How to calculate how much electricity an electric heating boiler consumes

It is impossible to determine the exact consumption of an electric boiler, since it depends both on weather conditions, the location and parameters of the house, as well as on operating conditions and the functionality of the automation. However, calculating an approximate figure and presenting the approximate amount to pay for heating a private house with an electric boiler is quite simple. At the same time, not everyone knows that energy consumption can be reduced by 10, 30, and sometimes even 50% by resorting to small, quickly recouping costs, which are described in detail in this article.

We calculate how much electricity an electric boiler consumes per hour, day and month

Almost all modern electric boilers have an efficiency of 99% or more. This means that at maximum load a 12 kW electric boiler will consume 12.12 kW of electricity. Electric boiler with a heating capacity of 9 kW - 9.091 kW of electricity per hour. Total, the maximum possible consumption of a 9 kW boiler:

1. Per day – 24 (hours) * 9.091 (kW) = 218.2 kW. In value terms, with the current tariff for the first half of 2020 for the Moscow region - 218.2 (kW) * 3.89 (rubles per 1 kWh) = 848.8 rubles / day.
2. The electric boiler consumes 30 (days) * 218.2 (kW) = 6,546 kW per month In value terms – 25,463.9 rubles/month.
3. For the heating season (suppose from October 15 to March 31) – 136 (days) * 218.2 (kW) = 29,675.2 kW. In value terms – 115,436.5 rubles/season.

However, a boiler unit correctly selected for power never operates at maximum load 24/7. On average, during the heating season, an electric boiler consumes about 40-70% of the maximum power, that is, it works only 9-16 hours a day. So, in practice, in an average brick house of 70-80 m2 in the climatic zone of the Moscow region, the same 9 kW boiler requires a consumption of 11-15 thousand rubles per month.

How to calculate the required boiler power Individual calculation, formula and correction factors

What does an electrode boiler provide?

The very idea of ​​an electrode boiler is this. to refuse the use of heating elements. If you now look at the diagram of an electrode boiler, you will see that electric current passes through the coolant from the electrode, which is supplied with voltage to the body of the boiler, which is also a conductor.

It turns out that instead of a heating element, the heating element here is the coolant itself, which is heated by the movement of negatively charged particles (ions).

Of course, any competent electrician will say that in reality there is no movement there. But for us this is completely unimportant now.

What is important is that losses in this case are minimized. And thanks to this, the electrode boiler has an efficiency of up to 97 percent. Where do these same 3 percent of 100 go, I wrote to you a little higher.

It is important for us that, all other things being equal, an electrode boiler will consume slightly less electricity than a classic boiler with heating elements. This time.

Secondly, the process of heating the coolant itself occurs faster, because when the electrode boiler operates, the entire volume of water is heated at once, and not just the layer next to the surface of the heating element.

But in such a scheme there are not only advantages, but also disadvantages. You will read about them below, in the “Reviews” section.

Consumption based on house parameters

A visual representation of heat loss in a private home.
You can more accurately estimate the possible power consumption of an electric boiler by knowing the parameters of the house and its heat losses (also measured in kW). To maintain a comfortable temperature, heating equipment must replenish heat loss in the home. This means that the heating output of the boiler = the heat loss of the house, and since the efficiency of electric boilers is 99% or more, then, roughly, the heating output of the electric boiler is also equal to the electricity consumption. That is, the heat loss of the house approximately reflects the consumption of the electric boiler.

There are averaged data on the heat loss of houses made of various coating materials (houses with a ceiling height of 2.7 m, a standard glazing area, located in the climatic zone of the Moscow region are taken into account). The temperature difference is taken as 26°C (22°C in the house and -4°C outside), this is the average value for the heating season in the Moscow region.

