electric water heater shutoff with breaker

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  #1  
Old 07-17-11, 06:23 AM
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No but if you are going to do it very often you might want to install a switch at the heater or use a breaker rated for use as a switch. Why are you turning it off?
 
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Old 07-17-11, 10:13 AM
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Whats the standby heatloss for e WH set @ ~130*f in a 80* f room.....approximately
Impossible to calculate without knowing a whole lot more but most likely in the neighborhood of 1/2 to 2 degrees per hour. The lower figure would be a newer tank that has foamed insulation and a room that has minimal air currents. The higher figure for a tank with only fiberglass insulation and the room having a lot of air movement near the tank.
 
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Old 07-17-11, 10:48 AM
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Most newer breakers are switch rated. If it is just a short term project, I'm sure it will be fine.
My old house used an off peak water heating program where it only heated the water during off peak times. 11:00am - 1:00pm and over night. The water was cooler in the evening when I took my shower but still plenty hot. At that time they used 2 - 80 gal heaters. Now they use the Marathon 105 gal.
 
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Old 07-17-11, 10:54 AM
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More to the point....why do you want to turn it off? If it's just while he's at work or gone for a day...I don't see the point. More wear and tear on the breaker. The stat probably wouldn't even turn it on til it went down 10-15 degrees..and only for a few minutes at most.

Away for 3 days or more...sure.
 
  #5  
Old 07-17-11, 02:39 PM
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Wow...you must have outrageous electric rates. It would run me about $3 to maintain the WH with the numbers you listed.

I may be wrong and it will depend somewhat on the WH itself....but IIRC it will take just as much to heat a cold tank to operating temp as it will to maintain it at that temp....possibly more since all the components (shell, insulation, inner tank, etc) will also need to be warmed up again.

If this is only for short term (overnight, during the day, etc) on a regular schedule, you could just install a timer. Of course you'd be spending the money, but it would be more convenient.
 
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Old 07-17-11, 03:12 PM
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Ouch....that IS outrageous. Mine works out to about $.08 total.

I won't argue about the power thing with you...but it all depends on how long it is off, the age of the WH (insulation), and temp of incoming water. It takes a certain amount of power to heat a certain amount of water a certain amount...that's physics. Its not quite the same as a light bulb. On uses power..off doesn't.

I will agree that if you take 50 degree water..put it in a tank (WH) in the house and let it come up to ambient temp (say 70 degrees?)...then heat it...it will use less power than heating the initial 50 degree water from the ground.

All depends on usage...as I said.
 
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Old 07-17-11, 11:29 PM
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Vic - Under normal circumstances there is very little difference between leaving the heater on 24/7 vs turning it off. Any savings you realize by turning it off are lost when you turn it back on and the water has to be reheated.

However most POCO offer "Time of Day" metering as an option, where off-peak (8pm-8am M-F, and 8pm F - 8am M) power is much cheaper than on-peak. If you have this type of billing and use a timer to turn the heater off during peak billing, then only the cheaper 'off-peak' power is used to heat the water resulting in significant savings. In most households this is viable, since most showers are taken before 8am, and a well insulated tank does not lose an incredible amount of heat in 12 hours, even if a moderate amount of the hot water is used (hand washing, etc).

I had this in my first apartment. The on peak was $0.24/kWh, while off peak was $0.11. I only had a 20 gallon heater, but I lived alone, and I never ran out of hot water during the day. The cost of the timer was recovered in less than 6 months in what it saved me on electricity.
 
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Old 07-18-11, 06:09 AM
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I FIGURED THIS MATH , WITH [email protected] $.17/KWhr I can simply divide by 8 to calculate cost. So my 40w bulb running 24/7 will cost me 40/8= $5 your rate would be divisible by ~16. So 40/16=$2.5
40 watts times 24 hours is 960 watts. 1 KWhr is 1000 so running a 40 watt bulb all day would cost you about .17 cents a day.

My son's project.
Whats the standby heatloss for e WH set @ ~130*f in a 80* f room.....approximately
Remember he is doing a project here. I think he can safely turn the heater on and off with the breaker until his project is complete.

Mike NJ
 
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