Calculation formulas
To calculate how much energy a boiler consumes, you should take into account its volume, the time it takes to heat water and the power of heating elements. You can see all this data in your passport, but when choosing on the Internet, there is no such option. Therefore, the easiest way is to calculate the consumption yourself.
To calculate the water heating time, we use the formula: time = 0.00116 * volume (hot water temperature - tap water temperature) / power. From here it is easy to calculate how much electricity will be spent on this by multiplying the operating time by the power of the heating element.
Taking an average family of three, which consumes about 200 liters per day, we calculate the estimated energy consumption per day by dividing 200 by the volume and multiplying by the electricity for one tank. Multiplying the resulting value by 30, we get the number of kilowatts that will be required per month to maintain the hot water supply. The cost of maintaining heat in the standby state can be ignored because it is minimal.
How much electricity and money will a boiler use?
Electricity is the most expensive energy source, but how much will a regular boiler empty your pocket? Costs will directly depend on how much hot water we consume and what its temperature is... How much does it cost on average for a boiler (storage water heater) for a family? How to save money when using a boiler, and which one will be the most profitable?
How much electricity is consumed per month?
How much hot water is consumed per day and per month? From what temperature to what temperature will we heat it?
Let's take the average statistical data: hot water consumption per day is 100 liters (3000 liters per month), its temperature is 60 degrees, cold water temperature is 10 degrees.
To calculate the energy consumption for heating water, we will use the simplest empirical formula. W=0.00116 * V (T2 –T1), Where V – volume, 100 liters, T2 – final temperature, 60 degrees, T1 – initial temperature, 10 degrees. We get W=0.00116 * 100 (60 –10) = 5.8 kW per day, or 174 kW per month.
But part of the energy from the boiler will be transferred to the air when it cools, while the water heater will turn on and maintain the temperature at a given level... It is believed that a modern storage water heater produces on average no more than 0.5 kW for heating a room per day. Then the daily electricity consumption for heating water will be 5.8 + 0.5 = 6.3 kW, and for a month - 189 kW.
The numbers of this calculation are not so small in the end. It turns out that you need to pay almost 1000 rubles for electricity for one month, at a tariff of about 5 rubles/kW. And this is only for one boiler, not taking into account other energy consumption.
In reality, the operation of the boiler is in 90% of cases more economical than according to the standard calculation given here. How to reduce water heater costs?
How much energy does a storage water heater actually consume?
Real numbers can only be provided by statistics, and not estimated data on flow and temperature. What do you save on when using a boiler?
Typically the water temperature is much lower than 60 degrees. After all, such heating is very hot, suitable for taking a bath, and from the tap it will burn. It is not needed for washing dishes... If a shower is not planned, then zealous householders heat it to only 20 - 25 degrees. Cool water is quite comfortable in the kitchen...
The actual consumption of hot water per family, with a very economical approach, is very small - about 30 liters of water at 20 degrees (heating by 10 degrees) - and this is all in a day. If there is a shower - about 10 liters of 45 degrees per person - a total of 30 liters, plus 20 liters for other expenses...
And only taking a bath entails serious heating and consumption...
- In general, with very economical operation, you get only no more than 50 kW per month per boiler.
- With moderate savings - about 100 kW per month per boiler, and accordingly, 500 rubles...
What boiler volume is the most economical?
The fact is that with very economical operation, consider “heating only when needed,” the excess volume of the boiler becomes somewhat wasteful. Hot water that is not used for its intended purpose will eventually cool down and give off heat for heating the home. The excess consumption will not be the conventional 0.5 kW, as in the calculation, but the entire 2.0 kW per day, for example... But with active use, “water is always heated to the maximum and there is a high flow rate,” this almost loses its significance...
Therefore, for big savings with a boiler, its volume should be minimally realistic. But at the same time, it should not cause great inconvenience in terms of lack of hot water.
It is best to use practical recommendations from operating experience and from specialists.
- It is stated that, on average, for a family of 3 people, 80 liters will be sufficient, but you can also save a lot of money with it.
- For a family of 4 - 5 people, 100 liters is better to minimize delays with the shower...
- For serious savings, it is better to limit yourself to 50 liters, and heat them occasionally to the desired temperature, and a boiler of this volume will be the cheapest...
- Fans of water procedures who do not care about energy saving should think about volumes from 120 liters, with a heat power of more than 2.0 kW.
Characteristics of boilers with a capacity of 50 liters
Let's take three 50-liter devices with different parameters and calculate their effectiveness. For everyone, let’s assume the temperature of the tap water is 15 degrees, and the hot water is 60 degrees. Daily consumption will be 200 l.
The Ariston ABS VLS EVO PW 50 water heater has two heating elements of 2500 watts. The heating time for a full container is 0.00116*50*(60-15)/2.5 = 0.928 hours, which is about 55 minutes. Daily consumption will be equal to 200/50*0.928*2.5 = 9.28 kW per day. This is 278.4 kW per month.
