Title: Electric Boiler for 2-Person Shower: Are 50L Models Enough? Tips, Recommendations & Brands

Hello. I know that there are many topics, but each of them is mostly from a few years ago. I live in an apartment where there is no free chimney for gas junkers.
So I have to install an electric boiler. Earlier, we somehow managed to heat the water on gas (a large pot). The financial situation has improved a bit and it's time to renovate the bathroom and buy an electric boiler. 2 people will take a quick shower every day and one every day older, so it can be concluded that the boiler is needed for 2 people. Is the 50l boiler enough?
And do you have any proven models on today's market. I found something like the ARISTON LYDOS ECO 50L 1.8kw heater. Will it be quite economical with a reasonable use of water?

Hello, there are three of us and a 50-liter boiler is enough if not all of us are dripping in one go.

Added after 2 [minutes]:

I have a new Aristona boiler (it has the same power for a month and is not the first of this company)

Thanks ... Two people will definitely not need hot water at once. I usually take a bath after 4 p.m. and the other person after 8 p.m. It is known more than once that they will need 2 people hot water, but I think that for 2 quick showers (wet the body) soap and rinse) there will be no shortage of hot water.

It is connected non-stop but the power consumption depends in total on:
- hot water consumption, this will be about 90% of the cost
- the standstill losses of the tank, i.e. its insulation class, amount to 10% of the costs

And while the standstill loss in the summer is simply wasted energy, which additionally raises you slightly the temperature in the room where the boiler is, which you probably don't need, in winter the same effect is not a waste. It is simply more expensive energy that will slightly raise the temperature in the bathroom during cold weather.

The boiler heats up and uses energy when, for example, you empty the entire boiler and must heat it up to the set temperature (it works for about several dozen minutes) or when, for example, there is no water consumption, but the water in it cools down slightly. The thermostat will then turn on the heater for a few minutes.

The bills are about PLN 70-100 more for electricity, per month. The more water you use, the more you pay. Comfort costs money. And have you not thought about a gas flow thermostat, even for gas from a cylinder (if you have the conditions to install it)? Investment costs higher, but bills approximately 30% lower. At the expense of a little worse comfort (some fluctuations in water temperature)

Possibly gas, but capacitive, eg Ariston SGA 50. Can work with LPG.

In my apartment, there is no free ventilation chimney for a gas heater. And with the electric boiler I came up with a way to buy a timer switch for the socket. Set it to turn on 2 hours before my shower (i.e. 13:00 to 16:00) and later (19:00). -21). Unless this break between 4:00 p.m. - 7:00 p.m. would be unprofitable. And set it up for the weekend somehow. The rest of the time would be off.

Then buy one, at least once a year, for the duration of the trip, etc., disconnect it from the power supply, but for a week the battery will hold back the memory instead of 4 years, it will last for 8 years:


Cost from 30-40 PLN

I have 2, including a very old one and it still works without any problems and the battery lasts for 4 weeks. I use electrofumigators against mosquitoes.

Electricity is an expensive medium for heating water directly with a heater, but if you do not have the conditions, there are actually no other options.

That's what I meant.

I would be interested in the G12as tariff. The cost of kWh is about PLN 0.20, which is as much as gas. I would buy a larger tank so that there would be hot water for the whole day and it would be heated in the night tariff 22:00 - 6:00. I think a 100 liter tank is the minimum. Especially how are the baths supposed to be. The rain shower in the shower needs a lot of water too. If there is a shortage of hot water, you can raise the temperature of the domestic hot water, taking care not to burn yourself. Pay attention to the power of the heater in the boiler, the power of the connection in the apartment and other receivers in the house so that the plugs do not break out.

The entire electrical installation in the apartment is new. Separate es for connecting the boiler. With the G12 tariff, it is not a benefit for me, I think, because many receivers work during the day and then there are higher costs per kWh. And as I wrote above, 2 quick showers a day and an occasional wash basin.

Added after 46 [minutes]:

I calculated the electricity prices in the g11 tariff and the prices in the g12 tariff in the ratio of 40% of the use of g12 and 60% of the g11 with a monthly consumption of 163kw, it turned out that in the g12 tariff the bill would be PLN 1 more expensive than in the g11 tariff.

For me, a 50-liter boiler is enough for two people. The dishes are washed by a dishwasher, so it is a significant saving of heated water.
It is controlled by the programmer presented above and works at different times of the day and week, according to the stabilized rhythm of life.
As I use the G12 tariff, the boiler is only activated in this tariff. The thermostat is set to maximum and it is basically the clock that corrects the temperature. And yes:
On weekdays, the boiler works from 5:30 to 6:00, providing a small amount of hot water for a quick morning toilet. Then we go to work and there is no point in heating the water. Then, in the night tariff, which is also valid between 1:00 p.m. and 3:00 p.m. (or 3:00 p.m. and 5:00 p.m.), the boiler heats the water to the maximum so that it will not run out when you return from work. Then it turns on for an hour and a half at 22:00.
At weekends, the "night" tariff applies 24 hours a day, and due to different lifestyle and switching times are different: 8: 00-11: 00, 14: 00-18: 00, 20: 00-21: 30.
It has not yet run out of hot water during normal operation.

