Five Minutes from 38 Gallons?

December 22, 2005 7:15 AM

WaterHeaterFilter: How much shower-time should I expect from my new electric water heater?

About two months ago, we switched from a 40-gallon gas water heater to a 38-gallon electric water heater. The gas lived inside the house, under the stairs, and had rusted a leak.

At first, we didn't notice much of a shift in performance. Showers were hot and life was good. But lately, I've been starting to wonder. Our morning routine goes like this: she showers, we eat a quick breakfast, then I shower. So this morning, I get in the shower, turn on the hot and add a slight turn of cold. Mid-soaping, I feel the water cooling, so I turn down the cold to nothing. Hot is back, but only for a short while. A bit more soaping and the hot is completely gone, leaving me to rinse rather arctic-ly.

After a call or two to the in-laws for advice over about half an hour (and checking the heater itself under the house for leaks - there were none), we unscientifically timed the hot water. I shaved and had hot water for five minutes. Then I ran the shower. After about six minutes, cold started taking over again.

So tell me ... were we just spoiled to our gas water heater's constant temperature? Or might we have a problem? One solution posed was installing a second electric water heater that would stay at 100 degrees. It would fee the main water heater (at 135 degrees), thus giving the main an easier time. Good idea?

(And while I have your attention, anyone have a decent low-flow shower head to recommend in the interim?)

posted by grabbingsand to Home & Garden (16 answers total)

Almost all shower heads these days should be 2.5gpm "low-flow" ones, the packaging doesn't even say it anymore because it's just standard. In the unlikely event that you have a 6gpm one, you can replace it. (To find out, run water into a bucket and time how long it takes to fill the bucket.)

Probably your electric heater is just set to a lower temperature than the gas one was. Before, you were using 50-50 hot water and tap water (1.25gpm of hot water...). Now you're using 95-5 hot water-tap water, because the hot water is cooler, so the heater empties quicker.

Find the heater's controls and turn it up a bit. Problem will go away.
posted by jellicle at 7:29 AM on December 22, 2005

Low flow shower head and though it will cost you a tiny bit more, turn up the temperature on you present tank. These two together should cut down on your hot water usage enough to get two showers.

You could also start going for communal showering?
posted by Pollomacho at 7:50 AM on December 22, 2005

I think you have a problem with your water heater; I had a 40 gallon electric heater (that's a pretty standard size) and never ran out of hot water, even with 30 minute showers. If the thermostat is at 135, that is well within the operating range and you should notice no difference from the gas heater with normal use. Are both heating elements working? Is there an obstruction somewhere? If you do not know basic plumbing, I would give whoever installed it a call.
posted by TedW at 7:51 AM on December 22, 2005

(Wife here)
1) I know that the temp is set slightly above what it came set from the factory, because my father installed it and I was told they'd increased the temperature slightly when it was done.
2) This didn't show up quite so much before we had a power outage last week. I wonder if the heating element didn't get damaged when the power went out. How do we check for that, or should it be fairly obvious?
posted by Medieval Maven at 8:07 AM on December 22, 2005

Another thing to check is the timer. My electric hot water heater has times to set when the temperature is hot. Basically, you're telling the heater to heat up in the morning for showers, then drop a few degrees during the day, then warm up for dinner, then back down. Just a thought.
posted by kungfujoe at 8:09 AM on December 22, 2005

Ah, the timer! The timer got off when the power went out!
posted by Pollomacho at 8:10 AM on December 22, 2005

Response by poster: Does every hot water heater have such a timer? Or is this a fancy feature that only comes along with Cadillac-level models?
posted by grabbingsand at 8:27 AM on December 22, 2005

Here is a good page on troubleshooting electric water heaters.
posted by TedW at 8:28 AM on December 22, 2005

Just curious and maybe a little off-topic, but why switch from gas to electric?
posted by fixedgear at 8:45 AM on December 22, 2005

Gas is getting more expensiver. Also, we wanted to move it under the house to minimize the risk of flooding our main floor, and electric ones are not so expensive to buy. And, if we got a squat gas one to fit under the house, we'd then have to mess with running more gas lines under there, which would be incredibly annoying (I think we could have done it, but my dad was not the fan of messing with a gas line like that, and he's free labor. And they gave us the water heater because they're cool like that.). It also increases storage for us on the main floor, which is real issue for us in our house. The only bad thing is that there is no magical hot water during power outages. Otherwise it's been 99% fine until this incident.
posted by Medieval Maven at 8:58 AM on December 22, 2005

there is no magical hot water during power outages

That should only be true of prolonged outages. When my 40 gallon heater mentioned above died, I replaced it with an 80 gallon model. Last year I lost power for 3 days due to an ice storm and was able to take a tepid shower at the end of it. Of course ambient temperature and insulation make a difference, but for the typical shortage of a few minutes to hours you should still have plenty of hot water.
posted by TedW at 9:22 AM on December 22, 2005

I would find out right away if one of the elements is out. It should be pretty easy with a multitester.

I had an electric where one went out and not only did the performance suffer kind of like this, the other element ran *all the time* trying to keep things warm enough.

It wasn't until the $400 electric bill that I figured out something was up.
posted by SpookyFish at 9:27 AM on December 22, 2005

SpookyFish, I don't see how a failed heating element could increase your electric bill.

Here is a debugging guide for electric hot water heaters. It souds a little like this problem

Problem: Not enough hot water or water temperature too low.

When the top of the tank is hot the upper thermostat removes power from the upper heating element and transfers the power to the lower thermostat and heating element. If the lower thermostat is defective, then the lower portion of the tank will not be heated and the supply will be greatly reduced.

posted by Chuckles at 9:46 AM on December 22, 2005

One other consideration: Two months ago, it was warmer in Georgia, right? So to get that perfect temperature for a shower, you were mixing somethng like 140 degree water from the heater with 70 degree water out of the pipe. Now that it's colder, you might have 50 degree water coming out of the cold water pipe and so you have to mix *more* hot water with it to get your desired temp, which means you run out of the hot stuff more quickly. To make matters worse, the water going in is also that colder water as well so it takes longer to replenish.

Disclaimer: The temps quoted above are WAGs, but the general priniciple should hold true.
posted by Doohickie at 10:30 AM on December 22, 2005

Gas heaters recover a lot faster (like two - four times as fast) than the same size electric. IE: a gas heater warms the incoming cold water faster than an electric. There isn't anyway to fix your exact problem without going to either a larger tank or to a tankless heater. Or you could wait longer between showers.
posted by Mitheral at 10:39 AM on December 22, 2005

I know that the temp is set slightly above what it came set from the factory, because my father installed it and I was told they'd increased the temperature slightly when it was done.

"Slightly above" isn't much, as I like my showers to be killing-old-people-and-babies hot. My hot water heater has two thermostats, top and bottom, and I have them cranked up to just shy of the max.
posted by astruc at 10:43 AM on December 22, 2005