What is more profitable: boiler or hot water? – pros and cons + calculation example

At the end of this note there is a calculator with which you can independently estimate whether it is profitable for you to install a boiler or not.

Every year, planned hot water outages occur throughout the country. While there is time, you need to prepare and choose a boiler or water heater. Many people are starting to use it on an ongoing basis instead of the central water supply, I think it’s more profitable.

Let's consider how things really are. Is it profitable to use a water heater (boiler) instead of hot water from pipes, or is central water supply still cheaper?

Calculating the cost of hot water supply in an apartment

Almost every apartment has meters installed to determine the volume of monthly consumption of cold and hot water. If there are no meters, the following standards have been approved: in apartments with running water, sewerage, centralized hot water supply, with bathtubs more than 1500 mm long, equipped with showers, hot water consumption per person is 3 cubic meters.

The hot water temperature should be in the range of 50 ° C - 75 ° C. But on average it is heated only to 55 ° C. It rarely goes higher. You can easily see this for yourself if you try to measure the temperature of the water that comes out of the tap.

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Dry mathematics using real examples:

In Kyiv the cost of 1 cubic meter. m. (1000 liters) of hot water, if water heated towel rails are connected, is 84.45 UAH, if they are not - 78.08 UAH.

Without meter, with connected heated towel rail

There is a counter

For each person registered in the apartment, you must pay 253.35 UAH.
If three people are officially registered in the apartment, the amount is already 760.05 UAH.

Payment is 84.45 UAH. for 1 cubic m. hot water.

The volume of hot water consumption for a family of three (assuming that everyone uses a shower and not takes a bath) is 3 cubic meters. m. per month.

Thus, it is necessary to pay 253.35 UAH, but regardless of the number of persons registered in the apartment.

Conclusion: if more than one person is registered in the apartment, installing a hot water meter will allow you to save significant money every month.

Heater selection

This device has a number of significant disadvantages:

chimney required;
you need to obtain permission and call specialists for installation (self-connection is prohibited by law);
There is a danger of poisoning from natural gas or its combustion products (carbon monoxide).

But all these difficulties do not deter buyers, since gas is the most affordable fuel (subject to a centralized gas supply).

Of the gas water heaters, the most commonly purchased are instantaneous ones, which are commonly called geysers. As shown above, heating water using the flow method requires significant power, but household gas supply networks, as a rule, can provide it. Columns with a power of 24 - 30 kW are not uncommon, and there are also units with a power of 40 kW. Such an installation is capable of “pulling” the hot water supply of a large cottage.

Columns can be very different, but first of all you should pay attention to the ignition system. There are two options:

The column has a pilot burner (wick).
The gas in the main burner ignites from a spark, which is generated by batteries, a household electrical network or a piezoelectric element driven by a flow of water (a turbine is installed in the water pipe).

Boiler to replace centralized hot water supply

A boiler (from the English Boiler - boiler, boiler) is an electrical device for heating water collected in a tank. Instantaneous water heaters and boilers operating on other types of energy are not discussed in this article.

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Essentially, a storage boiler is a tank with a built-in heating element that uses electricity to heat water to a set temperature. The efficiency (coefficient of performance) of modern boilers is about 96%.

All this is understandable. The definition just does not indicate that the device not only heats water to the required temperature, but also maintains this temperature, like a thermos, but with the possibility of further heating. How long the water stays warm depends on the quality of the insulation. Those devices that our company offers retain heat throughout the day, and for this they use only 1-2 kW ∙ h per day.

It turns out that heated but not used water remains warm for a long time. And you save money, because reheating is not necessary.

Instantaneous water heaters

The electric appliance heats the water immediately when it is supplied. The clear advantages of a water heater are:

no waiting for water to heat up;
using electricity only while water is passing through it.

On average, the power of devices ranges from 5 to 12 kW. Electrical wiring in an apartment, especially in an old house, is not able to withstand such a load. In the best case, it will be possible to use a 5-kilowatt device, and no longer turn on any equipment during its operation. If possible, it is better to lay a separate electrical line.

Flow heaters are capable of changing the temperature by a certain value, which remains unchanged, for example, by 25 degrees Celsius. The temperature of the incoming water changes with the seasons. In summer it is 20 degrees or more, and in winter it can drop to 6-7. In this case, the tap will have water with a temperature of only 31 degrees.

