How does the use of heat pumps influence climate change?

To effectively combat climate change, a significant reduction in CO2 emissions is necessary. As part of the “European Green Deal”, the EU Commission has tightened its targets and is now aiming to reduce emissions by 55% by 2030 (previously only 40%). However, studies for Germany show that a 65% reduction in greenhouse gas emissions by 2030 is necessary to achieve climate neutrality by 2050. Germany must therefore do even more to achieve the goals. This is where it is important to switch the heat supply in buildings to low-CO2 or climate-neutral technologies, as this conversion represents a key area in the fight against emissions.

The energy efficiency of heat pumps can significantly contribute to reducing CO₂ emissions. They are thus making a significant contribution to the energy revolution. But are heat pumps really the key technology for climate protection?

Heat pumps are a key technology for effectively using renewable energy to supply heat

Since space heating accounts for around 70% of an average household's energy consumption, CO2 reduction through heat pumps will play an important role in minimizing emissions in Germany. Germany cannot achieve its climate goals without a renewable heat supply, and heat pumps are essential for this.

In almost all scenarios for future energy supply, heat pumps are regarded as the central heating technology. This is primarily due to their high efficiency. A heat pump obtains around three quarters of the required energy free of charge from the environment by taking natural heat from air, water or the ground. This is a significant advantage over traditional heating systems. When heat pumps are powered by renewable electricity, the result is a completely climate-friendly heating solution without harmful CO2 emissions. Despite these undeniable advantages, the use of heat pumps in Germany is unfortunately still limited (5.8 heat pumps per 1000 households). Compared to other European countries, Germany is at the bottom. The Nordic countries Finland, Norway, Sweden and Denmark installed the largest proportion of heat pumps in 2022. Finland is the leader with sales of 69.4 heat pumps per 1,000 households in 2022. In Norway, the comparative figure is 59.9, in Sweden it is 39.3, in Estonia 32 and in Denmark just under 30 heat pumps per 1,000 households. For Germany, the goal must therefore be to further promote the spread of such technologies, such as heat pumps, and to provide consumers with more information and then also to support them in replacing heating systems.

This is where heat pumps come in. They represent the key technology for the future, as they draw a large proportion of the required energy from the environment. This is done with remarkably high performance coefficients (COP values), which quantify the efficiency of heat pumps. The COP indicates how much heating energy a heat pump supplies in relation to the drive energy used. On average, modern heat pumps can achieve COP values of between 3 and 5, which means that 3 to 5 units of heating energy are provided for every unit of electrical energy consumed.

The efficiency of a heat pump depends heavily on the heat source used:

• air to water heat pumps are widely used and draw heat from outside air. They are particularly flexible to install, but can be less efficient when outside temperatures are very low.
• water to water heat pumps use groundwater as a heat source, which has a relatively constant temperature. These systems typically offer higher COP levels but require access to an appropriate aquifer.
• geothermal heat pumps (also known as brine-water heat pumps) obtain their energy from the ground by using the solar energy stored in the ground. They require the installation of geothermal probes or area collectors and offer high efficiency throughout the year thanks to the stable temperature in the ground.

Compared to conventional heating systems that use fossil fuels such as gas or oil, heat pumps can reduce a household's CO2 emissions by up to 70% when powered by electricity from renewable sources. This drastic reduction in greenhouse gas emissions makes heat pumps a key technology for achieving climate goals.

The function of a heat pump is in principle similar to that of a refrigerator, only in reverse form and significantly more powerful. While a refrigerator removes heat from the interior, the heat pump extracts energy from an external heat source and transfers it to a building's heating system.

A heat pump is an attractive option not only for those who are environmentally conscious and want to make a contribution to protecting our planet, but also for those who want to keep an eye on their costs and operate efficiently. Thanks to its high energy efficiency, a heat pump can significantly reduce heating costs. This represents a direct financial benefit and can result in significant savings over the life of the device. Installing a heat pump also has the additional advantage that it can increase the value of a property. This can be particularly attractive if you're considering selling your home in the future. Heat pumps are also future-proof, as they already meet the energy requirements for new and old buildings. They are therefore a good investment in the future, as they can help keep your house up to date in terms of energy efficiency in the coming years.