This concludes from your statement that the heater in the boiler is running around 4h per day. With a 2000w heater it is around 8kw per day. With monthly use at a normal tariff, it comes out to about PLN 120 per month. It all depends on the ratio of kw in tariff g12 to g11. 50% / 50% is not very profitable. For me, 2 TVs are on all day, a refrigerator, at least 1 computer (2 in the evening), routers in the morning, a vacuum cleaner. For me it would be the ratio of 30% g12 and 70% g11 So it wouldn't be profitable, unless I'm wrong.

The boiler is much more comfortable than instantaneous water heaters. The consumption of electricity or gas would probably also be similar because flow heaters need a larger stream of water to start it and then to fluctuate the temperature depending on the water stream. It is totally inconvenient when washing dishes. Washing with a larger stream of water, in turn, causes greater consumption of water, which means that electricity and gas, unless someone puts water into a bowl and washes it or uses a dishwasher. This is when a flow-through heater would be better. Modern gas flow heaters have a temperature stabilization in relation to the speed of water better than the electric ones from several years ago (I do not know what electric models there are now on the market), but I suppose that the comfort of use will not match that of boilers.

@ loli1987; yes, the boiler is powered for 4 hours a day. The heater's power is 1.5 kW. Which does not mean that the heater works non-stop for these 4 hours. Because if it is only supposed to heat up relatively hot water, it turns off quickly. For me, the 2nd tariff is 37 groszy, taking into account transmission charges etc., and the 1st tariff is 65 groszy. So it gives the worst cost 45/78 PLN per month. It is actually a lot, much less because monthly bills are about PLN 150. And this includes, apart from heating the water, cooking, air conditioning and normal household consumption. But the fact is, I have between 70 and 90% of consumption in a cheaper tariff (depending on the season, because the heating is electric-heat pump).

So in my case it is better to stay on the 24-hour tariff.

loli1987 wrote:

I calculated the electricity prices in the g11 tariff and the prices in the g12 tariff in the ratio of 40% of the use of g12 and 60% of the g11 with a monthly consumption of 163kw, it turned out that in the g12 tariff the bill would be PLN 1 more expensive than in the g11 tariff.

But above, TomekO1976 wrote about the G12as tariff, and not about G12, because these are two different tariffs.

In G12as the daily rate is the same as in G11, but the night tariff 22-6 is cheaper and amounts to approx. PLN 0.10 gross per 1 kWh.
The downside is that the subscription fees are a few zlotys higher and the cheaper tariff only applies to extra kWh, i.e. if you currently use 12 x 163kWh = 1956kWh per year, the lower rate between 22-6 hours will only apply to consumption above 1956kWh per year.
By installing the boiler, you will increase energy consumption, so you will use a total of, for example, 4000kWh and energy above 1956kWh will be cheaper in the hours 22-6, because you will pay for these 1956kWh as in G11, regardless of the time of consumption.

loli1987 wrote:

So in my case it is better to stay on the 24-hour tariff.

In my opinion, in your case, it is better to switch to G12as, buy an electronic switch so that the boiler heats up between 22-6, but then 50l will not be enough to last 6-22 a day, so I would take 80 liters of it as a minimum and partially as a maximum, because there may be a problem with a larger boiler in the apartment.

You must remember that the 80 l boiler heats up usually less than 3 hours, but this condition takes place during the first start-up, because then only the water is heated to maintain the set temperature, so the heater will be turned on rarely and for short periods. It will turn on more often if there is water intake.
But if we limit the heater's working hours to 22-6, then it would have to be tested, because in the regular G12 you still have an afternoon window with 2 hours of cheaper energy, e.g. 13-15, and in G12as it is not and you have to wait until 22.

If on the electronic programmer you set the power supply only for 22-6 hours, then if the heater turns on at 22:00, the next turning on the heater may fall somewhere in the morning, where there will be no cheap energy and if you would like to use 100% cheaper energy, you would have to wait until 10 pm, which is almost 24h.

If I were you, I would play with the G12as tariff and appropriate control of the boiler heating cycles to make the most optimal use of the period of cheap energy 22-6.

