Estimating/Measuring Hot Water Heater Electrical Usage?

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I have a traditional 220 volt electric hot water heater and would like to estimate or measure how much electricity it is using.
Suggestions?
Has anyone here done this? What results did you find?
Are there any national statistics on this?
Thanks.
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Jonathan Grobe Books
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Jonathan Grobe wrote:

Or you could time the electric meter going around. Hook a 220V clock across the heating element. The clock runs only when the heater is on. Have an electrician do it. House wiring is unsafe....my lawyer made me say that... 'cause it's true.
Depending on the age of the water heater, there's an "energy guide" sticker on it that shows the range of usage for that type of appliance. If not, go visit a water heater store and read some labels there.
All electric water heaters use the same amount of energy to heat the same amount of water. Differences are in how much energy is lost thru less-than-perfect insulation.
I just went thru that procedure using a current clamp and a computer. I can tell you exactly how much my water heater is costing me. A shower costs me 16.5 cents. But...I only have one option. USE LESS HOT WATER. And I don't need ANY measurements to tell me that.
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-snip-
And the temp differential in the room, and usage. . .

I think that's what the OP is asking. Tell us more about your current clamp & computer setup.
Jim
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Jim Elbrecht wrote:

1mv/amp. Maybe usable for a water heater, but I wanted something more sensitive. The Triplet model 10 current clamp is designed to hook onto a 50 year old analog meter. It puts out 3VAC full scale from as little as 6amps. And it doesn't need a battery. Plug that into a Radio Shack DVM with RS-232 output. Then it's just a matter of a simple visual basic program to read the meter and log/graph/analyze the data.
It worked, so I intended to build a second generation using a pic processor and bluetooth transceiver and do the acquisition and analysis on a PDA. But then I realized that the data wasn't much use anyway. What I needed was to use less hot water. Didn't need any data for that conclusion.
I did need a way to measure consumption from things that I couldn't easily get at. Air conditioner is the most obvious. Power factor is an issue. So, I sidestepped the whole issue and went straight to the source. The power company meter on the wall puts out an infrared pulse for every watt-hour consumed.
Turns out that the older PalmIII PDA's PALMOS 3.5 will let you trick them into reading that pulse thru their IR port. And there's a trialware basic interpreter available for free. It has limitations, but works great for this.
So, go to Walmart and buy a yummy single slice of cake. It comes in a plastic container that's a press fit over the power meter. Stick in the PDA, press it onto the meter and log yourself silly. You're gonna have to use bigger batteries in/on the pda to get sufficient run time.
With a little experience, it's easy to distinguish the signature of the water heater, air conditioner, microwave, stove etc.
NO power factor issues or accuracy issues. You're measuring EXACTLY what the power company is billing you for.
For about $25 on ebay, you can buy a "blue line innovations" wireless remote reading power monitor that will also work with the old-style power meters with the wheel that goes round and round. They work well, but only accumulate total consumption.
I also wanted to monitor the air conditioner without a lot of post-processing of data. The same pda and almost the same program can be used with a wind-vane/microswitch into the serial port to sense when the fan is running. That's pretty close to the on-time of the compressor. Also works with a gas heater. That did supply some useful information that led to shading the front of the house on hot afternoons and reducing electricity consumption by about a third. My front door is no longer 185 degrees.
While I've got your attention, I'm interested in ideas on how to reduce the attic temperature from 136 degrees. I tried blowing air up into the attic with a 15" fan, but it hardly put a dent in the temperature. The math suggests that the insolation is pushing over 100KW into the attic. A fan to push out that much heat costs more to run than the improvement in air conditioner efficiency saves...according to the back of this here envelope. Ideas?
mike
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How about 2 identical 110v clocks in series...or a neutral and one of the 220 wires to the elements? ...and remember you don't NEED to heat HOT water! (someone had to say it)
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Bob Villa wrote:

I don't think my water heater has a neutral wire??? running it to ground would work, unless you have GFI or let an inspector anywhere near it.
Safer would be a resistor or a transformer off the 240V.

Speak for yourself!!! I NEED hot water.
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You don't NEED hot water...if it's HOT!
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wrote:

Turn it off for a day..
If you have low flow shower heads, you should be able to coast thru the day on one tank..
At day break the next morning.. Read your electric meter to 10th's of kwh and the turn the HW back on.. The meter should spin like a top until it reaches temp (less than a hour).. Re-read the electric meter..
Then add in 2 or 3 kwh to that figure compensate for not maintaining a constant temp during the day. (Warmer tanks loose more thermal energy to their surroundings)..
Variations of this method can be used to measure HW energy usage to dish washer and washing machine.