How does a heat pump work?

Heat pumps are a sustainable technology that uses the energy available in the environment (from air, water, or soil) to heat buildings. The basic working process of a heat pump, the so-called refrigeration cycle process, consists of four main steps: evaporation, Compression, condensation and expansion.

Evaporate: The process starts with the transfer of ambient heat to a special refrigerant. This special refrigerant has the unique property of turning into a gaseous state even at relatively low temperatures. This evaporation process, which converts the liquid into a gas, is the first step in the process.

Densify: After the refrigerant has evaporated, it is compressed in an electrically driven compressor. As a result of this compression process, the temperature of the gas rises significantly.

condense: The next step is condensing. Here, the increased heat of the gas is transferred to the building's heat distribution system. During this process, the refrigerant changes from a gaseous state back to a liquid state, which is known as condensation. During this condensation, the refrigerant cools down again.

relax: In the last step of the process, the pressure of the refrigerant, which is now liquid again, is reduced by an expansion valve. This expansion causes the refrigerant to return to the liquid state and the entire process can start all over again. This cycle is repeated continuously, which enables the efficient generation and distribution of heat.

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Key figures to describe energy efficiency

The efficiency of a heat pump is usually defined by the COP (Coefficient of Performance) or the annual performance factor (JAZ). Both key figures describe the ratio of energy used to heat obtained.

Die Coefficient of performance (COP) represents the ratio of the heat output to the absorbed electrical power. If the efficiency factor is high, it means that the heat pump is highly efficient and requires less electrical energy to generate a certain heat output.

Die Annual performance figure (JAZ) is another important key figure. It shows the ratio of the heat generated over the course of a year to the electrical energy absorbed. It takes into account both the heating output of the heat pump and its electricity consumption over the entire year. In this way, it provides a good clue as to how efficiently the heat pump is working on an annual average. Calculating the JAZ of a heat pump is important when considering efficiency.

Die seasonal performance factor (SCOP) is a concept that is similar to JAZ but goes one step further. It also takes into account seasonal fluctuations in the efficiency of the heat pump. It indicates how efficiently a heat pump operates over the entire heating season, i.e. taking into account colder and warmer periods.

However, the efficiency of a heat pump depends on numerous factors. This includes the type of heat source, the technology used and the energy status of the building to be heated. Heat pumps equipped with inverter technology are particularly efficient. They dynamically adjust their output to the building's current heat demand. This not only increases their efficiency but also extends their lifespan. Another important aspect is the choice of refrigerant. This should ideally have a low GWP (Global Warming Potential) in order to maximize the environmental compatibility of the heat pump.

You can find out which types of heat pumps are there in our article on Types and operating modes of heat pumps - This is how heat pumps work.

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Environmental impact of renewable heating systems

The environmental compatibility of heat pumps depends on various factors that go beyond pure technology. The production methods, energy consumption during operation, the source of electricity for the heat pump, maintenance practices, the type of refrigerant and the recyclability of the heat pumps at the end of their service life are decisive. All of these factors must be optimally adjusted to make the heat pump as efficient as possible. In order to maximize their efficiency and benefits, a correct and professional installation is also necessary. Only when heat pumps are installed by qualified specialists can they develop their full potential and strengthen their role as a sustainable solution for heating. This underlines the importance of taking a holistic view of heat pumps that goes beyond mere purchase and installation and covers the entire lifespan and associated practices.

Since we have to deal with a shortage of skilled workers in Germany, it cannot be assumed that many new qualified specialists will help install more heat pumps in Europe by 2030. As we know, it is nevertheless of paramount importance that qualified specialists carry out the installation to ensure the optimal performance and sustainability of these advanced heating systems. Autarc has set itself the task of fighting this problem and improving the planning and installation of a heat pump. Find out more here: About autarc.

