The number of heat pumps in the Netherlands is rapidly increasing, especially as more homes are built without a gas connection. To provide hot water in gas-free homes, solutions include district heating (where available) or using a heat pump.

Big consumers of energy

Heat pumps use electricity to heat water, similar to electric boilers. However, heat pumps are far more efficient because they harness the energy from the outside air. As a result, a heat pump can generate 3 to 5 times more heat per unit of electricity than an electric boiler. Despite their efficiency, they remain high-energy consumers—after all, we need a lot of hot water in our homes.

The electricity needed for a heat pump comes either from the grid or from solar panels on the roof. With the gradual reduction of net metering incentives, it becomes increasingly beneficial to prioritize using your own solar power over feeding it back into the grid. There are two ways to achieve this.

Two Ways to Optimize Heat Pump Usage

The first method (which we’ve discussed before) is direct control via a smart home energy manager, such as the Sunny Home Manager. In this setup, the heat pump is directly connected to the home energy manager, allowing precise control to maximize the use of solar power. However, this currently works only with a few heat pump brands, such as Stiebel Eltron and Vaillant.

The second, more widely available and simpler method is using a ‘Smart Grid Ready’ (SG-ready) heat pump. A heat pump with this feature has a basic on/off switch that can signal the device to increase or decrease power consumption based on availability.

How Does ‘Smart Grid Ready’ Work in Practice?

Consider this example: A heat pump typically maintains a buffer tank of heated water at 50°C. When the water temperature drops below this level, the heat pump activates, and once the target temperature is reached, it turns off. However, when the SG-ready function is activated, the heat pump allows the buffer tank to heat up further, for example to 60°C. This extra 10°C effectively stores surplus solar energy in the form of heat.

The SG-ready function is only activated when there is a specific reason—such as a favorable electricity price (e.g., night tariff) or a surplus of solar power that isn’t needed elsewhere in the home. To enable this, a smart energy manager detects the right moment to switch on the SG-ready mode.

The Sunny Home Manager, for example, can control an SG-ready heat pump using controllable relays from Shelly. The relay switch activates the SG-ready function when the Sunny Home Manager gives it a signal. When the Sunny Home Manager decides the function is no longer needed, it tells the relay to open again, disabling the SG-ready mode (while the heat pump itself continues operating normally).

Limitations of Smart Grid Ready

This system works well but has one drawback: The Sunny Home Manager can switch the SG-ready function on and off but cannot measure the exact additional power consumption of the heat pump. While it registers that more solar power is being used in the home, it cannot determine how much of that energy is specifically used for heating the buffer tank. As a result, it cannot optimize power consumption with the same precision as when directly communicating with a heat pump. What we can do however, is add a smart plug to measure the power consumption of the heat pump and display it in the SMA Energy app. That way you can see how much of the required energy is provided by the solar panels, and how much comes from the grid.

Conclusion

Between the two methods of integrating heat pumps with the Sunny Home Manager, the first option (direct communication, available only with select brands) is the most efficient. However, the SG-ready approach is still a great alternative for homeowners looking to increase their self-consumption of solar energy.

Want to learn more? Feel free to email service@zonnefabriek.nl, and we’d be happy to explain!