Have you ever wondered how much your hot sanitary water costs, or more precisely, the energy for preparing hot sanitary water?


Have you ever wondered how much your hot domestic water costs, or more precisely, the energy required to prepare hot water? Are you a restaurant, bistro, café, laundry, or perhaps a small hotel owner? Do you manage public buildings such as kindergartens and schools? Did you know that you can reduce the costs of hot water preparation by more than 75%?

Imagine a device that can provide you with large quantities of high-temperature hot domestic water (up to 65°C) throughout the year. It enables rapid heating in case of exceptional peak demands. It fully complies with hygiene requirements for drinking water. It can cool and dehumidify your boiler room or any space of your choice. It operates in conjunction with photovoltaic power plants. You can control it with mobile devices from anywhere in the world, and you can check its operation at any time on your mobile device from the moment it starts. A device that allows you to set operating schedules and further optimize desired effects. A device that, along with all the above features, helps you reduce your carbon footprint, with no direct emissions of greenhouse gases or solid particles and becomes even cleaner over time due to the increasing share of renewable energy sources in electrical energy. Now, imagine that this device reduces your hot water preparation costs by 50% to 75%.

All of this is achievable with our KRONOTERM heat pumps for domestic hot water heating.

However, not every heat pump from different manufacturers is suitable for domestic hot water heating, especially for commercial or public use, as most heat pumps cannot heat domestic water to a sufficiently high temperature, or they rely on an electric heater to achieve high temperatures.


The SMAX heat pump, a product of the largest heat pump manufacturer in Slovenia – KRONOTERM, was developed for the above-mentioned goals, which it achieves with excellence. This has been confirmed by independent and accredited institutes WPZ from Switzerland and TÜV Rheinland from Germany. The device is the result of local knowledge, development, and production, and it far exceeds the competition in its class. The SMAX heat pump for heating domestic hot water for larger consumers (WP4 LF-502) achieved the best result among tested domestic hot water heat pumps within its category in March of this year at the Swiss WPZ institute. A COP of 3.85 according to standard EN 16147:2017 (A20/W10-55, XXL profile) and 3.20 according to standard EN 16147:2017 (A7/W10-55, XXL profile) are outstanding results and the icing on the cake for all the other excellent features that this 450 l heat pump for domestic hot water heating possesses.



It is designed for larger consumers as it allows for 576 liters or even 720 liters (when heated to 65°C) of usable hot water (quantity of hot water at 40°C). The thermal power of the heat pump is 4 kW, and the maximum heating power is 8 kW (4 kW + 2 x 2 kW – simultaneous operation of the heat pump and both heaters). It enables both single-phase and three-phase connections (230 V, 50 Hz / 400 V, 50 Hz). The operating range (air inlet temperature) extends from low -7 °C up to +35 °C. It provides both single-phase and three-phase connections (230 V, 50 Hz / 400 V, 50 Hz). Two electric heaters are available for higher water consumption. Depending on the connection of the electrical installation, one (2 kW) or two (2 x 2 kW) heaters can be used. The heaters can be connected in both single-phase and three-phase configurations. As an additional source of heat, various sources that the user already has available (solar collectors or fossil fuel boilers, etc.) can be mounted on the boiler heat exchanger. When using the additional SETSOLAR kit, simultaneous use of two available sources (e.g., an existing boiler and solar collectors) is possible. KRONOTERM sanitary heat pumps allow the cellar or the space where the heat pump is located to be cooled. SMAX is also suitable for this purpose. Depending on the installation, the user can set the spatial arrangement of air intake and/or exhaust.

SMAX is suitable for larger consumers due to its large basic tank (450 liters) and allows the connection of a third additional heater in the lower part of the boiler. This enables additional overheating, whose schedule is set by the user. This is especially important in public institutions, where legionella protection is among the key features. The construction of the tank is designed so that the water is overheated to the set temperature throughout the entire volume, in line with the recommendations of the National Institute of Public Health of the Republic of Slovenia. Overheating the water in the entire volume of the tank can be controlled with an additional temperature sensing probe. The pump also has the option of installing a water temperature sensing probe at the bottom of the boiler using an immersion sleeve and sensor.

In addition to the large quantity of water already heated by the best heat pump in Europe, a demanding user who needs even more hot water can get it. SMAX allows for parallel connection of two, three, or more heat pumps.


One of the important features for the end user when deciding to purchase is also the noise level of the heat pump. The sound power level, which is incidentally the only true and not misleading information about the noise level of heat pumps, is 60 dB(A) at a distance of 1 m (measured according to standard EN 12102:2013) for the SMAX model, which is comparable to the majority of smaller domestic hot water heat pumps whose heating power is only half of the power produced by the SMAX heat pump.

The pump boasts a new graphic controller OPTITRONIC 2, which is also the result of our own knowledge. In addition to efficient management, it allows many useful solutions for the end user (automatic switching between sources (differential thermostat), the possibility of using the pump under a special mode for the use of photovoltaic power plants). In addition to the already mentioned legionella protection function, many others are available – setting operating schedules, different operating profiles: ECO, Normal, and Comfort. It has the “Booster” function, which enables rapid water heating with simultaneous operation of the basic and additional heating sources. All the described options are easily controlled on the heat pump via a color graphical display (LCD), touch-sensitive, or remotely – with the Water.KRONOTERM application – anytime, anywhere, representing one of the key advantages. In addition to user-friendly management, the application also allows for remote service diagnostics.



The family-owned company KRONOTERM (Termo-Tehnika d. o. o.) has reaffirmed, by being recognized for having the best heat pump for the fourth year, that they have a unique, premium product and that continuous investments in their own development and knowledge enhancement more than pay off. Decades of knowledge and experience in the development of heat pumps for preparing hot sanitary water have provided a good foundation for the development of key refrigeration components used in these next-generation pumps. These components serve as the basis for the above-average efficiency achieved by these heat pumps.

Having the best heat pump on the market is undoubtedly a great privilege, but it required tremendous effort to achieve this. The result confirms the effort invested in development in the form of searching for increasingly better and higher-quality solutions, more efficient components, with the idea of making the system as user-friendly as possible for the end-user. Customer experiences and the number of installed devices in homes clearly show that this is a trustworthy product – a premium product.

You can read more about the heat pump HERE.

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