High Tide Aquatics

anyone have an energy calculation spreadsheet

houser

houser

Past President
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I was starting to make an excel spreadsheet here to get a rough idea of complete cost of electrical consumption for my tank on an item by item basis so I could gauge the effects of making changes in hardware. For example, a switch from 250W to 175W MH. Then I thought anybody already have one?

BTW the savings (of course ONLY $$) in making the downgrade in my case was quite small. I was actually surprised to look at the numbers.

I have a kill-a-watt but am too scared to use it. But I bet feeding the info from the kill-a-watt into the spreadsheet would be good.

So if nobody has one, then I suppose in the near future perhaps we can use mine as a starting point.
 
I think the Kill-a-watt is good to tell you how much real energy any particular fixture is using, i.e. your 175W fixture is most likely using more than 175W. Also its awesome for heaters so you know how much time it's really been on or off in any given 24 hour period (use the kWh setting, last button?)

That said, use the KAW meter to find the real power of everything, record it down, record the time everything is on (except heaters you can simply enter the usage), pop it into excel and work the magic

Example of one of my tanks I whipped up in all of 5 minutes.
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Now figuring how much this translates to cost however is a little more difficult because of PG&E's tiered structures, the more you use the more you pay for that usage. If you don't use anything big that's seasonal specific (i.e. electric space heaters, air conditioning, hot tubs, pools) it's fairly easy just subtract your kWh per day x 30 from your last PG&E bill to see what everything else in your house uses. Even then it's not that easy because there are different "baselines" (what you're "allowed" to use before they jack rates up) based upon if its summer or winter, hell here in San Francisco we get screwed in the Summer, something like 8.3 kWh per day (and if you noticed I didn't even put my heaters in the above spreadsheet).

So overall it's not really that hard, however using that KAW meter definitely would be a good first step to find out true usage. However if this isn't enough to get you going, let me know, popping out spread sheets is always some really dorky fun I always liked doing :D
 
Spreadsheets are ok in my book too. And yea, I did note that your biggest energy hogs I bet aren't listed.

Got something similar, was creating separate calculations for components so I could play with 7hrs of light at 250W vs. 8hrs, against 175W, just to see what happens. Enter a rate and go from there. So far it was enlightening to see the numbers.

I'm going to play with it a little, then crack out the Kill-a-watt to close the loop.

So far all I did today was convince myself I don't need to downgrade to 175W since it really doesn't make a big impact $$. Funny I just assumed it would make more of a difference until I did the math.
 
Well assuming nice electronic ballasts that are 100% efficient (big assumption that's wrong), .25kW * 7 hours = 1.75kWh per day, .175kW * 8hours = 1.4kWh per day

So each lamp would change 0.35kWh per day, which depending upon which level you're at as far as electrical rates, would translate to about 15 cents per day if you were in the 45 cents per kWh tier. HUGE pay back times for a change like that.
 
Yeah, in Bryan's thread (the one "who spells his name correctly" :D) I think we convinced him out of downgrading from 400w to 250w for that reason.
 
Tumbleweed said:
sfsuphysics said:
Yeah, in Bryan's thread (the one "who spells his name correctly" :D) I think we convinced him out of downgrading from 400w to 250w for that reason.
Click to expand...

That what he thinks.
Click to expand...

:lol:

Next up, Erin or Aaron :p
 
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