LEDs and electricity savings

[sphelps]

Oh no another LED thread to discuss electricity savings

Actually I just wanted to share some results I recently measured. Not long ago I wondered how much power I was actually saving with LEDs compared to a lighting source such as metal halides. One of primary reasons many of us make the switch is the potential for such savings, among others, but some of us have often wondered if the savings are that substantial when you consider your heater may have to work a little harder to combat those "cooler" LEDs. So I decided to measure the power consumption of each and see exactly what I'm saving. I'm sharing the results more for "food for thought" purposes, everyone will get different results and may make different assumptions than me.

Executive Summary:

• LED power used: 0.84 kWh per day
• Metal Halide Comparison: 6.12 kWh per day
• Heater power saved from Halides: 0.91 kWh per day
• LED power savings: 4.37 kWh per day
• In this case the power saved with LEDs is 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 day is 0.84 kWh
• 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 4.37 kWh per day or approximately 70% 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.

[mrhasan]

Hahaha. I knew you opened this thread as soon as I saw the title :P

We are talking about $10-$12 savings over here right?

BTW I am still wondering one thing; why do reefers have such spikes in electricity bill? Like without something like 300gallons+, you will be pretty much within the $100 range (at max) for running a big tank isinit?

[sphelps]

Could be people using a variable electricity rate, which I had last year and it changed from $0.06 to $0.14 throughout the year. Otherwise could be those using chillers at certain times of the year or a number of other reasons relating to equipment changes and tank demands but nothing that shouldn't be fairly obvious to the user.

Yes savings for me works out to around $10-$13 per month.

[ocean diver]

So let say $120-$156 savings per year plus the costs of Bulbs you would replace. Depending on how many T5's you have plus halides.

[sphelps]

Originally Posted by ocean diver

So let say $120-$156 savings per year plus the costs of Bulbs you would replace. Depending on how many T5's you have plus halides.

Yeah probably roughly $150 per year in power savings. If I only ran 3 halides which I somehow managed to run at 340W for 6 hours per day I'd probably only change the bulbs once a year so it depends what you pay for bulbs but I say around $400 per year. Given the cost of the fixtures it's around 8 years pay back. Given the total cost of my LED adventure the pay back period would be substantially longer So LEDs haven't and won't actually save me money.

[mrhasan]

Originally Posted by sphelps

Yeah probably roughly $150 per year in power savings. If I only ran 3 halides which I somehow managed to run at 340W for 6 hours per day I'd probably only change the bulbs once a year so it depends what you pay for bulbs but I say around $400 per year. Given the cost of the fixtures it's around 8 years pay back. Given the total cost of my LED adventure the pay back period would be substantially longer So LEDs haven't and won't actually save me money.

Something that I proved in a thread few weeks back

Hint: Just don't tell the dominating factor (eg. wife, girlfriend, not-reef safe person) how much you spent upfront for getting the LEDs and they will be happy with the upfront electricity bill savings

[ocean diver]

LOL that is because you bought Lights (3 x Mitra) that are in my opinion way over priced, but hey each to there own.

[kien]

Originally Posted by sphelps

Oh no another LED thread to discuss electricity savings

Actually I just wanted to share some results I recently measured. Not long ago I wondered how much power I was actually saving with LEDs compared to a lighting source such as metal halides. One of primary reasons many of us make the switch is the potential for such savings, among others, but some of us have often wondered if the savings are that substantial when you consider your heater may have to work a little harder to combat those "cooler" LEDs. So I decided to measure the power consumption of each and see exactly what I'm saving. I'm sharing the results more for "food for thought" purposes, everyone will get different results and may make different assumptions than me.

Executive Summary:

• LED power used: 0.84 kWh per day
• Metal Halide Comparison: 6.12 kWh per day
• Heater power saved from Halides: 0.91 kWh per day
• LED power savings: 4.37 kWh per day
• In this case the power saved with LEDs is 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 day is 0.84 kWh
• 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 4.37 kWh per day or approximately 70% 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.

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

[mrhasan]

Originally Posted by kien

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

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

[sphelps]

The point wasn't to compare fixture cost at all, only that LEDs can use substantially less power even with the added heater duty cycle considered. Something a few people have asked me.

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.