How much does it cost to heat water with a boiler?

Initial data for calculations:

1) In Kyiv the cost of 1 cubic meter. m of cold water is 8,436 UAH.

2) Boilers with a capacity of 1.5 kW or more are available on the market. up to 3 kW. According to our statistics, the most popular models of boilers with a volume of 80 liters and a power of 1.5 kW

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Consider the cost of 3 cubic meters. m of hot water per month obtained by such a boiler using a conventional electric meter.

Cost of water	25,308 UAH
Electricity consumption for heating a boiler of 3000 liters of water (3 cubic meters) from a temperature of 15 ° C to 55 ° C with a boiler efficiency of 96%	About 145.38 kWh.
Cost of heating water (electricity 1.68 UAH per 1 kW*hour)	244.23 UAH.
Total to be paid (together with the cost of cold water)	269.54 UAH.

The amount received is almost the same as in the case of centralized water supply.

However, if you have a multi-tariff meter installed with a 2-zone tariff and your boiler operates from 23:00 to 7:00, then 3 cubic meters. m. of hot water will cost you as much as 147.43 UAH. (this already includes the cost of cold water). These figures are approximate and depend on many factors that, in principle, will not change it much.

Conclusion: we recommend buying boilers of the maximum capacity in order to heat a larger supply at night at a reduced rate. It is also beneficial to use socket programmers. the programmer physically turns on the boiler after 23.00 and turns it off at 07.00, so the boiler needs to be selected in such a volume that you have enough hot water for the period of increased payment for electricity.

As you can see, centralized hot water supply, even if there is a hot water meter, costs the consumer 1.7 times more expensive than heating water in a boiler that turns on at night (when using a multi-tariff meter with a 2-zone tariff). But before making a final decision, let's consider a few more facts.

Is it safer to turn off the boiler or keep it constantly running?

Modern electric water heaters are equally safe in any mode, both during continuous operation and when periodically plugged into the network. A normal, working boiler has several protection systems - a thermostat (often there are several), a non-return safety valve, and grounding to protect against electric shock.

Of course, if you plan to leave for several days, then the boiler needs to be unplugged. Like all other electrical appliances.

And a separate question - how do you turn off the boiler from the network? Do you pull the plug from the socket or turn it off with a button? If you constantly pull out the plug, this is dangerous, as it quickly leads to sparking of the socket and its destruction, which can lead to a fire due to faulty electrical wiring.

Advantages of centralized water supply

There are no additional costs for purchasing a boiler;
There is no need to allocate space in the bathroom to install the device;
Saving time and money on purchasing and installing a multi-tariff meter (if you don’t already have one).

Flaws

The water temperature rarely corresponds to the declared value;
Every year the hot water is turned off for preventative testing. The shutdown lasts from two weeks to three to four months.

Storage water heaters

Storage water heaters have a number of advantages:

connection does not require additional wiring;
the temperature in the tap is always at the set temperature;
high efficiency;
relatively low power.

There are also some disadvantages:

Long heating time;
Impressive dimensions and weight of the device;
Electricity is wasted to maintain the temperature in the tank.

Let's try to figure out what is cheaper - a storage water heater or paying for hot water by the meter.

Advantages and disadvantages of water heating devices

The disadvantages of boilers are limited by the installation time of the boiler - you will have to spend 2-3 hours on installation; as well as the need to allocate a place in the bathroom or toilet where the device could be placed. However, the design of modern boilers allows them to be part of any interior without violating its integrity and harmony.

The advantages are obvious: you can independently choose the desired water heating temperature, and use the remaining warm water for another day without having to turn on the device again. If you have cold water and electricity, then there will always be hot water, and it’s even cheaper than a centralized supplier.

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Preparatory work before installing the boiler

Self-installation of an electric water heater will cost you less than the services of specialists. On average, the work will take about two hours. But when preparing for installation and directly during the work process, safety regulations must be observed.