That's how I understand everything. Only if such fun is profitable. If the 50l boiler heats up in 1.36 hours and uses half of its capacity during one shower, the heater will not turn on for a long time for the second shower after a few hours, so it will not be such a large cost to change tariff.

loli1987 wrote:

Only if it is profitable to have such fun

You count it yourself.
If you use, for example, 2000kWh of energy during the year, then in G12as during the night tariff it will be 2000 x 0.21 PLN = 420 PLN.
In the case of G11, it will be 2000 x 0.52 = approx. PLN 1040.
The difference in the subscription between G12as and G11 is a few zlotys, you can assume that you will pay about PLN 50 more for the G12as per year.
If you want to have exact amounts down to a penny, count yourself according to the price list of your Power Plant and judge for yourself whether it is worth combining for these several hundred zlotys a year.
Of course, if you use more water, you will have more kWh than I assumed for the calculations, if less, then you will get a bit smaller amounts to pay.
And the above calculations apply if we use 100% of the energy on domestic hot water in the night tariff in G12as, because if you mix the night and day tariffs, the differences will be different, i.e. smaller.

loli1987 wrote:

If the 50l boiler heats up in 1.36 hours and uses half of the capacity with one shower, the heater will not turn on for a long time for the second shower after a few hours.

Heating up for 1.5 hours is only performed once when the boiler is started for the first time, because then the water will be warm all the time and only energy losses will be replenished.
If you empty the boiler 50% of hot water, the other 50% will be filled with cold water from the mains, so the average water temperature will drop and the need to heat up may be faster than you think. And if you would like to use 100% of the night tariff, more water is needed in the boiler to keep it at a comfortable water temperature until 22 when there is cheaper energy.

loli1987 wrote:

So it will not be such a large cost to change the tariff.

For me, these few hundred zlotys are enough incentive to try to figure out how to use the G12as only in the night tariff.
As for the domestic hot water, the 80l boiler can serve 3 adults, but in the G12 tariff with an afternoon window for 2 hours of cheaper energy.
I do not have any practical examples with the G12as tariff, so I do not know how much the 80l boiler would prove itself in practice, so it is definitely a kind of blind purchase, with no guarantee of success.

Does such a tariff change cost something? And in a bad communal apartment there will be no problem with changing this tariff. So now I was thinking that I would probably take an 80l boiler, it is only a few dozen zlotys more expensive.

Changing the tariff without changing the ordered capacity, as a rule, does not involve additional fees, or some costs of several dozen zlotys related to the replacement of the meter. A larger boiler means more losses, so it's worth considering. Taking a shower usually does not use up a terrible amount of water - washing it under running water is the worst.

Now I am stupid, when I switch to the g12as tariff, the heating of the 50l boiler in the night tariff until 6 am will be enough for a shower at 3 p.m. and the second after 8 p.m. And it seems that he will have to heat the water before 8 p.m. And the 80 l boiler set to more My reasoning, I should keep the water warm enough until 8 p.m. to comfortably take a second shower. Next week I start renovating the bathroom and I have to decide on the capacity of the boiler, because I have to install additional reinforcements on the wall where it will hang.

I have a shower and I have thrown the bathtub out. Until now, I had a flow water heater. I got rid of him too. I bought a 30-liter boiler and it is enough for two people. 1.5KW heater. First, I was heating the water non-stop, but when I started to control the meter, it turned out that when I turned on the boiler for, say, an hour before the planned bath, I save about 1KW of electricity. It takes practically half an hour for the water to warm up to the set temperature. The only drawback is that I have to turn the boiler on and off every day.

I will also pay attention to two important things when using the boiler. First, it is not economical to store large amounts of hot water. The more of this water, the larger the surface of the device and the greater the heat loss. The daily heat losses are a parameter given by the manufacturers of such heaters.
The second fact is related to the first. From the point of view of economy, it is advisable to set the temperature as low as possible, because the greater the temperature difference between the boiler and the environment, the more intense the cooling. But there is the other side of the coin. Firstly, very hot water is mixed with cold water, and as a result you get a much larger amount of water for use. In addition, very dangerous Legionella bacteria grow in boilers used with low temperatures. Also for hygienic reasons, it is worth keeping the temperature in the water heater high.
Regarding the two tariffs, in the G12 there is also a "window" of cheap energy. From April 1 to September 30 it is 15-17 hours, and from October 1 to March 31 13-15 hours). Find out what it is like in your region and available tariffs.

You would need a time switch, which you will also buy about which the Governor wrote in his post. I hope that the costs will increase by about several dozen zlotys a month.

loli1987 wrote:

The industry still has no choice but to choose and whether to change the electricity tariff.

As for the G12as, you don't have to wonder whether you are taking it now or never.
G12as takes into account the annual energy consumption of the 12 months preceding the tariff change to G12as and this amount will be your fixed limit for the entire duration of the contract, above which you will only have cheaper energy at night.

