[Solved] Flowing water heater - How much power should there be for the shower?

How much power should I buy an electric instantaneous water heater so that I can shower without fear of getting cold.

As large as possible to be installed in your electrical installation.

I am looking for a 1-phase one, I do not know if, for example, 5.5 kW will heat the water.

Added after 1 [minutes]:

Above, I would have to convert the installation to a 3-phase one.

5.5 kW is enough, there will be no warmth, but you will not be cold.

Do you have such power at home?

Added after 1 [minutes]:

I am looking for a practically proven heater.

Kuzyn had such and 3.5 kW for the sink. Complained that the shower was a bit too cold but it was bearable.

karopik wrote:

How much power should I buy an electric instantaneous water heater so that I can shower without fear of getting cold.

Take a 10l bucket and a thermometer. Give the shower that you currently need to wash well and comfortably from your current shower. Measure in how many seconds you will fill a 10l bucket with it and what is the water temperature. With this data, the required power of the flow heater can be determined.

Okay, I'll try tomorrow, does the inlet water temperature matter?

I have had an 18kW three-phase heater for several years and this is it. Full comfort and warm water. There is an "economy" switch on it and then it consumes less electricity, but it sneezes because the water pressure is poor.

Wait a minute, buddy. If you want a 5.5kW heater, and you have phase 1, do you want to turn off almost everything at home for the duration of a shower? 1 phase has a maximum of 5.7 kw, which is about 200 Watt, you have a receiver. It is, for example, in one room a 60 W bulb and, for example, a 75 W bulb in the bathroom, which already gives 135 W. Let's add a refrigerator that is always on and TV / household appliances on standby. This puts you on the verge of endurance. Have you thought what will happen when your pre-meter protection breaks down while you are in the shower? If I were you, I would consider 3 phases or preferably an electric boiler heated on the night (cheaper) tariff. I had to give up the heater myself in favor of the 80-liter boiler, due to the fact that I have phase 1. Let me just say that this boiler is enough for two people and washing the dishes

A shower with such a 5.5kW heater is naturally possible, but it will not be a delight, but just messing with a stream with the power of a medical syringe.
18 kW as much as possible.
That is why boilers were invented when someone does not have power conditions.

kwantor wrote:

That is why boilers were invented when someone does not have power conditions

Boilers have been produced for years, when no one was thinking about inventing instantaneous water heaters.

omen600606 wrote:

Let's add a fridge that is running all the time

,
It's not, unless it has a broken thermostat.

vodiczka wrote:

Boilers have been produced for years, when no one was thinking about inventing instantaneous water heaters.

I did not write that boilers are an alternative alternative to flow heaters - they are produced, were and will be, I do not need to write why.
Let me just mention that one of the undisputed features is the possibility of accumulating a large amount of highly heated water in the conditions of a small electrical power allocation.
I have pointed out to the author the only sensible source of hot water with non-choked outflow using electricity for his situation if he wants to take a pleasant shower.

vodiczka wrote:

It's not, unless it has a broken thermostat.

Not true, there are times when a refrigerator with a freezer compartment runs for several hours non-stop.
The stickiness and spite of the users, who rarely bring anything substantive to the topics, is the cause of the usual clutter of the forum.
I do the moderators here.
The question is in the subject - I know the topic from the practical side, I provide helpful information - this is the message.
Greetings.

kwantor wrote:

I have not written that boilers are an invented alternative versus flow heaters

You wrote: "That is why boilers were invented when someone does not have the power supply".
How should I understand that? Forgive me, I'm not picking on it, but I understand it unequivocally - boilers were invented for those who do not have power conditions.

kwantor wrote:

Not true, there are times when a refrigerator with a freezer compartment runs for several hours non-stop.

A few hours is a long job, but not "all the time"

Still the same..
How does it affect whether a few hours, 10 min. or 24 hours a day in terms of bathing?
That is why boilers were invented (among others) when someone does not have the power conditions. for the installation of a high-power heater.
So if I wrote that with the additions in bold, there would be no problem?
Heh ..

kwantor wrote:

Heh ..

And I thought that (electric) boilers were invented so as not to bother and get dirty when handling coal or wood-fired boilers. And they were invented in times when households did not have (or were to a small extent) three-phase power supply. And only after the spread of three-phase power supply, small-size, high-power flow heaters were invented as an alternative to electric boilers.

kwantor wrote:

How does it affect whether a few hours, 10 min. or 24 hours a day in terms of bathing?

In fact, it has no effect because taking a shower does not last longer than 10 minutes and during this time a slight exceeding of the rated load of the network (due to the fact that the refrigerator unit does not turn off) will not work.
fuse.

vodiczka wrote:

And I thought that (electric) boilers were invented so as not to bother and get dirty when handling coal or wood-fired boilers.

It is not true, it is a water reserve that allows you to be independent of the time of energy supply, it can even be coal .. it also allows you to save various types, including the use of the night tariff.

As for point 2, you have to sit by the fridge and wait for it to turn off and then run to the bathroom .. ??

karopik wrote:

Okay, I'll try tomorrow, does the inlet water temperature matter?

It has, but the worst value is taken for the calculations, i.e. 5 degrees in winter.

kwantor wrote:

As for point 2, you have to sit by the fridge and wait for it to turn off and then run to the bathroom .. ??

