Water heater theory.

[Got_Nailed]

My parents have a new electric 55 gallon hot water heater made by State Select (I think). The house has well water and the temp of the water is normal about 45*F. Everyone in the house likes long hot hot showers. When I installed it I only turned up the thermostats a little.

When we were talking about hoe little cold water they were mixing in with the hot and they were running out of hot water to soon. I told them I needed to turn up the thermostat but he thinks it would cost more. I’m thinking you should have about ¾ hot to ¼ cold for a shower but right now there just barley cracking the cold.

What are the opinions or is there a theory about this. I am aware about getting burnt of the hot water heater.

 

[Jadnashua]

Typical water heaters don't have a great recovery rate. A normal showerhead runs about 2.5 gallons of water/minute. You can't totally empty a hot water tank, since the incoming cold water dilutes it. If you are lucky, you might get 70% or so out of it. Now, the heating element is on, trying to keep things hot, but it can easily be overcome by long hot showers, or filling a large tub.

Keeping the water very hot is dangerous, but is probably what they need to do to lengthen their time they can run the shower. Depending on the insulation in the heater and where it is (an unheated basement or a heated space), the higher the stored temp and the difference with the ambient air, the more losses you'll have - add some more insulation around the thing, and you'll overcome most of that, if not all. Yes, because of the stored loss while not using hot water will cost more, but you'll be able to have a longer shower....you make your decision, and pay the consequences.

My late winter incoming water temp is just above freezing...you think you have a problem taking a long shower!

If you run the thermostat higher than around 119-degrees, it is probably a good idea to put a tempering valve on the output to limit the max temp that can be fed to the lines.

The 1/4, whatever argument doesn't matter. You could put a thermostatically controlled shower valve in, and then until it didn't have enough hot water, it would maintain the set temperature forever. As the stored water reached the set temp, it would be using all hot water.

 

[Sponsor]

 

[hj]

hot water

It would cost more because he would be getting more hot showers. You pay for the water you heat and then use. If he has it set low the heater does not run very long, but he also runs out of hot water faster. If he sets it higher, it will run for a longer time to get hot and turn off, but he will have more usable hot water. As a practical matter, if he keeps it low and turns off the water as soon as it gets cold, or sets it high and mixes more cold with it, the cost will be about the same.

 

[Master Plumber Mark]

theoriea about water heaters

the theroy you are talking about is called
........Stratification......

the incomming cold water mixes with the wimpy luke warm
hot water in the tank and the temp of the water crashes far
too quickly for more than just one peson to take a shower.....


When I install a water heater I usually set the top thermostat
at 130 and the bottom one at 125.....and my customer signs off
on this.....

back in the 70s ....before everyone started sueing everyone for
everything, the water heaters were set at 140 from the
factory.......both top and bottom elements....

those were the days when water heaters were water heaters.......
and real men took hot showers...

now they are sent out set at lukewarm.....
and you got to turn them up yourself...


Remember you can have a fever of 104.....

a 50 gallon water heater set at a decent temperature
wil easily take care of a family of 5.... no problem....

its not going to cost you anything much higher than
the energy rateing on the yellow sticker claims.....

and the odds of someone getting scalded is probably more rare
than hitting the lottery....unless you have a special situation with
small children or very elderly people ...its no problem.


of course you if you really want to save some BIG money,
you could always just turn off
the heater and just take cold showers.....

this way you can be absolutely sure that no one will ever run that
terrible risk of being scalded, ....and you save money too.!!!

 

[Geniescience]

winter strategy: raise temp only in winter

once you know your two temperature settings, top and bottom, you'll be able to plan more.

Like hj said, the cost per shower is the same if it they are the same length of time, no matter whether or not you had extra hot mixed with a lot of cold or some other combination.

raising the HW temperature a bit, in winter, is a great way to counteract the colder incoming water in winter only. That's what I do.

david

 

[Got_Nailed]

The temp settings are hot and hotter. I don’t like the thermostats that came with this tank.

I’m planning on installing a new main hot water line in the basement sometime next month. It is only ½. But at that time I’ll pop in a tempering valve and I’ll insolate the hot water lines and more on the tank.

The tank is in there basement witch is about 50* during the winter.


Thanks for the info

 

[Plumber1]

Dont be a pansy, turn up the temp and be responsible.
Boy life was really tough 35-40 years ago when hot water was hot.
With little kids and old people around, you could always set the temp. back.
Dishwashers would rather have at least 140o + water, but since " Dr. Spock" and the glut of lawyers life has sure changed and this plumber thinks life was better before.

 

[Master Plumber Mark]

Bravo!! Well stated!!

What has turned everyone into such panzies anyway???

The fear of being sued by a lawyer I suppose...


the heaters used to come out of the factory set at
140 on top and bottom and before someone figured
out that they could get money from a lawsuit,
the world was spinning on its axis just fine.......

now everyone is afraid to fart without worrying about
the consequences.......


to put a tempering and mixing valve on top your water heater
is a total waste of money,,, and you have been totally brainwashed
by the safety police ......


Once the democrats take over again I expect that the next safety law that will probably go into effect.....

Force everyone to wear a crash helmet while they are driveing
their car......

