5500 watt elec hot water heater - 5000 watt generator

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Hello all,
I'm looking at replacing my current 80 gallon electric water heater. The current heater says the upper and lower elements are both around 3300 watts.
Most 80 gallon units I have seen in stores nowadays are 5500 watt units (upper and lower element are both 5500 watt).
I currently have a 5000 watt gasoline powered generator. Our house is wired with a transfer switch, and the current water heater is already wired into the transfer switch. We have crappy electric service, which is why I bought the generator a couple of years ago. We have had outtages lasting 1-2 days. In my area we had an ice storm a couple years back- remarkably, our crumby power stayed on, while most others were out for between 1-2 weeks. My point? We have outtages that last more than 3 or 4 hours, so there is a good chance we would need to heat water using my generator. I have used the generator to heat our water between showers when we were down for a day or so.
At my list visit to Lowes, I talked to a guy working there and explained my generator situation to him. He recommended that I buy the 80 gal electric unit I was looking at and just buy some lower watt heating elements to replace the higher watt ones that come with the unit from the factory. He said he had done the same thing at his house with no problem. Are there any problems that he or I don't know about by doing this? (other than it will take a little longer to convert incoming cold water to hot).
He claimed that by using the lower watt element it takes less energy to heat the water - he compared it to cars you can buy with two different size engines- one uses more gas than the others. I don't buy that. I didn't argue with him there at the store, but I believe it takes the same amount of energy to heat the water, just a longer time to use the same amount of energy to heat the same quantity of water.
The other thing I thought about doing was keeping the 5500 watt elements in it as is, and buying some extra lower watt elements for emergencies where we would need to heat water using the generator. I have never had to replace an element before- if you need to swap out both the top and bottom elements, do you have to drain the whole water heater, or can you do a fast swap, plugging the hole with a towel, etc. while you quickly switch each of them out? The heater is down in our unfinished basement, so if a little water got on the floor, it wouldn't be the end of the world.
Thanks in advance for your advice!
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why not disconnect the upper element when you're using the generator.
You could even wire in a switch to shut off externally.
Bill

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If natural gas (or LP) is available, I'd be looking at that as the first option...
--
Regards,
Doug Miller (alphageek at milmac dot com)
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Doug Miller wrote:

The most cost effective, over the life of the unit, water heaters available are the high efficiency oil fire units. The initial cost is high but they will save you money over the life of the unit.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
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spam disintegrator wrote:

Couple things: 1. Electric water heaters have never been known for their recovery rate, at least not in a good way. 2. They are very expensive to operate, unless you have unusually low electric rates, because of limited efficiency of generating plant. 3. In all that I've seen, the elements are _not_ powered in parallel; either to top one is on until upper section is heated, or the lower one is on as needed. Derating them should not be an issue; just a little bit tedious to do it right removing and replacing.
Suggestions: Solar, gas/propane, derated elements in electric, with use of cogen. The latter meaning: recover some of the 75-80% input loss (exhaust, engine cooling) of your generator into heating water.
J la
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spam disintegrator wrote:

For what do you need hot water?
Is this need so compelling that you can't heat what you need on a hot plate for a couple of days?
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bathing
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spam disintegrator wrote:

Personally I would use a hot plate. Can't you get by a few days without a hot shower? Trying to heat water with a generator is likely going to put a lot of wear on the generator. Those are going to be real expensive baths.
--
Joseph Meehan

Dia \'s Muire duit
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spam disintegrator wrote:

Oh. Well, you could go French.
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yeah, i agree with another poster- either the top or the bottom element is on, not both at once. And, each is 5500 watt when either is on.
also, we live in a semi-rural area- there is no natural gas line past our house. LP is not a near term option for us- we would have to bury gas line and the way our property is, i don't see a good spot for a tank where the delivery truck could reach his line to from our driveway. I know and agree with others that LP or nat gas is the most energy effecient. Trust me, if we were set up already for gas, we would have a gas dryer, hot water heater, range etc.
i also have a 2nd part to my question- Sears has a 12 year water heater on their web site. If you want to see what i'm talking about, go to sears.com and paste the item number into the search box. Then click the product specs tab. I'm looking at the Kenmore Power Miser 12- sears item # 04232184000, in the product specs it lists an alternate dual power option.
here is what it says: "Alternate Dual Power- Max Fuse Req'd- 20 amps; Minimum wire size - 12 ga; Wattage at 240V - 3800 watts"
yet, at the bottom of the page, it says: "Power - Type - Electric; Wattage at 240V - 5500 watts; Max Fuse Req'd 30 amps; Min wire size 10 ga"
When I called Sears cust service, I didn't get a warm fuzzy feeling that the woman on the other end knew what she was talking about. She said there is a bar that comes with the heater and that you put the bar somewhere to make the electric work different (3800 watts vs 5500). If this is true, it would possibly be an easy switch to run off of my generator. What I'm wondering is if the lower watt option is possibly for use in mobile homes, where the wiring is less beefy and different quality than in regular homes. Again, I didn't hang up the phone with a lot of confidence that she knew what she was talking about.
Thanks again!
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spam disintegrator wrote:

