Water consumption


Although there seems to be a lot of water on Earth, less than one percent of it is available for practical use for human life. The rest is salt water or fresh water frozen in the polar regions, or water that cannot be used for food and other processes. In addition, the population and the demand for fresh water resources are increasing, while the supply remains constant. The fact that although nature takes care of the hydrological cycle, or the continuous circulation of water in the Earth's biosphere, it is not always returned to nature in the same place or in the same quantity and quality should also be taken into account.

One cannot fail to mention the impact of climate change on processes in nature. Naturally, their impact on economic processes is becoming more and more extensive. Long periods of drought have been observed in some regions, which even lead to water shortages. Therefore, it is especially important to take care of the efficient use of water, which goes hand in hand with environmental policy and thoughtful use of energy resources both in households and in office buildings, where energy consumption can be significantly reduced with modern and calculation-based solutions.

Combined water heaters

The combined water heater works using both electricity and heat if it is connected to an existing heating system.

In the warm time of the year, we usually do not use heat energy so widely, so the operation of the boiler can be ensured using electricity. In winter, or when the central heating works, its heated water flows through the coil in the boiler, which also ensures water heating in the boiler. On the other hand, when the heating does not work, the electric heating element starts working, which ensures the heating of water inside the boiler. To prevent water from returning to the pipeline, a safety valve or non-return valve is installed on the boiler.

If necessary, you can choose the most appropriate type of energy, thus significantly reducing electricity costs.

Differences between volumetric and instantaneous water heaters

Volumetric water heater or boiler

  • The electrical power of the boiler is not high, no more than 2 kilowatts (kW). During the heating process, the entire amount of water in the boiler heats up to the required temperature, and then it remains hot in a thermos-type tank.
  • It is recommended to choose the volume of the boiler depending on the number of people who use it, as well as the water usage habits.
  • Likewise, a boiler should be chosen with a thicker tank wall – the thicker it is, the better thermal insulation and less heat loss. It is recommended to choose a water heater with an eco-function, which allows you to maintain a minimum water temperature even when hot water is not being consumed.
  • It should be taken into account that, for example, the boiler will require additional space, which could be an important aspect if the room is small. The boiler's electricity consumption depends to a large extent on both the set water heating temperature and the volume of the tank.
  • When researching the selection of electric water heaters, you should pay attention to the energy efficiency class – the higher it is, the less electricity the water heater will consume.

Energy Labels


  1. Manufacturer and model
  2. Water heating function that includes the declared load profile of the hot water boiler
  3. Energy efficiency class
  4. Noise level, in decibels
  5. Projected power consumption, kWh/year
  6. Projected fuel consumption, GJ/year
  • The energy label is awarded to a hot water boiler that uses a fossil or biomass fuel, or an electric heating element, such as a hot water boiler.
  • The declared load profile of the water heater indicates the load profile at which the energy efficiency class (from 3XS to XXL) has been specified by the manufacturer. It includes the frequency and quantity of daily water consumption, water temperature and other parameters.
  • 3XS and XXS water heaters are suitable for small offices or hand washing. XS and S heaters will be useful for larger offices or for washing dishes and hands. M–XXL heaters are suitable for household needs. The higher the load profile, the more suitable the heater is for households with a larger number of occupants.



Low electrical power, 2 kW on average

Water pressure is not essential

Heat loss because the water is kept hot continuously

Larger size

Longer water heating time (1–8 h depending on volume)

Regular maintenance is required

Use of a water volume heater:

  • The water heater should be placed as close as possible to the place of water use.
  • The water heating temperature should be set between +55 °C and +59 °C. Exceeding this temperature, limestone begins to be released more actively, thus the heating element of the water heater becomes limescale faster and its electricity consumption increases.
  • At least once a year, the water heater must be serviced, during which the heating element is cleaned, the inside of the heater is thoroughly rinsed, and the condition of the anode is assessed. If the anode is broken, it must be replaced. Otherwise, the heating element will scale faster, increasing the water heater's electricity consumption.
  • Before cleaning, the volume water heater must be disconnected from the electricity and water supply. It is preferable to entrust the maintenance of the water heater to a specialist.
  • In order to keep the water hot all the time, the boiler periodically consumes electricity during the day. In standby mode, it can consume 1 kWh of electricity per 24 hours. It is recommended to turn off the boiler on holidays.