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The role of renewable energy and power sources

In many parts of the world, fossil fuels such as gas, coal and crude oil are used to produce heat and electricity. However, renewable energies are increasingly replacing them and reducing emissions of climate-damaging gases. This makes them an important factor in the fight against climate change. The German Federal Environment Agency has calculated the impact of renewable energy on combating climate change. In 2022, for example, emissions of 237 million tons of CO₂ equivalents could be avoided in Germany, and that only by using renewable energy.

The importance of renewable energy was once again emphasized at the COP28 climate conference in Dubai in December 2023. At this conference, an agreement was reached for the first time worldwide to move away from fossil fuels. In addition, renewable energy sources worldwide are to be tripled by 2030. In addition, 792 million US dollars have been set for those affected by climate damage. A decisive moment in global climate policy.

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Influence of the power source on the CO2 balance

Germany must meet the goals set by the 2023 climate conference. For this, it is important to investigate how this can best be achieved and which sources have the greatest influence on our CO2 balance.

As in recent years, the energy industry accounted for the largest share of carbon dioxide emissions in 2022, at 37.0%. Around 247 million tons of carbon dioxide were released from this sector in 2022. The categories households/small consumers (17.3%), road traffic/other transport (22.1%) and manufacturing/industrial processes (together 22.8%) are currently slightly less important in terms of carbon dioxide emissions.

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How much CO2 does a kilowatt hour of electricity generate in the German energy mix?

The indicator “direct CO₂ emissions per kilowatt hour of electricity”, also known as the “emission factor” or specific emission, characterizes how climate-friendly electricity generation is. In Germany, generating one kilowatt hour of electricity resulted in an average of 434 grams of CO₂ in 2023. In 2021, this figure was 410 grams per kilowatt hour and in 2020 369 grams per kilowatt hour. The specific greenhouse gas emissions, converted into CO₂ equivalents, amounted to 750 g/kWh for 2022. The decline in specific greenhouse gas emissions in 2020 is due to the increased share of renewable energy in the electricity mix, the lower share of electricity generation from coal and the increased share of electricity generation from natural gas, which has a lower emission factor than coal. The downward trend up to 2020 was reinforced by the corona pandemic and the associated reduction in electricity demand. The trend was reversed from 2021, with the economic recovery leading to higher emissions despite the ongoing pandemic and reduced electricity generation from renewable energy sources. This development is reinforced by the increased use of coal to generate electricity. While these figures underscore the urgent need for a more sustainable energy system, they also provide a roadmap for future action. Renewable energy technologies, such as photovoltaic and wind energy, have made significant progress in recent years and have increased their efficiency. Heat pumps are also key factors in the roadmap for future measures. The decentralized nature of renewable energy technologies enables energy production close to the point of consumption, which significantly reduces energy losses during transmission and distribution.

Promoting and using renewable energy is therefore crucial for the transition to a more sustainable society and reducing our dependence on fossil fuels. As these technologies evolve and become more efficient, they play an increasingly important role in creating sustainable and efficient energy infrastructure that meets the challenges of the 21st century.

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Improving energy efficiency through renewable energy

Renewable energy plays a crucial role in improving efficiency in various sectors. In Germany, the share of renewable energy in final energy consumption for heating and cooling rose significantly in 2022, as a result of savings efforts and the expansion of renewable heat. It is also emphasized that energy efficiency is a central concept for the energy revolution, as our current energy supply system wastes energy in many places. The combination of renewable energy with measures to increase energy efficiency is crucial to ensure a sustainable and efficient energy supply.

Preliminary evaluations show that in 2023, in accordance with the requirements of the EU Directive on the Promotion of Renewable Energies (RED II, 2018/2001), 22.0% of Germany's gross final energy consumption came from renewable sources. This represented an increase of 1.2 percentage points compared to the previous year. Germany had already exceeded its target of 18% in 2020 and will now aim to reach 40% by 2030 in order to meet the new EU climate goals. In 2023, a total of 513 billion kWh (billion kilowatt hours) were used from renewable energy sources. Around 53% of this was accounted for by electricity generation, 40% by the heating sector and 7% by biogenic fuels in the transport sector (fuels derived from plants, plant residues and waste, or manure). With just under 50% of renewable final energy, biomass remains the most important energy source due to its diverse range of applications. Wind energy follows with a share of 28%, followed by solar energy with 14%. The remaining 8% comes from hydropower and geothermal energy. The share of renewable energy has developed positively overall, although there are differences between sectors. While the share of gross electricity consumption has risen to 51.8% in the last ten years, growth in the areas of heating (18.8%) and transport (7.3%) has been comparatively slower.

