Buyers pay little attention to the power consumption of the dishwasher (hereinafter also referred to as PMM, dishwasher) that they choose. They are more interested in the design, size and other features of this technology. In fact, energy consumption, measured in kilowatt-hours (kWh), is one of the important characteristics of modern household devices.
The power consumption of modern dishwashers varies widely; read the article for details.
If a family washes dishes in a PMM every day, then with the low energy efficiency of the device, the owners will receive large electricity bills. And if we take into account the fact that tariffs are growing from year to year, the importance of economical use of electricity takes on special meaning.
What is the difference between power and energy consumption?
Many people confuse these indicators, but they are significantly different. You can notice this from the description of the characteristics of the PMM in the instructions. As a rule, the amount of energy consumption is less than power. What causes this? To understand the difference, you need to know how a dishwasher works. The fact is that during the dishwashing cycle, different components are involved at different stages.
Schematic representation of a dishwasher, which shows the main parts that consume electricity
Electricity is mainly consumed by:
- Electric water heater (hereinafter also referred to as heating element). In 10-15 minutes it heats the liquid to the temperature specified by the program. Heating can be carried out both up to +40℃ and up to +70℃. But the heating element does not work constantly; after heating the water to the required temperature, the thermistor (temperature sensor) sends a signal to the control unit and the part turns off. The power of the electric heater can reach 2.5-2.8 kW.
- Forced drying system for dishes . It also includes an electric heater, but it heats the air, which is forced by a fan into the working chamber. Convection drying takes longer, but it also consumes 35-40% less electricity than during forced drying. This process also takes only part of the total operating time of the PMM.
- The circulation pump (pump) supplies liquid under pressure to the spray arms throughout the entire time of washing and rinsing kitchen utensils. This part works the longest during the operating cycle. But the power of the pump is small - around 100 W.
- The drain pump removes dirty liquid from the PMM into the sewer. It does not work for long and has the smallest power, up to 30 W.
The circulation pump and flow-through electric heater are the parts that consume the most electricity in a dishwasher
Energy consumption is the amount of electricity used, expressed in kilowatts (kW), per hour of operation of the device. This indicator is expressed in kW/h units. But during this hour, individual energy-consuming parts can work in a matter of minutes. This is why the amount of energy consumption is much less than the power level.
The level of energy consumption depends on how much water is used for a full wash cycle, as well as on the selected program. The more water in the tank, the more energy and time is spent heating it. Work programs also differ greatly in the duration of dishwashing.
Power is the maximum amount of energy consumed in the shortest period of time (1 second), provided that all parts and systems of the dishwasher are working. Expressed simply in kilowatts (kW).
The two above indicators are usually recorded both on the PMM body itself and in the instructions for the device. They reflect a complete picture of how much electricity the dishwasher consumes. The efficiency of different dishwasher models is classified according to the level of annual energy consumption, and not by power.
Energy efficiency is divided into classes, the most efficient of which is A, the most expensive and outdated is G.
Why do some cars save money and others don’t?
The profitability of an electrical appliance depends on the energy efficiency and functionality of the individual model. Maximum consumption for the heating element, circulation pump and pump. But the main energy consumed by the dishwasher is the water heater, the second in terms of consumption is the heating element, which provides drying. In models that do not provide hot drying, energy is consumed more economically.
Important! Users are wondering which is more economical: using a dishwasher or washing by hand? Energy costs can be equal if you use a boiler to heat water. As for water consumption, with PMM you can save tens of liters daily.
If you need a machine that will wash efficiently and consume few resources, pay attention to options with convection drying - they require 40% less electricity.
Electricity consumption depends on the volume of the tank and the degree of water heating. The smaller the tank, the less water is used for washing - and you have to pay less.
Cost reduction is also possible when choosing models with innovative economy solutions. Thus, machines from the Bosch concern (as well as Miele and others) include a heat exchanger in their design. It saves thermal energy, and the device becomes as economical as possible.
Before you buy a dishwasher, you should know its energy efficiency. This is easy to understand from the simplest characteristics of the machine - look at the special information sticker indicating the class, indicated by a Latin letter. Judge by the letter how much the PMM will consume in Watts:
- A - 0.7-1.07 kW;
- B - 1.08-1.1 kW;
- C - this energy consumption class assumes a consumption of 1.5 kW;
- D and E - rare values that can be found in older dishwashers, equal to consumption up to 2 kW;
- F and G are energy consumption classes, indicating costs of 2.5 and 2.7 kW, respectively.