Reviews from owners of electric boilers about performance in practice

According to installation practice, reviews from owners and information from forums, we were able to obtain many examples of a wide variety of designs and consumption indicators, here are some of the most illustrative examples:

• The house is 160 m2, it costs 18-20 thousand rubles a month, but this is Siberia. Wall: expanded clay block + 5cm penoplex + brick lining.
• The house is approximately 165 m2, frame, insulated with PSBS-15 150 mm thick, roof - PSBS15 240 mm thick. We’ve been living in the house for the first year, so we haven’t gotten around to finishing the house yet, plus there are problem areas such as the iron entrance door, which freezes, and the uninsulated staircase in the 7 m2 basement. In total, 15,865 kilowatts were consumed over 141 days of the heating season.
• Area 120 m2, floor - 150 mm eps, ceiling - 300 mm glass wool, wall - 375 mm D300. Ventilation - 6 pieces of Blauberg A150 Pro ventilators + 150 mm supply pipe in the boiler room. For the calendar year from 03/09/2018 to 03/09/2019 - 16,812 kW. We consider 16812/120/365/24 = 15.99 Wh/m2.
• House 50 m2, standard 2-brick masonry and plaster without insulation, plastic windows with double glazing. The monthly cost is about 7-9 thousand rubles per month in winter and 5-6 thousand rubles in autumn/spring, at 0 degrees or above zero.

Efficiency and selection criteria for energy-saving electric heating boilers

What determines the actual power consumption?

The most significant power consumption of an electric heating boiler depends on:

1. Operating conditions . Namely, on the desired temperature regime (a decrease in temperature by 1°C implies up to 5% savings), constancy of residence in the house and regulation of indicators during sleep or absence of the owners of the house.
2. Technical condition of the boiler . Namely, its heating elements (tubular electric heaters). When using hard, untreated and constantly replaced water as a coolant, scale forms on heating elements, which reduces efficiency from 99% to 90.80 and even 70%. To heat the coolant to the previous temperature through a layer of scale, the electric boiler requires more energy and time.
3. Equipment . The circulation pump and advanced automation consume from 60 to 150 W. However, these are not so significant values ​​​​against the background of already expensive operating costs.
4. Automation functionality . Advanced modern automation has several operating modes, more competently controls the switching on and off of heating elements, the operation of the circulation pump, smoothly regulates the temperature, and allows you to set hysteresis values. Electric boilers in the middle and higher price categories are often equipped with the ability to program the operating mode, which significantly affects consumption.

The best known manufacturers and models: characteristics and prices

heating elements new

Ionic

Induction

Poll: what type of electric boilers did you choose?

The two best ways to reduce electric boiler consumption

How to choose an external thermostat for an electric boiler and save up to 30% on heating every month

If the automation does not provide the ability to program the operating mode, you can seriously reduce the energy consumption of the boiler by connecting a programmable room thermostat to it (if there are appropriate contacts, information about the possibility of connecting external control is always indicated in the technical specifications).

A programmable room thermostat controls the operation of the boiler based on measurements of the air temperature in the room in which it is installed, and not on the temperature of the coolant. However, the main and most important task for saving purposes is the programming mode of work settings for the next day and week. For example, during working hours when the owners are away from home, you can set the temperature to 15°C. And during sleep – 18 or 19°C. Such parameters will not affect comfort, but will significantly reduce the final energy consumption.

The second indispensable element when heating with an electric boiler is an electric meter, which differentiates electricity consumption by two, or better yet, by three time zones. For example, for the Moscow region the following tariffs are differentiated by time zones:

• peak zone (from 7:00 to 10:00 and from 17:00 to 21:00) – 5.06 rubles per 1 kWh;
• half-peak zone (from 10:00 to 17:00 and from 21:00 to 23:00) – 3.89 rubles per 1 kWh;
• night zone (from 23:00 to 7:00) – 1.68 rubles per 1 kWh.

In practice, the costs of purchasing, designing and installing a metering device that differentiates consumption pays off in a few months, since it reduces costs in monetary terms by 15-25%.

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