No need, I admitted you were right that the working time of the refrigerator does not matter because the power consumed by the aggregate is not large and it will not blow the fuses, let alone the pre-meter protections, another thing is to turn on the heater and oven or microwave at the same time.

kwantor wrote:

It is not true that it is a water reserve that allows you to be independent from the time of supplying energy, it can even be coal

Remember what you wrote: "That is why boilers were invented when someone does not have the power supply" and I wrote "(electric) boilers were invented not to bother and dirty when servicing coal or wood-fired boilers" I think I'm closer to the truth because from your entry you can it is presumed that flow heaters were produced earlier and boilers were invented for those who did not have power conditions.

So we will write endlessly? It's good - start the fridge, it's even 10A .. and it has an effect for the use of a heater that is selected at the limit of the power available in the apartment, while it has nothing to do with the operating time of the refrigerator what, how many turns on, how many breaks there are. What a colleague noticed so eagerly when he was making any attempts to deviate from the main topic, manifest and pursue some of his strange goals - perhaps putting himself at the heights of technical education: squarewink:
Nobody will depend on cooling and bathing - although there are priority relays. This is not what this is about.
And electric boilers were invented for reasons other than getting dirty ..
The fact that I did not list all the reasons for the invention of boilers does not mean that I did not write the truth, you have to "get it" a bit
I think someone will remove at least half of this topic by evening, off topic.
Please do not quote me anymore, because it is enough for me, as well as for my colleague's "doctorates" and the usual picking on ...

A few posts earlier it was written that one phase is max. 5.7kW. But such power requires adjusting the wires, meter and accessories to the load current of 25A (sic!). The cross-section of the wires must be appropriate. You cannot give a 25A fuse when the wires are only 10A, because they will burn and there will be a short circuit !!! In general, the installations are adapted to the current of 16A, i.e. the power of approx. 3.5 kW (a bit more). It was common (e.g. in the People's Republic of Poland) to provide 10A protection for the circuit of all plug sockets in the apartment (sometimes an automatic washing machine will crash, the more so as the refrigerator is not turned off from the socket) and also 10A to light (this is even more than necessary). As a result, fuses 10A have been changed to 16A (without changing the wires), but this must be in agreement with the electrician (cable strength, fuses in the stairwell, etc.). I am afraid that for 25A the cross-section of the wires must be at least 2.5mm2 (if not 4mm2) for copper wires.

Gentlemen, I know a little from the electric side because I'm an electrician. Please, someone tell me if the 5.5 kW flow heater will heat my water to such an extent that I can not wash myself comfortably. Boilers fall off because they heat the entire tank all day - I think it will be more economical [2 minutes in the shower is enough for me]

You've already got the comments, buddy.
I would not dare to install something like this in the shower - because:
I know the ones with the power of 3.5 kW; 5.5 kW; and 7.5 kW. with practical applications.
In order to wash a glass or dishes, it is 7.5 kW, so that the hot water flows somehow.
For this purpose, aerators are used in the spout, giving the illusion of a large stream.
Subject experts will quickly count and know what's going on - how much power you need to provide to heat half a glass of water to 40 degrees in 1 second (for example) it will be somewhere around 24kW with a large error.
This is how water flows in a real shower. Including yours as from a 4-hole window washer. What to talk about next and as an electrician you should know that.
Of course, this is the most economical NIBA method, but you need to have the power and know that
the boiler offers the possibility of using a tariff and a time clock, so it is debatable that it is expensive and loss-making - incidentally 1st. C a day ..

I have a boiler and I don't heat it all day, only 1.5 hours up to 70 degrees Celsius. So at the end.

The fellow quantor is right. I have a 5 kW heater to wash my hands in the outbuilding and I cannot imagine a shower with this amount of water. I set the flow so that it could be washed with relatively warm water, and it still annoys me that it flows so poorly. If you want, I will measure how long it takes to fill a liter jar, but it won't be crazy

Buddy quantor, you write nonsense, I have 5.5 kW in the sink and the water is hot that I can wash even very greasy dishes and in the shower I have 7.5 kW and I have to be careful about the water temperature, in the bolier you have 10 kW that it heats up so quickly?

Zybio 7.5 kw but 3-phase?

Added after 3 [minutes]:

Just 1-phase no more than 5.5 kw. And for 3-phase I have to convert the installation, then whether 5kw or 10kw does not matter to me.

no, two phases

Added after 49 [seconds]:

to avoid trouble in the kitchen is 5.5 kW on the third phase

Probably, without converting the installation to a 3-phase one, it will not be possible.

Zybio wrote:

Buddy quantor, you write nonsense, I have 5.5 kW in the sink and the water is hot that I can wash even very greasy dishes and in the shower I have 7.5 kW and I have to be careful about the water temperature, in the bolier you have 10 kW that it heats up so quickly?

Nonsense, buddy, you write maybe invite a colleague and demonstrate to him before thanking you for such advice.
Hot water will flow from each heater, the only question is how fast.
Also write how long it takes you to fill this sink with 40 degrees water.

Here you have the boiler: http://www.ekwasek.pl/index.php?products=product&prod_id=2062 I have a 2/4 kW switch.

And don't compromise yourself - a massacre. :crazyeyes:

karopik wrote:

then whether 5kw or 10kw does not matter to me.

Don't think, buddy, that even these 10 kW will be wasteful. 12kW is the absolute minimum.
You remind me of a guy who knows the word workshop and wants to put it in a crossword, at any cost, but nothing fits.
You know what I mean?
So the question is, why are you assuming the topic.
You will buy 5.5 kW and take a shower - your will, and the fact that this bath will look like the aforementioned crossword, with the word "workshop" is my fun now.
Greetings.

See in the DAF data how many degrees it heats the water, measure the temperature of the cold water flowing from the tap and you will see if 5.5 kW is enough, gives about 2.5 liters of water about 40 degrees heat

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DAFI