When the manufacturer manages to bring the PMM design to a consumption of less than 0.7 kW, a “+” sign is added to the letter A on the marking. Today there are the highest classes: A+ , A++ and A+++. They talk about the significant efficiency of the device - these are the best options on the market.
Energy efficiency classification
Until 2010, the energy efficiency of PMM operation was determined by the level of energy consumption and calculated in units of kW/h. The classification was distributed from A to G. Recently, equipment of classes E, F and G is no longer produced. The energy efficiency of dishwashers is calculated using the EEI (Energy Efficiency Index), which takes into account energy consumption over 280 dishwashing cycles and energy consumption in standby mode. The maximum capacity is also taken into account (measured in cookware sets - from 4 to 17).
Modern and outdated classifications of energy efficiency of dishwashers
The average consumption is taken to be 462 kW/h of electricity per year. An index is calculated for each class relative to this indicator. Today the most economical class is A+++. The value of the EEI index for it is less than 50. The most wasteful energy consumption is observed in class D (EEI index> 90, see table). For PMM, the efficiency level for the process of washing kitchen utensils and drying them is calculated separately.
On each dishwasher you can find a label indicating the energy efficiency class and other basic technical parameters
Unlike advanced models from Bosch, Siemens, Electrolux and other well-known brands, standard PMMs with a small set of programs, smaller capacity and limited functionality consume more electricity, but are cheaper. Therefore, buyers can choose what is more profitable for their budget: buy an inexpensive, but less economical dishwasher, or buy an energy-efficient, but not cheap product.
In order to save energy resources, manufacturers reduce water consumption as much as possible. Modern PMMs consume no more than 7 liters of liquid per cycle of operation with the maximum number of loaded dish sets. Natural condensation drying is becoming more and more advanced, not requiring the expenditure of electricity for the operation of the heating element and fan.
Bosch dishwasher plastic heat exchanger located on the side of the body
Bosch has incorporated built-in heat exchangers into its products that heat the rinse water from the heated liquid used for washing. Due to the heat accumulated in the heat exchanger, dishes dry faster during natural drying. The average power of energy-efficient PMMs during one washing cycle does not exceed 0.5-0.6 kW.
Energy efficiency class of dishwashers
Another value with which the power of a dishwasher is confused is the so-called energy efficiency class, also called energy consumption class.
I think all of you have seen such a sticker on the housings of household appliances (see image below):
It shows a horizontal histogram, such multi-colored bars of different lengths, each of which has a letter marking: A, B, C, etc. Some indicators are also indicated, in particular electrical energy consumption, kW/h per cycle, etc. – but there is no power among them!
A particular energy efficiency class is assigned to a dishwasher based on a comparison of several characteristics, the main ones being the number of dishes loaded and the amount of energy spent on washing. For example, A++ dishwashers consume approximately 0.7 kWh per cycle per cycle, and A+ models consume 0.8 kWh per cycle.
In addition, for different operating modes, different classes can be assigned, for example, in the washing mode - energy efficiency is A, but in the drying mode it is already B.
This information is, of course, important when choosing one model or another, because a more efficient dishwasher will allow you to save on electricity and be more environmentally friendly, but again, this is not power and these concepts should not be confused.
Useful tips for saving energy
If your dishwasher has a delayed start function, use it. Fill the PMM tank with water, then stop the program and program the start at night. Firstly, the water in the housing will warm up to room temperature, and less electricity will be required to heat it. Secondly, electricity tariffs are cheaper at night (provided that a special meter is installed in the apartment or house).
The dishwasher start time is set on the control panel
Do not put dishes covered in old dried dirt into the dishwasher; it is better to rinse them immediately after eating. Otherwise, you will have to run the longest intensive wash program with high water temperature, and it will consume a lot of electricity.
Heavily soiled dishes should be soaked and then washed for a long time and intensively.
So, the choice is yours. Today, dozens of PMM models from renowned manufacturers are presented to customers in the retail chain. All you have to do is choose an economical dishwasher to your liking. You already know how to do this.