First of all, you should decide on the boiler model: what kind of system it should be - flow-through or storage, how many liters it is designed for, how it will be mounted - horizontally or vertically, on the wall or under the sink, etc.
The next step is to create a connection diagram for the device on paper indicating the connection of hot and cold water. Then you need to do the following:
check the strength of the wall for the ability to withstand the weight with a double margin (for example, if the boiler has a volume of 50 liters, then fasteners with a weight equal to 100 kg plus the weight of the empty boiler are required);
since the water heater is a very powerful consumer of energy, it is necessary to determine in advance the type of wiring (aluminum or copper) and the cross-section of the cable laid in the walls, and also evaluate the ability of the wiring to withstand the load of an electric boiler (for example, to connect a 2 kW boiler, a copper cable with a cross-section of from 2.5 mm2);
check the condition of water pipes and risers (especially for old houses) - they must be in good condition and have points for connecting a water heater.
Before you start installing the boiler, you need to read the instructions to understand the features of the model, then turn off the electricity and shut off the pipes supplying hot water. It should be remembered that if you live in a multi-storey building, this will temporarily deprive residents of other apartments of hot water, so you need to carefully prepare for the work in order to complete it quickly.

You can check the strength of the wall in the following way: mount the fasteners that come with the boiler and hang two bags of cement on it. If the mount can cope with such a load, then it will be able to withstand a water heater that weighs half as much.

Particular attention should be paid to checking the wall for strength when installing a large 150-liter boiler. Such a unit is fastened using expansion metal anchor bolts or special durable hooks

It is recommended to use anchors with a length of 100 mm and a diameter of 10 mm.

It should be borne in mind that installing the water heater will require the efforts of two people, since this process is quite labor-intensive. Typically, the boiler is mounted in the bathroom or toilet directly above the toilet. As a rule, this place is not used in any way. At the same time, a free approach to it must be ensured.

In a small room, to save useful space, the boiler is usually placed horizontally. A small-volume water heater is attached to the wall, and units with a volume of 200 liters or more are installed on the floor.

Most popular models

Which is the best water heater to buy in terms of the variety of models and additional functions, it is better to decide based on your budget. Here are the most popular representatives of flow storage devices:

Zanussi 3-logic 3.5 S is a fairly powerful and inexpensive device for practical owners;
Hyundai H-IWR1-3P-CS – has average power and all the necessary protection;
Electrolux NPX6 Aquatronic Digital is a good, powerful and expensive model.

Storage water heaters:

TIMBERK SWH FE5 50 – a flat, neat device with a powerful heating element and all the necessary panels and settings;
THERMEX FLAT PLUS IF 50V – the best ratio of cost and quality, wear resistance;
ELECTROLUX EWH 100 ROYAL is a safe boiler with a variety of electronic components and all kinds of protection.

All of the listed models have been tested by people and are used very successfully. Of course, there are cheaper options, but the quality may suffer. A “bad” boiler can heat up for a very long time, lose too much electricity and, in general, “eat” more money from the owners than the price for a high-quality model.

Control system

Electronic control

The device can be controlled and protected using a microprocessor. There is an LCD screen (possibly with a touch panel).

The required temperature regime can be set and adjusted using indicators and keys. In this case, the temperature can be set accurately, its value is displayed on the screen. Of course, this is more convenient, but repairs and purchase of such equipment will cost more.

Interesting fact! The price of a 30 liter flat electric storage water heater with mechanical control is on average 50-100% higher than with electronic control.

Simple mechanical thermostat

In simple models, a regular switch is installed, which can be in the form of a round regulator or a button.

The design is very simple, which ensures high reliability of the device

With its help, you can change the heating from 60 degrees to the desired degree value. It is impossible to set the exact temperature value; it will be displayed with an error of several degrees.

As a rule, these mechanical regulators are replaceable; you can often find an analogue in case of failure. Their replacement is simple and does not require the help of service specialists.

Dimensions

Depending on the volume of the tank, storage water heaters can be either compact or very large. In the first case, they can be mounted on the wall or hidden under a kitchen cabinet drawer. In the second situation, it may be necessary to allocate space for a separate room if it is a private house.

The larger the volume of the water heater, the larger its dimensions. Basically, the diameter of the tank is 45-55 cm. But the height depends on the volume.

Approximate Dimensions

Volume 50 liters - 50-60 cm.
80 liters - 75-85 cm.
100 liters – 100-115 cm.
150 liters - 140-160 cm.

The depth of the flat water heater is approximately 30 cm. But due to the decrease in size in depth, the height increases

The diameter of the slim water heater is 35-38 cm. They are very convenient to install in narrow niches. But as the depth decreases, the height increases.

with a volume of 50 liters the height will be 80 cm.
The 80-liter has 115 cm.
And with a volume of 100 liters – 140 cm.