ANTIK Photovoltaic water heating for apartment buildings
Inverter AC input: 230 VAC, max. 6A
DC input of the inverter: 3× 0 – 400 VDC, max. 16A
AC inverter outputs: 0 – 250 VAC 50 Hz
rectangular waveform (modified sine wave) suitable only for resistive loads
MPPT inverter: Maximum power 3×3000W
User interface: 2.5” OLED display, touch buttons
Communication interfaces: Wi-Fi – connection to ANTIK SmartHome
Mounting method: Wall mounting using the included bracket
Dimensions: 480 × 160 × 80 mm
Weight: 4 kg
Operating temperature: -20 to 60 °C
Protection: IP31
A more powerful version of the domestic 3 kW heater, intended primarily for use in larger buildings for the preparation of hot water (DHW) . The unit is designed to connect a 9 kW heating element (3× 3 kW). The unit can operate independently or as a system of multiple units together with the ANTIK control and communication module, which ensures the functioning of the system as a technological unit together with valve control, water meter reading and circulation pump drive.
ANTIK 9 KW Photovoltaic water heating for apartment buildings
A high-performance and scalable solution for preparing domestic hot water in multi-apartment buildings using solar energy. The system uses 9 kW inverters with MPPT technology , which convert DC voltage from photovoltaic panels to AC output directly to storage tanks .
Features:
- 9 kW power unit (3x 3 kW outputs) - Designed for direct heating using three AC output branches with a power of 3,000 W.
- DC input voltage up to 400 VDC - Compatible with PV strings 6× 550 W, output voltage optimized at 300 VDC/39 A for maximum power without losses.
- Built-in MPPT controller (3x) - Each output is independently controlled by its own MPPT algorithm.
- Modified sine wave output (230 VAC/50 Hz) - Safe power supply for resistance heaters with low harmonic interference.
- RS485 and Wi-Fi communication interface - Connection with the ANTIK SmartHome control center, remote monitoring, OTA updates and diagnostics.
Additional features:
✅ Remote system monitoring - Control of power, temperature and water consumption via the ANTIK SmartHome application or central control unit.
✅ Integration with sensors and valves - Possibility of controlling circulation pumps, electromagnetic valves and reading data from water meters.
Automation and programmable parameters
The ANTIK Smart DC–AC inverter system for apartment buildings enables intelligent and flexible control of water heating based on current operating and environmental conditions. Using the Antik SmartHome application, you can create advanced automation scenarios that optimize the use of photovoltaic surpluses and reduce operating costs.
Examples of automations:
- Water heating is activated only if the system detects excess energy and the export to the grid exceeds 300 W.
- Heating is automatically deactivated after 18:00 if the desired water temperature has been reached during the day.
- Once the battery storage is fully charged, the system automatically switches to water heating.
- The heating output is adjusted in real time according to the current sun intensity or weather forecast.
Coverage and return on investment in residential solutions
How much water can the system heat?
The ATK-PWH9KW system with a maximum output of 9 kW (3 × 3 kW) can heat approximately 500–1000 liters of water per day, which normally corresponds to the consumption for 4 to 8 apartments, depending on the number of people and their habits.
How many units are installed in apartment buildings?
In practice , 2 to 4 units are most often installed in apartment buildings, which can effectively cover 12 to 30 residential units . The solution is flexible and scalable according to the size of the building and storage tanks.
Solar surplus utilization and return
In combination with rooftop photovoltaics with an output of 8–12 kWp, 60–80% of daily water heating can be covered solely from solar surpluses.
Boiler as an alternative to battery storage
When considering how to efficiently harness solar energy, battery storage is often the first choice. Although it is an advanced solution, its purchase price, technical complexity, and maintenance requirements can sometimes be a barrier.
A simple and proven alternative is to use an existing boiler as an energy storage device – not in the form of electricity, but in the form of heat.
How it works:
In practice, this means that solar radiation is converted into direct current by photovoltaic panels, which is then fed directly to the boiler's heating coil via a DC converter. The electricity is immediately converted into heat - without passing through a mains converter, without feedback to the distribution network and without unnecessary conversions.