There is no problem swapping out the elements to lower power. Recovery will be slower, but that is the only downside. I have a 3700 watt Sears 35 gallon unit, and my 4400 watt generator runs it fine. I heat a tank of water, turn the tank off and start the well pump. My wife had the flu during our last outage, and being able to take a hot shower did a lot to make her feel more comfortable. With 2 gpm shower heads, a 35 gallon tank translates to a really long shower.
Swapping elements is not something you want to do in the middle of a power outage. Yes, you have to drain the whole tank.
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spam disintegrator wrote:

If you have a 20A, 240V outlet close to the water heater, then your wiring should be OK. You can see some pictures of various types of outlets at:
http://www.levitonproducts.com/catalog/dept_id_963.htm
In poking around Google, it looks like this water heater is made by State Industries a subsidiary of A.O. Smith. So, you might want to give them a call and ask them how easy it is to switch back and forth between the two wattages. Or, you might be able to go to the sears store and if they have one in stock, you could ask to see the manual. My bet is that it would be relatively easy to switch back and forth.
State Water Heaters 500 Tennessee Waltz Pkwy Ashland City, TN 37015 phone: 800-365-8170
A. O. Smith Water Products Company 500 Tennessee Waltz Parkway Ashland City , Tennessee, USA 37015 1-800-527-1953 FAX: 1-615-792-2163 snipped-for-privacy@hotwater.com
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do it. The only loss is through the insulation, and the insulation doesn't care what the elements are.
Consider running the heater on 120v during outages. It will only product 1375w, so your recovery time will be terrible, but it will work and doesn't cost anything. It would be better if you could get both elements to run at the same time, but I don't think that are designed that way.
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Which probably makes about 20 kW of "waste heat" :-)
Nick
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I suggest you TRY your generator on the tank. Its very possible it might run ok, although it will; be full load...........
Most enerators understate capacity and it may heat a bit slower while still heating acceptably.I aSKED A FRIEND WHOS OLD HOME RAN ON GENERATOR DURIUNG EMERGENCIES he had no choice being on A WELL
His 5KW generator tolerated his 5500 watt tank ok, although heating was a bit slower
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I don't know about that. That might be "pushing the envelop" a little too much.
We got the generator to run a sump pump when the power goes off. That is the primary use if the pump needs to run a lot. If the pump isn't running hard, we can turn it off and run the water heater, well pump, etc.
I'd hate to fry our generator and then have to buy a new one or end up with a few inches of water in our basement.
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spam disintegrator wrote:

I take it a gas fired water heater is not an option? I'm not sure I'd run a generator just to heat hot water. With power out and a tank of hot water, it's going to last a day or so if you use it sparingly. But if you want to use lower wattage elements, that is certainly an option. And you;re right, the bozo at HD doesn't know what he's talking about. It's going to take the same amount of energy with the lower wattage elements to heat the water, just over a longer time.
Even at 3500 watts or so, it still going to be sucking up most of the generator capacity for a long period of time. And I sure wouldn't try running a 5KW generator on a 5500KW water heater, as it will already be overloaded and then what about the rest of the house load for the next bunch of hours while it;s heating? Don't know about you, but I'd rather have the furnace, frig and lights going instead of the WH. You can just heat a pan of water occasionally as needed. People lived without showers for 1000's of years.
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yeah, gas fired water heater not an option. i'm not above going without a shower for a day or two- on the weekend. However, I wear a shirt and tie during the week. If it's summer time, I sure don't want to show up for work smelling ripe. And yes, we have a propane camp stove to heat water and cook with in an emergency in the summer time, as well as a wood burner and fireplace if it's winter time.
I would just like to have the hot water tank available if we would be down for a week etc.
anyone heard of the dual power option I mentioned a few posts back from Sears? Is this typical with any water heater you buy or just Sears?
I called and talked to another person at Sears. She tells me that the upper element is 3800 watts and the lower is 5500 watt. There is a "bus bar" that you can convert the lower element to only run at 3800 watts. Of course she promised she would email me a copy of the owner's manual- 12 hours ago (no email, big surprise).
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spam disintegrator wrote:

Did you look at Sears support online? Many times the manuals and documentation are there to download.
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Then again, you generator makes about 20 kW of "waste heat" :-)
Nick
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