 

[Geniescience]

common occurrence to empty HW tank

it is not unusual to hear about peopel emptying the HW tank. This is not new wither, as far as I know. Soaker tubs are more and more common too now. Regardless of temperature, they take more water.

Whether people mix cold manually or "automatically" with an extra piece of hardware down at the tank is not a serious cost or waste of money.

I'm in favor of more equipment. Having systems perform more of the required functions in a house.

David

 

[Jimbo]

Remember the 70% rule. A water heater will deliver 70% of its gallon capacity. Your 55 gallon unit will give about 38 gallons. At 2.5 gallons per minute, that would be about 15 minutes. You can increase the available shower time by increasing the temp, and then using a tempering valve to provide a safe temp to the shower.

 

[rudytheplbr]

Running out of Hot water

The best way to avoid running out of hot water while taking a shower is to remove that storagetank/heater and install a on-demand heater. If it is electric you will need a larger capacity electrical supply wire to the heater.
On-demand water heaters use more electricity when in use. When you stop using it, it shuts off and draws no electricty heating water and keeping it hot when not in use. Plus, you can fill a 'hot tub' w/o running out of hot water, take showers as long as you like, etc.
Good Luck
Rudy

EAT "WILD ALASKA SALMON" IT'S GOOD FOR YOU AND YOURS.!!!

 

[vaplumber]

The best way to avoid running out of hot water while taking a shower is to remove that storagetank/heater and install a on-demand heater. If it is electric you will need a larger capacity electrical supply wire to the heater.
On-demand water heaters use more electricity when in use. When you stop using it, it shuts off and draws no electricty heating water and keeping it hot when not in use. Plus, you can fill a 'hot tub' w/o running out of hot water, take showers as long as you like, etc.
Good Luck
Rudy

EAT "WILD ALASKA SALMON" IT'S GOOD FOR YOU AND YOURS.!!!

No. Stay away from the electric on demand heaters. Dont have any experience with the gas ones, but have heard only negatives about them, but I do know that you dont want an electric. These things can use more electricity than your entire household combined uses in a days time. Think about pulling any where between 60 and 90 amps each time you crack a faucet just to wash your hands or brush your teeth. Have had some experience with them in hotels and commercial/residential (appartments) applications.

 

[Randyj]

I don't know what effect it had on their utility bills...but.... I had a customer in a small hair salon complain that she was constantly running out of water. She had one 80 gallon HW heater running two 4500 w elements. To shorten the recovery time I replaced the elements with 5500 w heating elements and so far she has been very happy with the results... I didn't even turn up the thermostats so the water isn't getting hotter... just faster.

 

[vaplumber]

Had a customer who installed tankless electric's in a small appartment unit. Says that not only did electric bill increase by two fold, but also that required maintenance, which is required every 6 months, cost him over $200 on each unit. Each unit is on a 60 amp breaker for each appartment. Also have a commercial owner which installed a 90 amp unit, and says that this was the worse mistake ever made. I also have another establishment which has 2 natural gas fired units, and because there is only 1 local shop who services the gas units, and he charges premium prices, says he will be switching back to tank type units. Tankless may work great in some areas, but my opinion of them is very low.

 

[Bob NH]

Economical Capacity - Electric Hot Water

A second tank in series gets you another full tank worth of hot water. Because the second tank is supplied by the hot/warm water from the first tank, you don't have nearly as much of the "70% effect" that you get with a single heater.

The least expensive way to meet large hot water demands with an electric heater is to:
1. Use as large a heater as economically available (probably 80 gallons), and
2. Turn up the temperature to about 160 F, AND
3. Put a tempering valve at the outlet to the system, and if necessary
4. Put a second heater in series with the first, complete with the tempering valve.

If you have two water heaters in series, the tempering valve goes only at the outlet of the second heater.

For an existing system, the greatest gain for the expense is implementing 2 and 3 with your existing heater.

 

[Got_Nailed]

All of the tank less models I have seen are 3 poll 20 amp (60 amps).
I’m going to replace the hot water lines in the basement next week form 1/2†to 3/4†because of the presser drop. I’m going to pop in a tempering valve since in playing down there. Turn up the thermostats to 155*. I’m also going to add outlets for a second heater (preheater).

I was talking to them the other day and I think 4 people tried to shower in 45 minutes. I bet the water was running for 30 minutes of that.
With 2 tanks the preheater would be set at the lowest setting and the second at 150?

 

[Bob NH]

I would keep both stages at the maximum temperature that you want to operate the system. That is not an installation issue, because you can set the temperature later.

The objective of storage heaters is to store enough BTUs at a high enough temperature so that when the hot water from the heaters is mixed with cold water you will have enough gallons of water at the desired delivery temperature.

So for maximum delivery of hot water, you want to start at the maximum temperature in all of the storage.

The recovery rate on hot water heaters (4500 Watts) is about 30 gallons per hour (1/2 GPM) at 60 degree temperature rise. You can put 5500 watt elements in a heater on a 30 Amp circuit if your main is big enough to handle it. Two such heaters would pull about 46 Amps from your main and give you about 1.2 GPM recovery.

If your first heater is hotter than the second, then both heaters will come on together only when you have extended demand. If the first is set lower than the second, then both will come on whenever you draw a significant amount of water.

 

[Got_Nailed]

You do have some good point Bob. I will keep this in mind when I set the water heaters if I install a second heater.