In order to improve electricity efficiency through renewable energy, there are various approaches and measures that can be taken:

1. Investments in electricity efficiency and renewable energy: Investments in measures to increase electricity efficiency and increase the use of renewable energy sources are crucial. These investments can help to increase the share of renewable energy in the electricity supply and at the same time increase the efficiency of electricity consumption.
2. National goals and regulations: Setting binding quantitative targets at national level with regard to electricity consumption and electricity production from renewable energy sources can create incentives to improve efficiency and increase the share of renewable energy sources.
3. Inland funding: The promotion of renewable energies domestically is preferred over partial import of electricity from renewable sources due to their improved economic efficiency and higher employment effects. This can help to reduce dependence on fossil fuels and increase energy efficiency.
4. Reconstruction of the power supply: A necessary conversion of the power supply to a modern system with flexible renewable energy sources and many smaller producers can increase efficiency and ensure supply. This also includes the increased use of heat pumps.
5. Economical use of energy: Economical use of energy can also help improve efficiency. More efficient use of energy sources can save resources and support the expansion of renewable energies.

These measures show how electricity efficiency can be improved through targeted investments, national goals, domestic subsidies, a restructuring of the power supply and the economical use of energy.

Fossil vs. renewable energy sources and the economic efficiency of heat pumps

Cost developments play a decisive role in the debate about the energy transition. While prices for fossil fuels such as gas and oil tend to rise due to geopolitical tensions, limited resources, and rising CO2 prices, renewable energy is becoming increasingly cost-effective as a result of technological advances and economies of scale. This development not only influences the economic efficiency of heat pumps, which can be operated with renewable energy sources, but also the overall costs of heating buildings.

The initially higher investment costs for heat pumps are therefore increasingly put into perspective compared to conventional heating systems, especially when future energy costs are taken into account. This perspective shows that opting for a heat pump is becoming increasingly attractive not only for environmental reasons but also for economic reasons.

A brief analysis by the Ecological-Social Market Economy Forum (FOES), carried out on behalf of Greenpeace Energy, shows that electricity from renewable energy sources is around 9.7 cents per kilowatt hour cheaper than conventional electricity. Electricity from new wind and solar farms costs around 7.5 cents per kWh, while the cost of electricity from existing coal and gas power plants is around 17.2 cents per kWh. This analysis underlines the economic advantage of renewable energies, even if the EEG surcharge is included in the comparison.

It is becoming clear that it not only makes ecological sense to rely on renewable energy, but that the cost factor also underlines this urgency. It is advisable for consumers to stop relying on fossil energy sources but to consider alternative energy sources, even though they may appear more expensive at first. In the end, this pays off and helps not only our planet but also your wallet.

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How does the efficiency of heat pumps change under extreme conditions?

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Heat pumps in case of frost

The efficiency of heat pumps, particularly under extreme conditions such as frost, is an important issue that is influenced by many factors. In addition to the obvious use of additional heating systems to support heat generation at extremely cold temperatures, other aspects also play an important role. It is just as important to correctly install the system to ensure that it meets the specific requirements of the building and plant. In addition, effective insulation can help to minimize heat loss and further improve system efficiency. Find out in more detail what role plays in minimizing the heat load in the article: Roomwise heating load calculation: The path to an optimal heat pump.

