What Is the Fronius Ohmpilot and Can Your Hot Water System Become a Battery?

One of the simplest ways to explain the Ohmpilot is to think of your hot water tank as a form of energy storage.

A thermal battery stores energy in the form of heat rather than electricity. Instead of charging lithium battery cells, excess solar energy is stored as hot water.

This stored heat can then be used later when household members:

• Take showers
• Wash dishes
• Use hot water taps
• Run appliances requiring hot water

In many homes, hot water is one of the largest energy consumers. By using solar energy instead of grid electricity to heat water, homeowners can significantly reduce electricity costs.

Battery storage is an excellent solution, but it is not always necessary for every household. For many homeowners, a thermal battery can provide immediate savings at a much lower upfront cost.

Compared with lithium battery systems, utilising an existing hot water tank can be considerably more affordable. Many households already have the storage component installed.

The Ohmpilot simply helps use that existing asset more intelligently.

Without a battery or energy management system, excess solar generation is often exported. The Ohmpilot can significantly increase self-consumption by using that energy within the home. This becomes increasingly important as feed-in tariffs continue to decline.

Using solar energy to offset water heating costs often provides a faster return than exporting electricity. The more solar energy used within the home, the greater the potential savings.

Hot water can account for a significant portion of household electricity consumption. Depending on household size and existing water heating methods, solar hot water diversion can lead to meaningful savings.

Benefits may include:

• Lower electricity bills
• Reduced grid imports
• Greater solar self-consumption
• Improved solar system economics

The exact savings will depend on:

• Household hot water demand
• Solar system size
• Feed-in tariff rates
• Existing water heating technology

However, for many households, using excess solar to heat water simply makes financial sense.

The Ohmpilot has been designed as part of the broader Fronius energy ecosystem.

When combined with:

• Fronius Smart Meter
• GEN24 Plus inverter
• Fronius Reserva battery
• Wattpilot Flex EV charger

the home energy system becomes increasingly intelligent. The system can make informed decisions regarding where excess solar energy should be directed.

This allows homeowners to build a highly efficient and future-ready energy ecosystem.

Modern homes increasingly have multiple energy demands.

These may include:

• Battery charging
• Electric vehicle charging
• Hot water heating
• Household loads

The Fronius ecosystem allows homeowners to intelligently manage these competing demands. For example, excess solar may first power household loads, then charge a battery, before diverting remaining generation into hot water.

This helps maximise the value of every kilowatt-hour generated.

One of the biggest advantages of the Ohmpilot is that it provides an alternative for households that may not yet be ready for battery storage. Not every home requires a lithium battery immediately.

For some households, improving self-consumption through hot water heating may provide substantial savings at a lower cost.

The Ohmpilot can therefore act as:

• A stepping stone towards greater energy independence
• A complementary technology alongside batteries
• A standalone self-consumption solution

Although hot water is the most common application, the Ohmpilot can also be used for other resistive heating applications.

These may include:

• Electric heating systems
• Buffer tanks
• Pool heating applications
• Space heating solutions

This additional flexibility can further improve solar utilisation.

Australia’s energy landscape is changing. Feed-in tariffs are declining. Electricity prices remain elevated.

Households are increasingly seeking ways to maximise the value of their solar generation. This is making thermal storage increasingly attractive. Because every kilowatt-hour exported for a few cents is a kilowatt-hour that could potentially have been used within the home.

And in many cases, storing that energy as hot water can be one of the simplest and most cost-effective solutions available.

• The Fronius Ohmpilot uses excess solar energy to heat water.
• It effectively turns a hot water system into a thermal battery.
• Dynamic control allows output between 0 and 9 kW.
• It can significantly increase solar self-consumption.
• Thermal storage can provide meaningful electricity bill savings.
• It is an excellent solution for households without batteries.
• The Ohmpilot integrates seamlessly into the broader Fronius ecosystem.
• Sometimes the most cost-effective battery is the hot water tank already sitting in your home.