Boiler Ariston ABS VLS EVO PW 50
Electrolux EWH 50 Centurio DL is equipped with two heating elements of 1 kW each. All water is heated in 0.00116*50*(60-15)/2 = 1.3 hours, which is approximately what is written in the characteristics of the device. Per day this is 200/50*1.3*2 = 10.4 kW, 312 kW per month.
Boiler Electrolux EWH 50 Centurio DL
Ariston ECOFIX 50V 1.2 K is equipped with a 1.2 kW tubular electric heater. Time for heating is 0.00116*50*(60-15)/1.2 = 2.17 hours. 200/50*2.17*1.2 = 10.4 kW will be collected per day, 312.4 kW per month.
Boiler Ariston ECOFIX 50V 1.2 K
Comparison of models with a volume of 80 liters
Let's take the daily norm as 250 liters, which is enough for 4 people.
Ariston 80V 1.2 K for 80 liters with a 1200 W heating element heats the full container in 0.00116 * 80 * (60-15)/1.2 = 3.48 hours. 250/80 * 3.48 * 1 are consumed per day ,2 = 13.05 kW, which will be 391.5 kW per month.
Boiler Ariston 80V 1.2 K
Electrolux EWH 80 Formax DL has two 2000 W heating elements. The entire container heats up in 0.00116*80*(60-15)/2 = 2.088 hours. 250/80 * 2,088 * 2 = 13.05 kW are consumed per day, in 30 days the result is also 391.5 kilowatts.
Boiler Electrolux EWH 80 Formax DL
Gorenje FTG 80 SM with two tubular heaters with a total power of 2600 watts. Water heats up in 0.00116*80*(60-15)/2.6 = 1.6 hours. 250/80*1.6*2.6 = 13 kW are consumed per day, 390 per month.
Boiler Gorenje FTG 80 SM
Parameters of hundred-liter water heaters
We take a consumption of 300 liters per day, which is suitable for 5-6 living people.
The GBF 100 T/V9 100 liter burner has 1400 W heaters. Heating time 0.00116*100*(60-15)/1.4 = 3.7 hours. It will consume 300/100 * 3.7 * 1.4 = 15 kW per day, in 30 days 466.2 kW.
Boiler Gorenje GBF 100 T/V9
Bosch Tronic 1000 T ES 100-5 2000W BO L1X-NTWVB at 2000 watts will heat water in 0.00116*100*(60-15)/2 = 2.61 hours. 300/100 * 2.61 * 2 = 15.6 kW will be required per day, 469.8 kW per month.
Boiler Bosch Tronic 1000 T ES 100-5 2000W BO L1X-NTWVB
Atlantic O'PRO TURBO VM 100 D400-2-B at 2500 watts will heat all the liquid the fastest - in 0.00116*100*(60-15)/2.5 = 2.088 hours. It will consume 300/100 * 2.088 * 2.5 = 21.6 kW per day, and 648 kW will accumulate in 30 days.
Boiler Atlantic O'PRO TURBO VM 100 D400-2-B
You should also take into account the availability of a night rate. It may be more profitable to heat a lot of water at night and then use it throughout the day. In winter, the temperature of the water supply is much lower, which increases the heating time.
We can conclude that models with different parameters consume approximately the same electricity reading. At the same time, the price of powerful devices can be several times higher, which is explained by practicality - heating is faster.
Power of boilers of different sizes
If there are more people in the family, you need to increase these numbers by the required number of times.
The performance of the water heater depends on the volume of hot water that the family will consume per day.
To calculate it, you need to determine the number of water intake points. For example, a 30-50 liter tank will be enough for one person to wash dishes, wash his face and take a shower.
If there are more people in the family, you need to increase these numbers by the required number. So, a family of 4 people will consume from 120 to 150 liters of water daily. Based on this, you need to select the volume and power of the boiler, and also calculate energy costs.
It is not recommended to set the temperature to more than 50-55°, this will help reduce electricity consumption and also avoid the formation of scale on the heating element and other parts.
50 liters
The power of an average storage boiler with a volume of up to 50 liters is 1.5-2 kW/h. Electricity consumption directly depends on the operating time of the device. At these rates, the water will heat up for about 2 hours. That is, the daily electricity consumption will be 3-4 kW, which is equal to 90-120 kilowatts per month.
80 liters
If the amount of water consumed increases to 80 l/day, then you need a boiler with an appropriate tank volume and a power of 3-4 kW.
The heating time will increase to 3-3.5 hours. Energy consumption per day will be from 9 to 14 kW.
100 liters
For a family of 3 people you will need a tank of 100 liters. The productivity of such devices is 2-3 kW, and water can be heated from 3.5 to 5 hours. In such a situation, the water heater will consume about 300 kW per month.
