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Measuring the electricity usage of water heaters

 
Posts: 554
Location: Asheville NC
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Ive been talking a big game for some time now about how Iam going to make drastic cuts to my electric water heater energy and environmental costs. Ive finally reached a milestone of measuring my typical usage without improvements over the past month.

Everybody uses energy a little differently, but its common for the water heater to be the second biggest energy user in most homes. In my single person home, the water heater is the biggest electricity user by far. I heat with fuel oil, and as little as I use, I tend to think that my water heater represents the biggest portion of my home's environmental impact. I take ridiculously long, hot showers. My showers are much more wasteful than most folks but I think the fact I do very little laundry tends to balance this usage out over average people. Iam not willing to sacrifice this lifestyle choice just yet.

To get an accurate measurement of the water heater's usage, I followed the advice of WaterHeaterTimer.org and installed a dedicated sub-meter. http://waterheatertimer.org/ I recommend anyone interested in this stuff to check out this website. Its a rich source of helpful information relating to electricity and water heaters.

I installed my 50 gallon Rheem marathon tank water heater about 5 years ago after my old one failed. It was the most efficient electric water heater available at the time but arguably its greatest feature is the plastic lined tank requires no anode rod maintenance, the thing that leads to the death of most electric tank water heaters. Ive heard that adding water heater insulation jackets to tank water heaters that are this efficient is a waste. I strongly disagree and am very happy I added a cheap fiberglass jacket to this heater at the time of install 5 years ago. You can feel the heat with your hand when you peel the top of the insulation back. I also have very short hot water supply runs which are fairly well insulated. There is certainly room for improvement as I want to insulate the expansion tank directly above the insulation. Its easy to feel the waste bleeding off in this area.

One month of metering revealed I used 205 KW. This is an insane amount of electricity. Its the rough equivalent to burning 2050 100 watt lightbulbs for an hour. Even if thats not a lot of money, its a helluva lot of pollution.

So now my question is how does this compare to the average american? According to this website (and waterheatertimer.org), Iam only using roughly half of the average amount. http://www.glendalewaterandpower.com/rates/appliance_operating_costs.aspx According to this calculator, I use more than average http://energy.gov/eere/femp/energy-cost-calculator-electric-and-gas-water-heaters-0 According to this fact sheet put out by Duke energy I use almost 3x as much as most folks. http://www.duke-energy.com/pdfs/Appliance_OpCost_List_Duke_v8.06.pdf

Not coincidentally, Duke is the company I buy power from and just had a devastating coal ash spill on the Dan river. http://www.latimes.com/nation/la-na-coal-ash-20140220,0,3738665.story#axzz2u50Bg4fg What is it with coal ash spills lately!!? This is the type of cost that is not included in monthly energy costs associated with electric water heaters and incandescent light bulbs. Sorry, rant over for now..

Well now that I have measured my actual normal usage, its time to do something about it and then measure my success of reducing this impact (with zero lifestyle change) or lack of success. Has anyone else directly measured the electricity usage of their water heaters? I still have no idea how I compare to most americans although I hope permies folks dont average more than me.
 
pollinator
Posts: 8304
Location: Victoria British Columbia-Canada
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Brian, I know that you regularly help others to reduce their environmental footprint. Hopefully you have built up some good karma. I'm an atheist but still believe there should be a special place in hell for those who heat with oil. A 50 gallon tank for one guy. I'm glad that you're doing something about this and look forward to seeing the results. A big, well insulated tank with short runs is better than some of what I've seen. One mobile home had a little 15 gallon RV tank in the unheated crawl space behind the skirting. This thin walled thing pissed heat to the outdoors 24/7.

----- Let's make it a contest. -----

You're aware of my electrical plans for the cottage, which will use about one cent worth electricity per day once occupied in a couple months. It may use seven cents worth once a well goes in and a big screen TV is added in the future. Let's make this a contest to see how efficient we can become. The only way this can work is if we each start with a base line. You start at your current usage before improvements and I'll start at 1 Kwh per day, which costs 7 cents in BC. After a year, we'll check to see who is using the smaller percentage of their base line. I already concede that your savings will exceed mine on a dollar value scale.

Do you accept this challenge ? The winner gets to post a photo or video of himself doing a victory dance.
 
Brian Knight
Posts: 554
Location: Asheville NC
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I hear you on the oil heat thing Dale. Unfortunately, my oil heat is a drop in the oil drum compared to the oil I burn for transportation and I live right in the city. Iam hoping there is a mini-split in my future which would hopefully break even or do better than the whole site vs source energy argument for heating costs both monetary and environmental.

As for your challenge, I accept but anyway we could keep it to water heating? I guess if you heat water with combustion it might be more math and assumptions than Iam willing to get into..


 
Brian Knight
Posts: 554
Location: Asheville NC
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So I have 8 months of pre-improvement recording and 1 month post improvement. From January 15 to October 15 2014, I used 1113 Kilowatt hours of electricity to heat my water. Ouch!

Before my October improvement I averaged 131KW per month. Here is how it breaks down per month:

Feb: 160 KWhrs
Mar: 151
April: 190
May: 164
June: 107
July: 74
August: 89
Sept: 113
Oct: 65

So the trend of using less in the summer months was expected, my showers are not nearly as long or hot during the warmer months. I didnt really think the summer would account for such a difference between the winter. Looking back on my first post, I must have gotten that 205 wrong because I originally wired the meter backwards and didnt account for the screwup in the right way.

On September 15, I installed my compost water heater and Iam pretty happy with that 65. It seems to have cut my water heater electricity usage in half if not more. I had no idea what to expect and wasnt even sure the improvement would be measurable. It would have been great to get a full year of measurements pre- compost but I just couldnt wait anymore.

Its obviously very early in the process and Iam not sure how long the heat will last before dropping off. I had been getting 100 degree water from the compost pile and a recent check showed it closer to 90 so it might be dropping off production sooner than I had hoped. Still, Iam pretty happy about the initial results. Of course I will be posting about the compost water heater in detail soon I hope.

If anyone plans on improving how they heat water I suggest getting some measurements going beforehand to better measure the results and maybe help others make informed decisions.

 
For my next feat, I will require a volunteer from the audience! Perhaps this tiny ad?
Hope in a World of Crisis - Water Cycle Restoration
https://permies.com/t/118080/Hope-World-Crisis-Water-Cycle
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