still around 400w. That's less than the amount of heating I run (500w). So really, if I switch to LEDs and need to run the heaters more in the winter, that's even worse than needing to run the chiller more in summer with halides.

Obviously, only during the winter, but ...

This one is a wash: You have the heat the tank somehow - whether you heat with MH or a heater, it's still electric. It would reduce the effective energy consumption of the MH, but not of the overall system.

e.g. Let's assume for a minute that heating with MH is 25% efficient - in other words, 25% of the electricity going into the MH bulbs is actually converted to heat within the tank. (BTW, I've absolutely no clue what the real number here might be). That means that if you have 500W of MH, 125W of that displaces 125W of electricity needed for operating a heater.

Given the above, if you go with 200W of LED (and let's assume they put 0% of their energy into heat in the tank - another completely fabricated number but it makes life easy), or 500W of MH, and let's assume there's a 300W heater, and that if there is no heat provided by the lighting it will operate for 3 hours a day (another fabricated number):

MH:
500W for 8 hours = 4kWH (light)
lighting puts 1000WH (8*125W) of heat into the tank - no need for heater
Total: 4kWH

LED:
200W for 8 hours = 1.6kWH (light)
300W for 3 hours = .9kWH (heat)
Total: 2.5kWH

Let's assume for grins that one uses a 700W chiller and it's able to remove 500W of energy per hour, and that without any light consideration it would normally operate for 3 hours a day during the summer to remove ambient heat. (Another set of completed fabricated numbers. We'll leave out the household AC to keep things simple, but obviously that would just increase the energy needs, where applicable.)

MH:
500W for 8 hours = 4kWH (light)
700W for 3 hours = 2.1kWH (ambient cooling)
700W for 2 hours = 1.4kWH (1000WH of heat added by lights)
Total: 7.5kWH

LED:
200W for 8 hours = 1.6kWH (light)
700W for 3 hours = 2.1kWH (ambient cooling)
Total: 3.7kWH

Spring and fall would fall somewhere in between. Plug in your own numbers and fiddle at will... Things I suspect everyone would agree on: less lighting wattage is needed for LEDs than MH, and substantially less heat is added to the water by LEDs than MH.

[LobsterOfJustice]

Originally Posted by atreis

Obviously, only during the winter, but ...

This one is a wash: You have the heat the tank somehow - whether you heat with MH or a heater, it's still electric. It would reduce the effective energy consumption of the MH, but not of the overall system.

e.g. Let's assume for a minute that heating with MH is 25% efficient - in other words, 25% of the electricity going into the MH bulbs is actually converted to heat within the tank. (BTW, I've absolutely no clue what the real number here might be). That means that if you have 500W of MH, 125W of that displaces 125W of electricity needed for operating a heater.

Given the above, if you go with 200W of LED (and let's assume they put 0% of their energy into heat in the tank - another completely fabricated number but it makes life easy), or 500W of MH, and let's assume there's a 300W heater, and that if there is no heat provided by the lighting it will operate for 3 hours a day (another fabricated number):

MH:
500W for 8 hours = 4kWH (light)
lighting puts 1000WH (8*125W) of heat into the tank - no need for heater
Total: 4kWH

LED:
200W for 8 hours = 1.6kWH (light)
300W for 3 hours = .9kWH (heat)
Total: 2.5kWH

Let's assume for grins that one uses a 700W chiller and it's able to remove 500W of energy per hour, and that without any light consideration it would normally operate for 3 hours a day during the summer to remove ambient heat. (Another set of completed fabricated numbers. We'll leave out the household AC to keep things simple, but obviously that would just increase the energy needs, where applicable.)

MH:
500W for 8 hours = 4kWH (light)
700W for 3 hours = 2.1kWH (ambient cooling)
700W for 2 hours = 1.4kWH (1000WH of heat added by lights)
Total: 7.5kWH

LED:
200W for 8 hours = 1.6kWH (light)
700W for 3 hours = 2.1kWH (ambient cooling)
Total: 3.7kWH

Spring and fall would fall somewhere in between. Plug in your own numbers and fiddle at will... Things I suspect everyone would agree on: less lighting wattage is needed for LEDs than MH, and substantially less heat is added to the water by LEDs than MH.

What? You literally just made up numbers and a scenario, and came to a conclusion. Additionally, you have underestimated the heater wattage and overestimated the chiller wattage. A 700w (1hp) chiller is rated for 250-700g depending on manufacturer, but a 300w heater is only rated for 50-150 gallons. Your scenario is completely unrealistic to skew the numbers in your favor. I know you probably didn't do it on purpose, but this is exactly the point I am trying to make. People underestimate heating and overestimate cooling.

Here's my scenario:

500w of MH and a heater not running during the day - compared to 200w of LED and 500w of heating running intermittently throughout the day.

It's pretty simple and this will be my last post on the subject. But it's just not fair to only cast the heat generating of MH as a negative, when the average person runs more wattage of heating on their tank than cooling anyway, and really could use that extra heat for half the year.

[Mike S]

One of the new interesting features of the new Apex Fusion interface in the current graphs which provide an average current. While not directly applicable to this discussion I recently switched from running 8 80 watt t5 bulbs to 3 250 watt MH bulbs and 4 80 watt T5s for dawn/dusk effect. Even though I'm running more wattage in lighting its obvious that my two 400 watt heaters are running a lot less. My average current has dropped slightly from around 9 amps to the lower 8 range.

It would be interesting if someone using Fusion did the switch from MH to leds and we could see what the energy usage different really was.

[john08007]

mike, that is interesting, when I started this thread I didn't think this was going to be so polarizing. I thought my MH's were incredible inefficient because of the heat produced in the ballast and lamp, I figured an LED was a lot more efficient. I never took into account the idea of not needing my heater as much. I also never knew that people had trouble with their corals growing under LED, as far as for me I think I am keeping my MH lamps

[Mike S]

Everyone's systems are a little different. Some people are in areas with high electrical rates and/or have heat issues where cooling tanks become necessary. For them the move to leds may result in significant energy savings.

I was a little hesitant to go with MH for fear that my electric bill would climb significantly. Once I started to do the math it became obvious that wasn't going to be the case.

[atreis]

Plug in your own numbers. The numbers will change, and the difference between them will change. You might be able to show a scenario where you end up being (slightly) better off with MH than LED during the winter. Overall though, winter, spring, and summer, you won't be.

[shifty51008]

ok I run 500 watts of MH and even during the summer my heater (500 watt) still kick on, during the winter I actually have to add an extra 250 watt heater or my temps will go down.

I am betting "IF" I were to ever switch to LED I would be using more watts in heaters than I am now just on lighting, so LED would actually be more costly to run in my case.