Instantaneous water heater

  • Due to the compact size of the heater, the device can be easily hidden in an interior. The water is heated instantly – when you open the water faucet, hot water flows immediately. There is no heat loss, because the water is not continuously kept hot in the tank, as it is in a boiler.
  • So, this water heater is more efficient than the boiler, but it has a limitation – the high electric power. Therefore, a three-phase electricity connection and the current size of the input protection device should be at least 25 amperes (A). It is usually not possible to install it in places where there is only a single-phase connection.



There is no heat loss, because the water is heated only at the moment it is used

Instantly warms the water flowing through it

Compact size

An unlimited amount of water can be heated

High electrical power, 15 kW on average

A three-phase connection and an input protection device current of at least 25 A are required

The required water pressure is at least 2.5 atmospheres

  • In order not to waste electricity unnecessarily, it is recommended to choose a flow-through water heater of appropriate capacity, but also make sure that the capacity is not too small, and that the heater is able to provide hot water at all water intake points. For example, in the water supply system, the cold water temperature is 10 degrees, we want to heat it to 40 degrees, so the temperature difference is 30 degrees. We also want the water flow to be large enough – 10 litres per minute. So we have a suitable instantaneous water heater with a capacity of 21 kW.


  • Water heating (if used) is a significant source of office costs. It usually accounts for about 7% to 12% of electricity costs.

There are four ways to reduce water heating costs

  1. Use less hot water.
  2. Reduce the temperature of the water heater thermostat.
  3. Insulate the volumetric water heater or boiler.
  4. Get a new, more efficient heater model, such as a tankless heater.


Hot water preparation

Solar energy can be converted into thermal energy using a solar collector.

The device captures solar radiation and converts it into thermal energy. This heat energy can be used to prepare hot water or as additional heat energy in heating systems. The benefit – up to 70% lower expenses for water heating.

The system is roughly as follows: solar collector panels are installed on the roof of the building or in some other sunny place, in which the heat carrier (special liquid) heats up, which in turn gives off heat in the heat exchanger, for example to water to be heated or to the heat carrier of the heating system.

There are two types of solar collectors: flat solar collectors and vacuum collectors. The main difference is their efficiency and the type of thermal insulation used – mineral wool is used in flat collectors, and vacuum in vacuum tube collectors. Flat solar collectors are considered the most suitable for the conditions of Latvia.

Similar to solar cells, collectors also work most efficiently when they are installed facing south.

Using a solar collector system, for example, hot water supply will reach 99% in summer, but only 10–15% in winter.

Choosing a heat accumulator with an electric heating element will give you the opportunity to provide hot water in cloudy and cool weather. The solar collector must provide no more than 70% of the heat energy required for hot water per year.

Good to know! Unlike solar panels, when installing a solar collector, coordination with the responsible authorities is not necessary. The installation is similar to, for example, an air conditioner.

The story of the experience of the Mārupe Municipality Council

Taking care of plumbing

In addition to the use of technology, we first want to emphasise that in plumbing, it is especially important to carefully monitor the state of the building's internal engineering communications and equipment, to perform an assessment, preventing damage to dripping water faucets, shower equipment or toilet bowls, replacing them if necessary. Damaged water taps and water flushing boxes in utility rooms can imperceptibly cause significant water losses – if it is assumed that one drop flows from the tap per second, up to 90 l of water will be unnecessarily wasted per month due to a dripping tap.

In this section, you will find information on how to use water resources in an energy-efficient way, recommendations for choosing plumbing fixtures, as well as advice on what changes and additions you can make to achieve significant savings in the use of resources in the future.

Possibilities for reducing water consumption


If you need to buy a new water faucet, choose an energy-efficient faucet with reduced eco flow. Modern faucets incorporate various mechanisms reducing water consumption, for example, the hot water saving function – the handle always returns to the default position, so that when you open the water supply, lukewarm (or completely cold) water flows initially, and not immediately hot, thus preventing consumption additional energy from increased water temperature when the water supply is reopened.