As a result, the water in the boiler is heated continuously during the day, while the sun is shining - without the need for intervention from the network. The heat remains safely "stored" in the tank and is available whenever households need it. This makes it possible to cover hot water consumption even in the evening or during inclement weather.
Modular system architecture
The ANTIK Photovoltaic water heating system for apartment buildings operates on the principle of modular connection of power converters , which convert DC voltage from photovoltaic panels to AC output intended for direct power supply of heating elements in storage tanks.
In case of a requirement for a higher thermal output than 9 kW, it is possible to combine multiple inverters (each with an output of 9 kW) , thus linearly adding up the system output. The inverters cooperate via a central control and communication unit , which:
- Controls individual inverter outputs according to current operating conditions (voltage, surplus, water temperature),
- It controls servo valves and circulation pumps based on data from temperature sensors at various points in the system,
- Provides data collection and remote monitoring via the ANTIK SmartHome server,
- Allows reading data from water meters and other sensors (e.g. for consumption analysis).
Continuous power regulation according to the currently available solar energy
Unlike conventional solutions that require an inverter and complex energy conversion , this system allows for direct power supply of resistive loads (e.g. heating elements in a boiler) from the DC output of solar panels via a power unit.
This minimizes energy losses , eliminates the need for battery or AC storage, and maximizes the use of available solar radiation in real time .
This technical solution delivers higher efficiency, lower investment costs and faster return on investment – without compromising on reliability or performance.
Intelligent power control based on the real availability of solar energy at a given moment
The ANTIK system does not only work based on a fixed output - it constantly monitors the current voltage from the PV array, surplus flow, water temperature and system status . Thanks to the integrated MPPT algorithm and the possibility of automation via ANTIK SmartHome, the system dynamically regulates the heating output to use the maximum available solar gain without overloading the boiler or other components.
- Adaptive power control – the system continuously monitors available DC voltage, temperatures and surplus flow from photovoltaics
- Dynamic heating optimization – the inverter automatically adapts the power to current conditions (e.g. changes in cloud cover or seasonal fluctuations)
- Maximum use of solar energy – without unnecessary losses or overloading the spiral, even in variable conditions
- Extending system life – thanks to smooth power startup and protection of components from thermal and electrical stress.
🌥 What if the sun doesn't shine?
The system is designed to ensure the required comfort even during periods of low solar energy availability . In case of insufficient photovoltaic power, it is possible to automatically switch water heating to mains power or another available energy source. Thanks to intelligent control and programmable rules, the system adapts to current conditions and ensures water heating without interruptions .
Technical overview of the installation
Installing photovoltaic water heating requires a comprehensive approach including the connection of photovoltaic panels, a 9 kW DC/AC inverter, a storage tank and peripheral devices (sensors, valves, pumps). For more information, see the Frequently Asked Questions for Technicians (FAQ) section.
Multi-column
🔧 More demanding steps in terms of professional skills
- Heating element sizing and power load calculation.
- Cabling of DC branches and selection of the correct cross-section according to line length and power.
- Control of multiple units in one system (e.g. apartment building).
- Configuration of system logic (times, backup modes, water disinfection, etc.).
🧱 Common steps that even an experienced user can handle
- Connecting the unit output to a standard electric heating element.
- Positioning and orienting the panels using available support systems.
- Pairing the system with the application via QR code and intuitive interface.
Download the ANTIK SmartHome® app
Photovoltaic water heating for apartment buildings from ANTIK is fully controllable via the ANTIK SmartHome® application, which allows you to comprehensively manage the device and optimize operation in real time - directly from your phone.
In the app you can:
- Monitor system performance – voltage, current, power from PV panels and inverter operation.
- Set target water temperatures – separately for solar heating and backup modes.
- Optimize energy distribution – management based on surpluses or night-time tariffs.
- Schedule heating – define precise intervals for on/off according to your needs.
- Analyze data – daily and monthly consumption, temperature and operation statistics.
- Activate hygiene cycles – automatic disinfection of the tank at the selected temperature.
