LEDs and electricity savings

[sphelps]

Originally Posted by kien

TRANSLATION: LEDs can save you money (but it also might not).

Yes

Originally Posted by mrhasan

Correction: LEDs can save you money (but it also will not)

No

[mrhasan]

Originally Posted by sphelps

No

Then why this line?

PS, I didn't get the Mitras to save money and personally don't think you should buy LEDs for the purpose of saving money cause in all reality you probably won't save anything But that wasn't the point here.

[fresh]

Originally Posted by mrhasan

Then why this line?

I presume he meant you will most likely upgrade to LEDs for the purposes of dropping temperature for example.

[sphelps]

Originally Posted by mrhasan

Then why this line?

I said probably which doesn't mean they won't save you money and that's just a personal opinion, far from fact. Quite simply put the potential is certainly there but whether most will be able to take advantage by sticking with the same fixture for long enough is debatable. Again the real point was additional heat isn't a huge factor and if it is it's something that can be minimized.

[fresh]

I am not planning an LED upgrade any time soon as I am happy with my HQI setup (upcoming summer temps might change that thought), but I truly enjoyed reading your findings and find them very informative.

As a matter of fact, I don't believe anyone else has done a similar mini-study, so THANK YOU for taking the time to perform, document and share with the rest of us.

[globaldesigns]

4.37 kWh per day X 0.0914240 (I just paid my bill, took the highest level for worst case scenario) = $0.40 per day

$0.40 X 30 days (just to average a month out) = $12 per month

$12 X 12 = $144 per year

So if I end up spending $$$$ for 3 Ecotech Radions G2 @ $660 each = $1980, this doesn't inlcuded taxes, figuring out how to put these over my tank using a bar system, etc.

So even if we just take the cost of the lights $2079 including GST... It would take 14.4 years to see the value. Now this isn't taking into the cost of new MH and T5's, but even if I religously replace them every 12 months, with a max cost of $200-300, I don't find LED's worth it. Especially when you hear about them burning out, fans quiting, new software, new lenses, new this and that.

Now in saying this, if you are new to the hobby and need to make an investment on a fixture, then maybe LED is a solution, but for us that have already made investments in what we already have, replacements are not worth it in my opinion.

Plus won't there be something better coming out soon?

[jorjef]

Oh I wish Dr. Molson was still available for times like this.. Why pay more for Honey Nut Cheerios when the regular ones serve the same purpose... why why why

[ocean diver]

I love my LED's I switched because I was sick of buying new T5 bulbs every year, so if all I save is the $200 a year (bulb replacement) then so be it.

[sphelps]

Honestly my numbers aren't there to justify how much money you'll save on your tank if you switch to LEDs, the numbers will vary greatly. If you're using them for this purpose then you missed the point completely.

[sphelps]

OK, I just noticed a huge flaw in my numbers. The 0.84 kWh per day for the mitras is only one fixture. See correction below:

Executive Summary:
LED power used: 2.52 kWh per day
Metal Halide Comparison: 6.12 kWh per day
Heater power saved from Halides: 0.91 kWh per day
LED power savings: 2.69 kWh per day
In this case the power saved with LEDs is still substantial including the extra power requirement from heaters.

Some system details
Display tank volume: 270 gallons
Connected frag tank and sump volume: 70 gallons
Realistic water volume approximation: 300 gallons.
Maintained water temperature: 78F
Lights: 3 x Mitra
Heaters: 2 x 300W

Insulation and equipment heat addition:
15mm glass with only view-able side but has an open top.
Sumps are acrylic and contained in a humidity controlled room which stays fairly humid and warm meaning heat loss from the sumps will be minor.
I'll installed all my pumps internal to take advantage of their heat loss.
I also have fridges under the main tank which vent around the sides and back.
In other words I've taken some steps to add as much heat to the tank from equipment and keep it in as much as possible without doing something that would have negative effects. I mention this because I think it's important when looking at your own tank you consider how heat loss/addition will effect your savings.

Measured Results:
Lights run for 12 hours, peak at 135W dimming up and down. Power used per fixture per day is 0.84 kWh, total for all three fixtures 2.52 kWh per day.
I measured the power used by the heaters a few different ways, during the full 12 hours on different days, during the peak light time and 24-7 to get a feel for any changes in usage that occur. I concluded the heaters duty cycle doesn't fluctuate substantially and they use an average of 0.13 kW per hour.

Now for the debatable part, the comparison.
The mitras run in high output mode, GHL claims it's comparable to 340W of halide, however I would no way compare the 12 hours of ramping up and down to that of a solid state 340W halide. Rather I believe it's comparable to 6 hours of equivalent halide which is 6.12 kWh per day excluding any inefficiencies.
In my experience when halides are on, heaters are off. I also think another hour is fair for a cooling off period. In other words I'm assuming the halides save me 7 hours of heat which is 0.91 kWh per day.

Conclusion
LEDs save me money in electricity even with heating cost included. A total savings of 2.69 kWh per day or approximately 44% decrease. However I believe the steps I've taken to with hold heat are a key player for this savings, I've noticed the heaters activate much less frequently from switching to acrylic sumps alone. I also maintain my temp at 78F while many SPS gurus will keep it closer to 80F which could play a role as well. This of course was also a winter reading, results will be different if house temperature climbs during hot summer days. Other peoples results will vary but the substantial difference I measured should conclude in virtually all cases the electricity savings are real.