Modern heat pump systems make increasing use of advanced technologies. This includes inverter technology (an advanced control technology in heat pumps that makes it possible to continuously adjust the power and speed of the compressor in order to optimize energy consumption and efficiency), which makes it possible to precisely adjust the pump's performance to current conditions, and intelligent control systems that ensure optimal performance, even at low outdoor temperatures. Research and development play a crucial role in the continuous optimization of these systems. By improving existing technologies and developing new approaches, it is possible to further improve the performance of heat pumps under extreme conditions and thus contribute to the development of more sustainable heating solutions.

The research and development of heat pumps

Research and development in the area of heat pump technology focuses on optimising components, using innovative materials and integrating renewable energy to increase efficiency. Advanced control systems make it possible to adapt the operation of the heat pump to the respective environmental conditions and thus ensure optimum performance. In addition, new concepts such as hybrid heat pumps or cascade systems are being researched to further increase efficiency and reduce the CO2 footprint. Thanks to its versatility and efficiency, heat pump technology is a key tool in the global effort to reduce CO2 emissions and create a sustainable energy future. Heat pumps use renewable energy sources, such as energy from ambient air, and efficiently convert them into heat. They can be used both to heat and cool buildings and therefore offer a flexible and sustainable solution for energy management in buildings. By using innovative technologies and materials, heat pumps have the potential to further increase their efficiency and thus make an even greater contribution to reducing CO2 emissions.

One example of this is hybrid heat pumps, which combine the advantages of air and geothermal heat pumps to ensure high efficiency even in extreme weather conditions. Cascade systems are also part of the research. Here, several heat pumps are connected in series to use heat from various energy sources and thus maximize efficiency.

Funding and regulation for the promotion of heat pumps and the energy revolution

In order to further promote the use of heat pumps and thus drive forward the energy revolution, it is important to create a regulatory framework. These include, for example, funding programs such as tax breaks, direct subsidies or even cheap loans for switching to a heat pump. There is already funding here that consumers can apply for, such as the KfW subsidy 458, which offers a subsidy of up to 70% and can also be easily applied for recently with autarc: Link. With our help, you can calculate and apply for the heat pump subsidy.

In addition, technical standards must be set to ensure the efficiency of heat pumps. Minimum efficiency standards and regular audits should be set. International agreements also help to create and comply with framework conditions. Technological innovations and infrastructural adjustments, such as the expansion of the power grid, are further factors that contribute to making heat pumps more efficient and even more CO2-friendly. Finally, the general public must be made aware of the issue and myths about heat pumps must be dispelled.

Framework conditions for expanding heat pumps and political developments

The Building Energy Act (GEG) sets the energy requirements for new buildings and existing buildings. It promotes the use of heat pumps by setting requirements for the energy efficiency of buildings and prescribing the use of renewable energy sources. Heat pumps can help meet these requirements. In the discussion about heat pumps versus gas heating systems, the question of efficiency and CO2 emissions is often raised. While gas heating systems are cheaper to buy, they have higher operating costs and generate more CO2. Heat pumps, on the other hand, have higher initial costs, but their operating costs are lower and they generate less CO2. They are therefore a cost-effective and more environmentally friendly alternative to gas heating systems. Germany's greenhouse gas reduction targets are that greenhouse gas emissions should be reduced by at least 80% by 2050 compared to 1990. With continuous research and innovation, the challenges of using heat pumps can be reduced and the full potential of this technology can be exploited.

Rules and requirements in the Building Energy Act for heat pumps

In the context of climate change and the need to reduce our CO2 emissions, heat pumps are playing an increasingly important role as efficient and environmentally friendly heating solutions. They use the available heat from the environment — from air, soil or groundwater — and convert this heat for heating purposes. In this context, the Building Energy Act (GEG) is an important element, as it sets out the energy requirements for new and existing buildings.

The GEG promotes the use of heat pumps by setting requirements for the energy efficiency of buildings and prescribing the use of renewable energy sources. In this way, the law helps to reduce the demand for fossil fuels and thus to reduce CO2 emissions.

However, there are also challenges when using heat pumps in the context of the GEG. One of them is their efficiency under extreme conditions, such as frost. Despite these challenges, the GEG offers enormous potential for the use of heat pumps through its regulations and requirements. With continuous research and innovation, these challenges can be overcome and the full potential of this technology can be exploited.

