What is an electric immersion heater?
An electric immersion heater is a technical component that converts electrical energy into thermal energy. It generally consists of a heating conductor encased in a protective metal tube. As soon as current flows through the heating conductor, it heats up and releases the resulting heat to its surroundings – usually to water in a tank, storage unit, or piping system.
Electric immersion heaters have been used for decades in a wide variety of areas, e.g., in hot water storage tanks, heating systems, or for industrial applications.
They are particularly practical when heat is needed at a specific point or for a limited time, as they generate heat immediately upon being switched on. Especially in connection with photovoltaic systems, they can be used to optimize self-consumption.
In a nutshell: What is novolto’s smart immersion heater?
The smart immersion heater can generate part or all of your hot water using electricity. Using surplus solar power can reduce the electricity you need to buy for water heating. After proper installation, the heater connects using its supplied power cable. Check tank compatibility and follow the installation manual.
Electric immersion heaters have a wide range of applications. They are most commonly found in domestic hot water cylinders or buffer tanks, where they serve as primary or auxiliary heating. In conjunction with a PV system, their use is most economical, as the electricity used usually has very low generation costs. In industry, they are used for heating liquids in tanks or pipelines. Or in aquariums: there, immersion heaters ensure that the water remains at a constant temperature.
What are the advantages of an immersion heater?
This diagram is intended to illustrate the operating principle: The PV electricity* generated with the help of the sun is drawn by the immersion heater via the power socket. The immersion heater is installed in the hot water storage tank and transfers the energy from the electricity to the water as heat. This reduces the operating time of the condensing boiler shown on the right. The boiler normally heats the water by burning gas or oil, which in turn heats the heating water that flows through the heating coils in the hot water storage tank, releasing heat in the process.
* We have omitted the PV panels and inverter so that the image does not become even more cluttered
The combination of an electric immersion heater with a photovoltaic system offers numerous advantages – both ecologically and economically. In times of rising energy prices and increasing demands for climate protection, the use of self-generated solar power is a particularly sustainable solution. Instead of feeding surplus solar power into the public grid – often at comparatively low remuneration rates – it can be usefully employed in one's own home, for example, to heat water for daily needs. This increases the self-consumption rate, which significantly enhances the economic efficiency of the PV system in the long term. Furthermore, the need for fossil fuels such as gas or oil is eliminated, which reduces CO₂ emissions and lowers dependence on energy imports. Also, with regard to the energy transition, the combination of PV and immersion heater is a future-proof investment, as it can be flexibly expanded and integrated into smart energy management systems. For example, in conjunction with battery storage or thermal buffers, self-consumption can be further optimized. The simple technology, low maintenance costs, and long lifespan of the immersion heater make it an attractive addition to any modern photovoltaic system – for more independence, sustainability, and efficiency.
A properly installed and operated immersion heater is generally safe. However, as with all electrical appliances, caution is advised. A reliable overheating protection is particularly important – either in the form of a built-in thermostat or an external controller with a safety cut-off. The immersion heater should only be operated in a liquid medium – so-called dry running can lead to overheating and burnout of the heating element. In addition, a residual current device (RCD) must be present in the circuit to minimise the risk of electric shock. For high-power devices (over 3 kW), suitable fuses and cable cross-sections are also necessary. If the immersion heater is regularly maintained and all safety components are functional, operation is very safe.
An electric immersion heater converts electricity into heat with almost no loss – meaning it has an efficiency of nearly 100%. In most cases, electrical energy is more expensive compared to other energy sources such as gas or oil.
However, using immersion heaters still makes sense if there is an opportunity to purchase electricity at a reduced rate. In combination with a photovoltaic system to optimize self-consumption, an immersion heater can be very efficient, as it utilizes excess electricity that would otherwise be fed into the grid.
This is also possible without your own PV system by using electricity that is exempt from grid fees. You can learn more about this at windduschen.de .
The lifespan of an immersion heater depends on several factors: operating time, water quality, power consumption, and maintenance. Typically, the lifespan ranges from 5 to 10 years. However, in regions with very hard water, it can be significantly shortened if the immersion heater is not regularly descaled. Overloading, for example, due to excessively long operating times without control, can also lead to premature wear. High-quality models with stainless steel casing and good overheating protection usually last longer than simple versions. To maximize lifespan, regular maintenance should be observed, scale-free water preferred or a water softener used, and care taken that the immersion heater is never operated dry.
Using an immersion heater with wind power
Electricity generated from renewable energy sources that we cannot flexibly use or store when it is produced must be curtailed. In 2023, approximately 10 TWh of renewably generated electricity were lost this way, primarily in wind power. At the same time, curtailment costs us billions. Yet, we could put this electricity to very good use – hundreds of thousands of people, for example, could take a warm shower with it every day.
What distinguishes the smart immersion heater?
An immersion heater with an integrated thermostat, multi-stage control, and intelligent regulation offers significant advantages in terms of comfort, efficiency, and safety. While simple models only know "on" or "off," a smart immersion heater allows for precise adjustment of the heating power to the actual heat demand. Specifically, this means the immersion heater only operates when and as strongly as truly necessary. This saves electricity, extends the device's lifespan, and prevents unnecessary heat loss.
An integrated thermostat continuously measures the water temperature in the storage tank and regulates the heating output accordingly. With an adjustable multi-stage control, the user can also determine the maximum power, for example, whether only 800 watts or the full power of 3,000 watts should be used.
This is particularly advantageous if the electricity comes from a PV system whose output fluctuates greatly: With little sun, a low heating level is sufficient; with high output, full power can be used for a short period.
Intelligent control – often via a central energy management system or an app – also allows the immersion heater to be integrated into the daily routine. This means heating can be precisely timed for when the most solar power is available. Novolto's solution, with its intelligent energy management and power tracker, even detects surplus solar power and automatically starts the heating process. The result: maximum self-consumption with minimum effort.
The smart immersion heater also offers advantages in terms of safety. Overheating protection, frost protection, and precise temperature monitoring ensure reliable and low-maintenance operation.
Ultimately, novolto's smart immersion heater offers not only greater efficiency but also more control and future-proofing – making it a reliable choice for anyone who wants to heat intelligently and sustainably.
