Combine Heat Pumps with Photovoltaics

Why does the combination of heat pump and photovoltaics make sense?

The combination of heat pump and photovoltaic system not only serves for efficient space heating and hot water preparation, but also makes a sustainable contribution to CO₂ reduction and cost savings.

A heat pump largely uses free environmental energy from nature. It requires a small amount of electrical power to operate. The heat pump can be operated with the self-generated electricity from the photovoltaic system. In this way, the consumption of electricity from the grid can be reduced or even avoided entirely. Operation becomes particularly sustainable if the installed photovoltaic system is connected to the heat pump system for control purposes. 

Two important influencing factors in photovoltaics.

The photovoltaic requirement in Baden-Württemberg is groundbreaking for all other federal states. It applies not only to new buildings, but from 2023 also to roof renovations in order to secure environmentally friendly energy. Most other federal states will follow the trailblazer or at least have plans for mandatory solar.

Feed-in Tariff

Every year, many existing photovoltaic systems fall out of the then lucrative EEG feed-in tariff. Many of these Ü-20 systems are small systems on houses, stables or other smaller buildings with an output of up to 10 kilowatts. While the question of self-consumption did not arise in the early 2000s due to the high feed-in tariff and low electricity costs, today it is most economical to use as much electricity as possible from the PV system yourself.

Save electricity with hot water

Our hot water heat pumps from the DHW series

The big advantage of the hot water heat pump is that it achieves high self-consumption values ​​thanks to its low power consumption, even in conjunction with small PV systems.

A hot water heat pump is one of the most efficient solutions for hot water preparation in both new buildings and existing buildings. It can cover the hot water needs of a single-family home all year round, regardless of an existing heating system. 

PV for your own use

Sustainable and independent: Free electricity is generated on the roof from a never-ending source. As soon as the sun shines, the photovoltaic system produces electricity and you can operate your heat pump entirely or partially with your own electricity. So you always benefit when the sun shines. If it doesn't do this, the electricity comes again from the energy supplier. So much for the ideal case. However, the exact opposite often happens: especially on sunny days, the PV system produces a lot of electricity, especially at midday. This is usually the time when you don't need much heat. Then it is an advantage if you operate a heat pump with the electricity you produce yourself and it has an SG Ready function. The heat pump can then produce warm water preferably when green electricity is currently available and store the energy for later consumption.


Advantages. Heat pump and photovoltaics.

Maximizing self-sufficiency.
By combining heat pumps and photovoltaic systems, you can use the solar power generated directly to operate the heat pump. This increases self-sufficiency and reduces energy costs.

Active contribution to climate protection.
The combination of heat pumps and photovoltaics opens up the possibility of generating heat in an environmentally friendly way and thus taking an important step towards reducing CO₂ emissions.

Use excess electricity efficiently.
With a sufficiently dimensioned photovoltaic system, excess electricity can be fed into a buffer or hot water storage tank in the form of heat. This means no renewable energy is lost.

Tips for Implementation.

Pay attention to dimensioning.
Both the heat pump and the photovoltaic system must be appropriately dimensioned and coordinated with one another in order to achieve optimal results. We would be happy to advise you on choosing the heat pump. 

Use intelligent control.
Modern systems offer intelligent control options that optimally coordinate the heat pump's power consumption with the yield from solar radiation. Dimplex heat pumps have the SG Ready label and are therefore able to interact with load-variable tariffs in an intelligent power grid or via control signals in the smart grid.

Store electricity and convert it into warm water.
An efficient heat storage makes it possible to store excess energy in the form of heat and then use it when there is no or too little solar energy available. Our Smart Grid-capable heat pumps can use surplus electricity as heating energy or store it in a buffer or hot water tank for later use.

SG Ready.

Dimplex heat pumps have the SG Ready label.

Intelligent power grids, so-called “smart grids,” are considered an essential prerequisite for the use of renewable electricity. In a smart grid, modern communication technology connects power generators with storage and consumers to ensure the energy supply in a stable power grid. The most important prerequisite for integrating the heat pump into the smart grid is a standardized interface that makes it possible to react to external signals.

Smart Grid-compatible heat pumps are marked with the SG Ready label and can be blocked, for example via a blocking contact, for a maximum of 2 hours if there are load peaks in the network. Conversely, if there is excess electricity in the network, you can use it and store it in the form of hot water, for example. Signal transmitters can be, for example, energy suppliers (EVU). If photovoltaic electricity is to be used in the best possible way as own electricity in the house, the inverter of the PV system can also use the SG Ready functionality. In conjunction with an in-house photovoltaic system, this interface creates the prerequisites for increasing your own consumption.

On average, with a PV system of 6 kWp for a single-family home, you can use around 30% of the electricity you generate for the heat pump. By combining it with additional battery storage, you can even use up to 70% of the electricity you generate yourself, depending on the location and system configuration.

By the way: All Dimplex heating heat pumps have this interface, the SG Ready Label.


The Smart RTC+ intelligent room temperature control system turns the building into an intelligent energy store.

During the heating period, the rooms can be slightly "overheated" with free energy via an intelligent room temperature control (Smart RTC) when there is a solar yield and the building can be used as a heat store. This only happens when energy is available in abundance. The amount by which the rooms can be overheated can be set individually so that less energy is required after sunset.

If there is no PV yield, the desired room temperature is lowered to the minimum comfort level. The reduced system temperature means that the heat pump system runs more efficiently.