Heat pump instead of gas heating

In the current era of energy efficiency and CO2 reduction, many are asking themselves which heating systems are the most effective and sustainable. Two technologies that are often compared are heat pumps and gas heaters. Both have their pros and cons, so it's worth taking a closer look at them.

As we know, heat pumps use the available heat from the environment — whether from air, soil or groundwater — and convert it into usable energy. This process reduces the need for fossil fuels and thus leads to a significant reduction in CO2 emissions. They may have higher acquisition costs, but their operating costs are lower and they emit less CO2. They are therefore a cost-effective and more environmentally friendly alternative to gas heating systems. On the other hand, gas heaters are cheaper to buy. However, they have higher operating costs and emit more CO2. As a result, they could be more expensive in the long run and are less environmentally friendly than heat pumps.

Of course, there are also various challenges when it comes to heat pumps. As already described, professional installation is extremely important and weather conditions such as frost can also pose a challenge in efficiency. Despite these challenges, switching from gas heating to a heat pump offers enormous potential for improving energy efficiency and reducing CO2 emissions. With continuous research and innovation, these challenges can be overcome and the full potential of this technology can be exploited.

Is noise still an issue with heat pumps?

The discussion about the volume of heat pumps has often caused unrest in the past. Depending on the model and installation, heat pumps may produce noises that can be perceived as annoying, but the situation has now improved significantly.

With a heat pump volume calculator, you can calculate the exact volume of your heat pump. A typical heat pump produces around 30-60 decibels of noise, which is the equivalent of a whisper to a normal conversation. The volume depends on various factors, such as the quality of the heat pump, the installation and the location. However, the noise from outdoor equipment can be annoying for residents. Fortunately, there are various measures to reduce noise. The use of mufflers or soundproof housings can effectively reduce noise levels. Optimum installation is also important to minimize vibrations. Best practices in planning and installation help prevent potential noise issues. For example, the heat pump should be placed in such a way that sound transmissions are minimized.

If a heat pump is louder than expected due to faulty installation, there are various solutions. An incorrect installation can result in increased noise, for example due to insufficient sound insulation or inconvenient placement. In such cases, it is advisable to call in a professional to identify the source of the problem and take appropriate action.

There are specific solutions for reducing noise for indoor and outdoor installations. Modern heat pumps have already become quieter, but additional measures such as sound-absorbing materials or vibration-damping elements can further reduce operating noise.

Noise protection is also crucial when selecting and positioning a heat pump. An appropriate distance from neighboring properties and avoiding direct proximity to bedroom windows are important aspects. Through careful planning and appropriate measures, the background noise of heat pumps can be effectively minimized so that they represent a quiet and efficient heating solution.

Future prospects for heat pumps

The future of urban heating supply is facing significant change in order to increase efficiency and environmental friendliness. Karl-Heinz Stawiarski, managing director of the Federal Heat Pump Association, sees heat pump district solutions as an answer to these challenges. This innovative solution is becoming increasingly popular with cities and municipalities, as they can generate renewable heat decentrally and distribute it to surrounding houses. In this way, densely built-up settlements can use sustainable heat without their own heat sources. The use of local heating in combination with heat pumps offers two approaches:

• With traditional local heating, the heat generated is raised centrally to the required temperature level and fed directly into the heating system of the houses.
• An alternative method, cold local heating, feeds the heat into the network and brings it to the individual temperature level on site using a heat pump. This concept is used, for example, by the city of Ludwigsburg to supply new buildings and existing districts.

The heat source for the heat pump is developed by using geothermal energy, groundwater, waste water or waste heat from various sources. These sustainable methods maximize the efficiency and environmental friendliness of heat pumps. Local heating combined with heat pumps offers an environmentally friendly supply of entire districts with relatively little effort. By avoiding gas pipes, costs can be saved and greenhouse gas emissions reduced. The increasing use of renewable energy and the high efficiency of heat pumps contribute to compliance with energy saving regulations and make them an attractive option for future heat supply.

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