If you currently have "low" consumption, it now pays to switch to G12as before increasing that consumption.
If you start the electric hot utility water boiler now and want to choose G12as only in a year, then you will have a kWh limit taking into account hot utility water, so you will gain nothing and changing to G12as will be pointless
In short, changing to G12as makes sense only when we plan to increase electricity consumption, e.g. for heating domestic hot water and / or for heating.

You can change the tariff once a year, so if after a year you find that G12as is not particularly profitable for you, you can choose something else, go back to G11, or choose another from the G12 group.
My tariff change is free of charge. You pay to increase the contracted capacity, i.e. change from a 1-phase to a 3-phase installation, etc., and then you pay several dozen zlotys one-time fee for each 1kW of additional power.

Forget about a quick shower for 2 people with the 50-liter boiler. This amount of water is needed for a bath for one person. Also take into account that it takes about 1.5 hours to heat up the next portion of 50 liters for another person. This is how long the other person will have to wait for the water to heat up. Theoretically, you can heat up to a higher temperature and mix hot and cold water, but this temperature is limited to around 60'C. Above, intensive limescale precipitation will start, which will clog the boiler, pipes and batteries.
If there is only a shower, then a boiler of 80 liters is the minimum for 2 people to take a quick shower one after the other. If there is a bathtub, then a minimum boiler of 150 liters.

When it comes to 2-tariff electricity, it only makes sense when it is possible to organize life in such a way that DHW heating, washing and ironing take place during the hours of the second tariff. You should also know that in the case of double-tariff electricity, electricity in the first tariff is slightly more expensive than single-tariff electricity.

Plumpi wrote:

When it comes to 2-tariff electricity, it only makes sense when it is possible to organize life in such a way that DHW heating, washing and ironing take place during the hours of the second tariff. You should also know that in the case of dual-tariff current, electricity in the first tariff is slightly more expensive than single-tariff electricity .

This applies to the tariff, for example G12, G12w, where it is like you write about the differences in prices for "day" and "night" electricity.

On the other hand, the G12as tariff is an exception, where the daily electricity price is the same as the electricity price in the G11 24-hour tariff.
We lose only a few zlotys a month on the higher subscription fees in G12as compared to G11, but it is enough to heat the hot tap water in the hours 22-6 for this tariff to make sense. You do not need to iron, wash between 10 p.m. and 6 p.m., but of course, in order to increase profitability, you can change your habits as long as we generate additional kWh above the limit we used before switching to G12as.

Plumpi wrote:

Forget about a quick shower for 2 people with the 50-liter boiler.

Well, the opinions are divided. As a colleague, "Zybex", I write that even a 30-liter boiler is enough for a 2-person shower.

loli1987 wrote:

Again, when I think about 80l, someone else advises against it because the daily losses will be greater, etc.

As a rule, it is correct, the larger the tank, the greater the heat exchange surface and the greater the standstill losses.

But it all depends on how good the thermal insulation of such a boiler will be and what will be the catalog downtime losses, and contrary to appearances, it is not easy to find these data for electric boilers.
You will find this parameter sooner for hot water tanks for central heating boilers
For example, the Termet ZWU200 / N hot utility water tank has a standstill loss of less than 34W, which gives about 0.81kWh / day, and the tank itself has a capacity of 200 l and belongs to the energy class A.
Also, the capacity is not everything, but the fact that with electric power I would not expect such low losses.

Overall, I would care about the losses, they are and will be, but the difference between 50 and 80 liters will not be colossal, but rather small, so negligible.
Once a week, it is worth taking care of heating to, for example, 70 degrees, as an anti-legionella mode and it is worth thinking about the mixing valve at the boiler outlet, thanks to which you could in theory have even 90 degrees in the boiler, you will not get more in the tap than you set on the mixing valve, so you won't burn your skin, and I know a case when one person almost boiled themselves in boiling water from the boiler.

I have a 40-liter boiler and it is enough for 2 people with my wife, taking a bath one person after another, but this is the maximum of its possibilities. After bathing, the water is cool. Warming up takes approximately 2 hours until the thermostat is turned off. I keep the temperature of 50 degrees Celsius in the boiler and do not turn off the boiler, it works non-stop. Perhaps I am lucky that the boiler keeps the heat well and does not turn on as often as the one I had before.

Kenworth 18 wrote:

I have a 40-liter boiler and it is enough for 2 people with my wife, taking a bath one person after another, but this is the maximum of its possibilities.

I don't know if I'll count correctly but ...
40l of water heated from 10 to 50 degrees Celsius will store approx. 1.86kWh of energy.
This amount of energy is enough to obtain approx. 57 l of water heated from 10 to 38 degrees without taking into account downtime losses.
Assuming a water flow of 8l / min, we have water for approx. 7 minutes of showering.

7 minutes of continuous water intake may be enough for 2 people to take a quick shower, but it may as well not be enough for a shower for one person.
It all depends on who is taking which shower, because as you know, shower is not equal to shower.