Water heater on a timer?

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Hi ladies and gents. I've recently been talking to my dad and a few others about the benefits of turning the Electric water heater off except certain times of the day when needed and began to really wonder if this can save much on the electric bill?

Yes I know it constantly runs to maintain the water temp but wouldn't it be counter-productive to leave it off all day while at work and then turn it on late in the evening when everyone needs a shower? To me, that would require the elements to stay on 100% DC to heat the entire 55 gallons back up and cause a higher use of electricity vs just maintaining the temp by cycling on and off throughout the day.

I've see the "Little grey box" and other timers as well as folks just wiring in a switch. Is there some validity to this or a waste of time and money? What say you?
 
Think about it like this... There is constant heat loss from the system, whether it's powered on all day or not. The energy will continue to try and equalize to the outside of the tank. The hotter the tank is, the more energy there is present to escape.

So if you cut the power and allow the energy to escape without replacing it all day, then turn on in the evening and bring the water back to hot, you will lose less energy to waste.

There are a lot of variables here that will change your result. Is the heater in a cold or warm environment? How well is the tank itself insulated? Is your electric rate fixed all day, or are you subject to peak and off-peak rates?
 
Had a little Gray Box on my water heater three houses ago. On a 50 gallon tank. It powered off at 9:30 PM back on at 4:30 AM then back off at 10 AM and back on at 2:30PM it did save me several dollars a month on my bill. Power is more expensive now and these timers are now more programable than mine was. Now some of the boxes allow you to program different hours each day and weekend plus vacation shutdowns.

Oh my Little Gray Box had a cavoite don't use with aluminum wiring.
 
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Back in the days I had an electric water heater at home, that you need to manually turned on 30 mins before taking a shower. So yes it can be done, but you won't know how much electricity you will save until you actually try it out.
 
Personally I'd want to hook a temp sensor and wattmeter and measure. So as to be sure.

My thinking: let's say I turn it off, it's off for 8 hours, and when I turn it back on, the water is still at say 100F. I probably am not saving much energy--my thinking, somehow I wind up using the same amount of energy over the course of a day. I realize the bigger the temperature difference from inside to outside -> faster heat transfer, but I'm thinking, a low duty cycle over a long time could be the same effect as high duty cycle but only some of the time.

Now if the tank was hitting ambient long before I switch it back on, then I'm guessing I'd have savings.

Then again, you lose nothing by trying (only time spent waiting for the tank to come up to temp). Proof is in the pudding: does it save energy & money for you?
 
The better insulated a water heater is the less you will save. Feel the outside of the water heater? Is it warm to touch or room temp. I don't think you will save much with a well insulated water heater.

If the heat from the jacket of the water heater goes to heat a lived in room, then its less your furnace will be on. Furnace may be gas and water heater electric.

At one point in time they had off-peak power switch for the electric water heater. Power company controlled when the water heater was on and when off. You got a cheaper rate allowing them to control water heater.
 
As a preparation for the future, I installed a tankless (gas) water heater and solar panels.
I guess I would try and insulate the water heater as best as you can.
Good luck.
 
I once turned off the water heater for a weekend. Upon return I took a shower, and didn't realize I turned off the water heater until I finished my shower. That's how efficiently they hold heat.
 
If you have off-peak metering go for it. Otherwise, don't. Tepid water is a great way to get Legionairre's Disease.
 
I had 1 of those grey box timers, saved a few dollars, what has saved me a lot was switching to heat pump water heater, it cut my electrical bill in half.
 
Originally Posted by eljefino
If you have off-peak metering go for it. Otherwise, don't. Tepid water is a great way to get Legionairre's Disease.


+1
 
The best thing you can do is to compare KWH cost with nat. gas cost if available. In OH the cost of nat. gas to heat water makes electric water heaters obsolete. FWIW.


Oldtommy
 
Originally Posted by 2oldtommy
The best thing you can do is to compare KWH cost with nat. gas cost if available. In OH the cost of nat. gas to heat water makes electric water heaters obsolete. FWIW.


Oldtommy



This is very true even with my heat pump water heater in eco mode its 2-3x the cost vs natural gas.

conventional electric is around 8-10x the cost to heat vs natural gas (NE OHIO prices)

Disclaimer:IIRC its been a few years since I ran the numbers..
 
Originally Posted by Rand
Originally Posted by 2oldtommy
The best thing you can do is to compare KWH cost with nat. gas cost if available. In OH the cost of nat. gas to heat water makes electric water heaters obsolete. FWIW.


Oldtommy



This is very true even with my heat pump water heater in eco mode its 2-3x the cost vs natural gas.

conventional electric is around 8-10x the cost to heat vs natural gas (NE OHIO prices)

Disclaimer:IIRC its been a few years since I ran the numbers..


Heat pumps also dehumidify.
 
Thanks for all the input!

I'm currently trying it now via manual tripping of the breaker at night before we go to bed (10pm) and then we turn it back on later that afternoon when my wife gets home from work (3-4pm) So far it has not caused issues with the family showers usually beginning about 7-8pm every night,

We live in central Florida and the WH is enclosed in a small area in the laundry room, it is very well insulated from what I can tell and only about 5-6 years old.

FWIW- we do not have natural gas as an option out here so that is a no-go. We also do not have peak/off peak pricing on our electric. It is a steady $.11-13/KWH here.

My unit is a dual element type with I believe (2) 3500W elements. I have the thermostat set to 120* F.
 
I think you'd be surprised at how little heat it loses once up to temperature. I wouldn't bother with a timer.
 
I went through a stint of flipping it off at the breaker every day after I'd taken a shower, and then not turning it back on until ~1 hour before(I usually take a shower at night, but if I knew I was going to be taking one in the morning I'd turn it on right before bed).

I saw maybe $1-2 difference per month over the course of a few months. Ultimately I quit, though, when I realized the temperature hadn't dropped all that much(about 15ºF with the hot tap turned on all the way) even after being off for a weekend when I was away.

I suspect that you'd save more money by shortening your shower time a minute or two and/or dropping the temperature of your shower a bit. Ultimately, the biggest energy drain is from having to heat water coming in to the tank, not from keeping stored water hot, and using less hot water will help you out on that.
 
Never thought about it. We just replaced a 28 year old 30 gallon natural gas unit with a new 40 gallon Rheem gas unit. Both are very inexpensive to operate. I think we spend $10-$15 per month.
 
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