Just keeping a wrapped HW @ temp with no usage consumes 2 to 3kwh per day..
I now turn on HW for just a few minutes to warm up enough water for the task at hand... shower.. 8-14 minutes(depending on season) .. Dish Washer (15 minutes).. Laundry. 25 minutes for 4 to 5 warm(wash)/cold(rinse) loads for my front loader washing machine.
note: This technique significantly extends the life span of the HW..

It's going to vary based on local climate and incoming water temp, etc..
P.S. I live in a hot climate..

http://www.aceee.org/consumerguide/waterheating.htm http://www1.eere.energy.gov/consumer/tips/water_heating.html
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Shut it off for a day or as many as you can and monitor the meter, where I am and for most of the country electricity is more than double the cost of Ng
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On Fri, 16 Jul 2010 03:44:12 -0700, ransley wrote:

Here on the west coast we pay only 6cent/kwh vs triple that on the east so NG and Electric are approx the same price per btu. The OP would be much further ahead upgrading his building envelope to KEEP the HEAT in or COLD if he lives in a warm climate. I reduced my heating costs from $1200 to $300 per year with new furnace, windows, air sealing, insulation etc. He may also want to consider localized mini HW heaters near the kitchen and main bathroom
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On Sat, 17 Jul 2010 10:56:09 -0700, Smitty Two

Seems like the highest rate in California approaches a quarter. [Fresno, if I remember right]
Had to check-- Fresno is right http://www.greenfresno.org/profiles/blogs/pgampes-outrageous-electricity
1000kwh cost $241-- the top rate is $0.4739 after 1070kwh.
Good thing nobody needs A/C in CA.
Jim
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On Sat, 17 Jul 2010 12:38:04 -0700, Smitty Two

I was joking- I spent the winter in San Diego in 69. And the month of May at Camp Pendleton. Was damn glad to get out of California before summer. [of course I went to a warmer climate yet-- but that's beside the point.<g>]
Jim
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Astounding. Has anyone lampooned the OP for wanting to heat hot water? I don't remember seeing it yet, in this thread.
--
Christopher A. Young
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On Jul 20, 8:16pm, "Stormin Mormon"

You haven't looked nearly hard enough!
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On Wed, 21 Jul 2010 09:16:34 -0700, Smitty Two

Or he was just ignoring the pedants who think they are so clever. I don't stop heating my water when it gets hot. I heat it another 10 degrees or so. A friend heats his 30-40 degrees past hot.
Jim
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electric usage is largely dependent on hot water usage... standby losses of newer tanks is very low, and yours should have a brite yellow energy label on it.... detailing normal consumption...
beyond that why do you want to know?
someone trying to sell you a tankless? you believe your tank is running up your electric bill?
what other electric power hungry appliances do you have? electric dryer? electric stove? AC, espically window units///
I had a neighbor once tear out his seldom used electric pole light, and replace it with a gas one in a attempt to cut his electric bill.
I tried to tell him the problem was his electric dryer that ran constantly he was carrying for his elderly mom.stem emnated constantly from the dryer vent...
no he believed it was his pole light that was hardely ever on. and refused to believe a gas dryer would cost less to operate than electric.....
so whats up with you?
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In future years I expect massive energy costs increases as well as a substantial decline in my income. So I want to cut energy use substantially. Right now I am trying to find out exactly how much energy each appliance, etc is using. If I know how much it is using I can evaluate alternatives.
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Then junk the electric and go gas if you can for everything. If you really want a better idea compare everything by BTUs and cost, you can figure a conversion cost of BTUs for electric and gas, I am maybe 60% more per BTU for electric and electricity will always be more than gas, Now in this heat alot of my electric come from Ng powered substations.
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I don't have natural gas available; only propane--which is substantially higher price than natural gas. And if I get propane part of the energy is going up the chimney. So it's not that clearcut like it is for natural gas.
But I have been thinking of propane tankless, solar powered and electric heat pump as alternatives. But they all depend on exactly how much money they would save vs how much they would cost.
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Jonathan Grobe Books
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Huh? It's easy to compare natural gas and propane prices. The appliances are the same with (usually) just a orifice change. The energy usage is the same.

It won't be cheaper to convert today.
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