Water saving function – by locking the handle in a specific maximum position, it is also possible to set the maximum water flow per minute that flows through the faucet, etc.

Energy-efficient faucets can use as little as 5 litres per minute, while a standard faucet's flow rate averages 10–12 litres per minute. There are also water faucets with an eco-button, which, depending on the faucet model, reduces the water flow by 10–40%.

Thermostatic faucets are also available, which help obtain the required water temperature immediately, without wasting water unnecessarily – despite the fluctuations in the temperature of the incoming cold and hot water, a constant water temperature is always maintained. Thus, it is possible to set 17 °C instead of the standard 22–24 °C.

For some time now, various models of non-contact faucets have been available on the market, which were developed by sanitary ware manufacturers, following the development of technology and world trends. These faucets work with the help of built-in sensors – to start the water flow, you only need to bring your hands closer to the spout of the faucet. As soon as your hands are moved away, the water supply is automatically cut off, so you will never forget to turn off the water. These faucets meet strict hygiene requirements, which are especially important in the public sector.

Certain faucet models can be connected with the Bluetooth function, and using the manufacturer's app, it is possible to easily adjust and maintain faucet settings, and monitor water consumption as well as battery life.

It is also possible to improve an already installed water faucet by adding a special nozzle – an aerator. How does it work? When water flows at a certain speed along small openings in the system, a suction force is formed, which adds air to the water, creating a strong, bubbling jet of water. Thus, it is possible to reduce water consumption by up to 50%, respectively. Without the aerator, the water consumption is on average 10 to 12 litres per minute, and with the aerator – 5 to 6 litres per minute.

Currently, in more and more faucets, the aerator is built into the standard mechanism. You can see this by the water jet – if the water does not flow like a transparent stream, but frothy and bubbling, the faucet has an aerator function.

Toilet bowls

Most businesses (apart from the manufacturing sector) have similar water usage patterns to domestic environments, with large amounts of water consumed in shared bathrooms, toilets, hand washing, cleaning, and toilet flush boxes.

It is recommended to choose a toilet bowl with two water flushing modes or two water flushing buttons – one of them usually consumes twice as much water, so use it as needed without pressing the big button.

You can also install a special dispenser in the toilet flush box to reduce the amount of water used each time you flush. The water level can be adjusted, for example, from 10 to 5 litres.

Additionally, in care of the environment, we invite you to review the habits of toilet cleaners, switching to more environmentally friendly solutions. It is important to note that strong chemical cleaning agents destroy not only the bacteria in the toilet bowl, but also the good bacteria in the sewage treatment plant.


If the bathroom at the workplace is equipped with a shower, it is recommended to buy a shower head with a water flow reducer, as well as to use a faucet with a built-in aerator in the shower, because such a head sucks in three litres of air for one litre of water, creating massaging water jets and allowing easy rinsing. Using a standard shower faucet, 15–20 litres of water can flow out per minute, while an efficient shower faucet may only drain 8 litres per minute.

Water losses occur while the user adjusts the desired temperature, therefore, when purchasing a new water faucet, it is recommended to choose a faucet with a thermostat that allows you to set the desired water temperature and maintain it throughout the wash.

  • Always close the taps and the shower tightly (you can also use sensor settings in the faucet here). A dripping tap can waste up to 90 litres of water per day.
  • Reduce shower time and save up to 20 litres (using a standard shower faucet) of water per minute.

In addition to choosing appropriate, efficient plumbing fixtures and changing habits, we recommend that you consider using smart technology in your offices and common areas.

Manufacturers offer to equip water supply equipment with water leak detectors, which will shut down the system upon detection of damage or leakage, as well as send a message to your smartphone with the help of an app. These detectors also measure the level of humidity in the set area, thereby ensuring not only the safety of your building, but also the microclimate in it.


Business experience

Hansgrohe - technologies for saving and sustainable use of water resources

Villeroy & Boch Gustavsberg - energy saving and smart symbols

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