- Configure communication with the system – support for Modbus protocols, integration with the central unit.
💬 Expert advises: ATK-PWH9KW
💡 The ATK-PWH9KW device is a reliable solution for smart water heating in apartment buildings with photovoltaics. In technical rooms or boiler rooms where common storage tanks are available, this powerful unit (3×3 kW AC) can effectively utilize solar surpluses without the need for batteries.
In Slovak conditions, with a rooftop PV installation with an output of 8–10 kWp, a surplus of up to 12–15 kWh per day is generated on sunny days , which corresponds to heating water for 3–6 apartments. The system also allows the control of radiators, valves and pumps and is compatible with intelligent control via ANTIK SmartHome.
Compared to battery storage (€4,000–€6,000), this unit, priced from €799, represents an affordable and maintenance-free alternative that will ensure a return on investment within 2–3 years – especially where solar surpluses would otherwise remain unused.
— Ing. Radoslav Lukáč, specialist in energy efficiency and solar solutions
FAQ – For users
What type of boiler do I need?
The system is compatible with common electric storage water heaters with a standard heating coil (230 V or 3× 230 V). For optimal performance, we recommend coils with a power of 3 to 9 kW. If necessary, the heating unit can be easily replaced without having to change the entire water heater.
How many apartments can the unit serve and how much water can it heat?
The ATK-PWH9KW unit with an output of 3×3 kW is designed for central hot water supply in apartment buildings or larger buildings. With a properly sized storage tank (e.g. 500–1000 l), it can heat up to 400–800 liters of water per day, which corresponds to the DHW consumption of 4 to 8 apartments (with a typical consumption of 50–100 l/person/day).
The efficiency of the system depends on the power of the connected photovoltaics, the type of heating element and the system configuration. Under optimal conditions (e.g. 8–10 kWp PV system and correctly set heating logic), it is possible to cover more than 60% of the daily hot water consumption on sunny days from solar surpluses alone , without the need for batteries or connection to external heating sources.
How many units are typically installed in apartment buildings?
In apartment buildings , 2 to 4 ATK-PWH9KW units are typically installed , depending on the size of the building, the number of apartments and the hot water volume requirements. Each unit can independently serve a storage tank with a capacity of 500–1000 l and cover the DHW for approximately 4 to 8 apartments .
Multiple units can be connected into a common system with central control via the ANTIK module , which ensures simultaneous control of valves, pumps and optimization of the use of solar surpluses across the entire building. Such a modular approach allows for easy scaling even for larger apartment buildings or building technical facilities.
Is it suitable to use the system in larger residential buildings?
Significant reduction in operating costs. Water heating occurs when solar energy is available – without the need to purchase electricity from the grid. In addition, the system is maintenance-free and has no mechanical parts subject to wear.
Does it also work in apartments or older buildings?
The system is also designed for smaller buildings, apartment units or older installations - precisely because of the low electrical installation requirements. In the case of multi-apartment buildings, it is also possible to deploy a central module with multiple outputs and priority control .
FAQ – For Technicians
Is it necessary to modify the main switchboard?
No. Thanks to the plug-and-play solution, there is no need to install separate circuit breakers or contactors. The device plugs into a classic 230 V socket and communicates with the boiler's heating element.
What is the configuration of the power outputs?
The system is designed for 3-phase heating (9 kW), with each phase controlled separately according to the available power from the PV panels. Operation in a single-phase version (3 kW) is also possible.
Is it possible to chain or expand the system?
Yes. The solution supports parallel operation of multiple units. With proper configuration, the system can also be deployed in apartment buildings or multifunctional buildings.
How is backup heating outside of surpluses handled?
The system allows you to define the temperature regime at which the backup AC heating is activated (e.g. during the night). The user can limit the heating time or the performance ceiling, thus optimizing the consumption from the distribution network.
Does the device require active cooling or special placement?
No, the unit is equipped with a passive cooling system with effective heat dissipation through the aluminum housing. Just ensure enough space for natural ventilation - e.g. do not place in closed cabinets without air flow.
