When to switch off an electric water heater?

[squarecube]

Hello. I'm new to the list, however I've lurked for some time as I have three fireplaces and one wood buring furnace at weekend house in Northwest Ct.

I was wondering when it is worth my bother switching off the electric water heater? If I'm away for 3 days, or one week or two weeks?

 

[kjklosek]

You would probably spend as much money bringing the water back up to temperature after 3 days than you would just letting it sit.

Instead, get one of those water heater insulation blankets. They really do work.

J.P.

 

[Eric Johnson]

For extended periods of nonuse, you might want to turn it down to its lowest setting.

 

[Eric Johnson]

Pook, you're an amazing source of obscure information. Thanks for that. 100 watts an hour seems like a pretty steep price to pay for maintaining hot water in a tank. Makes you think.

 

[Cazimere]

If you spend a lot of time away, you might want to consider an Instant Hot Water system.
There's no holding tank to store hot water. Could save you some bucks.

 

[Highbeam]

By 100 watts per hour do you mean that keeping tha tank full of hot water consumes electricity at the same rate as a 100 watt light bulb would? That is amazing. A 100 watter is pretty hot and bright.

 

[saichele]

But really, 100 watts an hr is 2400 watts a day, 2.4 kW, or about 24 cents a day for hot water on demand? About a third of what Sally Struthers wants. Even if you went to a tankless, that's $75/yr in savings. To replace a failed tank it's probably fine, but tough to justify in the meantime. Esp. since the $20 blanket will probably cut the annual cost in half.

Steve

 

[squarecube]

snip
Esp. since the $20 blanket will probably cut the annual cost in half.

Steve

Thanks for the tip. I have sort of forgotten 'bout these blankets. However, I have a more pressing problem right now. I bought this weekend house in November and have been turning the hot water off each Monday morning at 5am. I just discovered that the breakers labelled "hot water heater" don't really do anything. I played around with the other breakers and couldn't really determine which turns off the water heater. All the other breakers that are "tied together" (240 volts) seem to run other appliances (stoves, dryers, etc) but nothing shuts off the heater. Oh well.

 

[Highbeam]

Does your neighbor's porch light keep going on and off as you flip that breaker?

I replaced my electrical panel last year and marked one breaker as "mystery" and left it off until I found the outlet which it fed. It was the wash machine's 110 volt plug and we are using a stacked 220 volt unit fed by the 220 dryer outlet. Surely the water heater is powered by something?

 

[cbrodsky]

But really, 100 watts an hr is 2400 watts a day, 2.4 kW, or about 24 cents a day for hot water on demand? About a third of what Sally Struthers wants. Even if you went to a tankless, that's $75/yr in savings. To replace a failed tank it's probably fine, but tough to justify in the meantime. Esp. since the $20 blanket will probably cut the annual cost in half.

Steve

Someone beat me to it

I still don't get the tankless fad - people are spending thousands of dollars to save at most, $75/year in savings when a few bucks in insulation on a tank would go a long way. And this is a generous number because that "tankless" unit is still not 100% efficient in terms of delivering all energy to the user at the tap.

If we get to an intelligent utility grid, which is coming quickly, water heaters are a great way to use off-peak power to store up energy overnight cheaply, helping to balance the grid - a place where electric tankless can do a lot of damage. Electric cars/plug-in hybrids are probably an even bigger application on the horizon for using this off-peak power.

-Colin

 

[Cazimere]

Not necessarily thousands of dollars.
It depends on your individual application.

http://www.designerplumbing.com/store/Stiebel_Eltron_All.html

 

[cbrodsky]

Not necessarily thousands of dollars.
It depends on your individual application.

http://www.designerplumbing.com/store/Stiebel_Eltron_All.html

These are a disaster for the power grid unless you take showers at very odd hours... on top of that, you're still looking at non-zero standby losses from every single unit.

And to supply a house, you're looking at quite a few units - one for every shower for starters, so for a normal house, you're still getting into a couple thousand or more. The sizing charts make this clear.

-Colin