Howdy all, can anyone tell me if a 50 gallon electric water heater that consumes 17 amps of electricity while on is normal?

In trying to figure out why my electric bill is HIGHER after getting a new ac installed, the tech measured the readings of the air handler and it was one or 2 amps, the compressor was about the same, but the water heater seemed really high to me.

Perhaps it's getting old and needs to be replaced. It's about 10 years old, I have no idea how long they are supposed to last.

I have been thinking about getting a tankless water heater for awhile, to save space, this may be the time.

But don't those things suck up electricity?

Any answers appreciated as always.

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Enough about me, how are you doing?

I don't really run into the electric water heaters much, but my friend had a problem with his recently. I guess his had two elements, and one burned out. So the 50 gallon heater wasn't quite heating 50 gallons of water, plus it was sucking a fair amount of juice since the one good element was trying to compensate.

I like the Rinnai's, I'm putting them in the houses I'm building. They cost us about $800 which is similer to a gas 50 gallon heater. Installation costs are the same, for us at least on new houses. On an old house it could be more because the on demand gas heaters use a TON of gas while they are on. Usualy you need to upgrade your gas line to 3/4 and put a higher flowing meeter on. But overall you do save money.

You also get a nice tax credit with some of the on demand heaters.

http://www.rinnai.us/tankless-water-heaters/

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17 amps is not high. Why would you suspect the water heater when you just had a new A/C installed?

The units are typically 3500W for a lower priced heater and 4500W for the better and larger units.

The equates to 14.6A and 18.8A using the typical 240V circuit.

I'm slowly coming to the conclusion that the standby losses in those devices are significantly higher than anticipated. One of the rental houses has increased the electric consumption by nearly 500kwh per month after installation of said device. This puts its cost significantly higher than the tankless coil in the boiler that it replaced.

I've got an electric water heater and total electric usage for my house is about 500 kwh a month. Your renters are just enjoying the endless hot water that new heater provides.

The renters are paying for the privilege to the tune of $100. per month.

The reduction in the use of oil due to the bypass of the tankless coil has amounted to negligible.

I conclude that the cost to actually heat the water with oil is a small fraction of the cost to heat and store 40 gallons of hot water with electric at $.20 per kwh.

I'm going to be forced to get the tankless coil cleaned with acid or replaced. The electric cost is ridiculous.

What about the installation of an insulated jacket around the body of the heater. Are they worth it?

Your cost for electricity is usurous. I pay $.16/kwh here.
I should modify my description of my household water heating. I run the water through the domestic water heating coil in the oil fired heating furnace and then into an electric 40 gallon heater. There are tables to compare oil/gas/electric per 1 million BTUs- oil beats the others by a wide margin, even $3-$4/gallon.

Well, we've got to pay for a $6B nuclear power plant.........that's never generated any power whatsoever.

I do the same thing........but the coil is in bad shape right now........the original reason to install the electric heater...........and the heating capability of the furnace is negligible.

When the coil is new, the water is sufficient if the boiler is kept above 180°.

I tried using only the furnace to heat water but there was too much variation in the temperture. And the furnace coil had only 1/2" fittings, whereas the electric heater has 3/4". The water from the furnace is mixed with cold as it enters the electric heater to temper it and increase flow. I can shower while doing laundry or running the dishwasher without a change in water temperature or flow.

No question about the benefits of the electric heater..........the problem is the huge cost increase.

BTW, a 1/2" line will flow far more water than the furnace, or the electric water heater, could possibly make.

That maybe so with an unrestricted outlet, but that's why we have a 40 gallon tank of hot water. Pressure drop caused by more than one consumer is the problem and increasing flow minimizes that.
I still think the increase in your rental electricity use is due to something other than a new water heater.

Unless you've got a four bathroom house, there is no possibility of suffering from insufficient hot water flow with 1/2" piping. The reason for the 40 gallon tank has nothing to do with quantity..........it's there to maintain temperature for 20 minutes at a "reasonable" flow rate...........maybe 2 gallons per minute.........max.

Take a look at the supplies for the sinks, the DW, and the toilet. Tell me what you find.........

I know taking a shower when the DW or clothes washer was running was unwise. Re-plumbing changed that. And I don't know how the number of bedrooms would affect hot water use or flow. On the otherhand, I don't use 500 kwh a month of electricity to keep my hot water hot.

If that's so, how does a tankless heater make sufficient hot water?