Rethinking Space Cooling for a Sustainable Future

Sustainable space cooling is essential for thermal comfort, energy efficiency, and climate adaptation in Europe amid rising temperatures.

The first thing to note is that in CoolLIFE, we don’t address all possible space cooling. We are focused on space cooling as an energy service to maintain thermal comfort in buildings, and that’s especially during warm periods.

Generally, space cooling can also be about maintaining specific temperature in spaces like data centres, food storage, etc. However, that part is not covered in the project. One of the usual risks we see when speaking of space cooling is that it may be directly associated with air conditioning system. While, in practice, air conditioning can be useful in some situations, it is not always the best solution. And the best way would be first to consider possible solutions to deliver energy service by addressing the actual needs in cooling.

There are other solutions besides conditioning systems, and we should start by considering real cooling needs.

So, cooling needs are typically defined as the amount of heat that you need to remove from the rooms that are inhabited in order to stay below the target temperature, which is also called set point temperature. Air conditioning systems are one of the solutions to transfer the heat from indoor to outdoor. But there are other solutions to consider. The first step should always be considering the options to reduce cooling needs in practice. 

For example, at your barn level, this means developing or maintaining green areas that will reduce the accumulation of heat. In urban areas, at the building level, it may mean shading the façades or improving the insulation of the building envelope. This will reduce the natural transfer of heat from outdoors to indoors. Another point to keep in mind is the internal heat gains or sources. And here a usual example is lighting, when we have replaced incandescent lighting with LEDs, this has considerably reduced the heat generated from lighting. Cooling needs can also be reduced by behavioural measures. Here, we usually speak about adaptive comfort, which means that the level that you will consider as appropriate in an indoor environment may vary depending on certain conditions like humidity, the number of successive days with high temperature, and so on. So, obviously, what we want to highlight here is that there are other solutions than air conditioning systems and that we should start considering the actual needs for cooling. 

Since the early 2000s, I would say that there is a clear increasing trend in the equipment rate of air conditioning systems. And if there are more air conditioning systems, this results in higher energy consumption from space cooling. Nevertheless, the challenge is that it still represents a very small share of the total final energy consumption in the European Union. That’s probably around 2 to 3% of the total final energy consumption. And this is because this consumption mostly occurs during a few weeks per year. If you compare it to the heating season, that would be several months. So that explains why the use of space heating is much more systematic than space cooling. However, there is a clear trend in the increasing equipment rate and the increasing temperature in summer. And that’s especially the case with the more frequent and longer heat waves. That means we see peak electricity demand in summer due to space cooling, and that can put the electrical system at risk. That can even lead to blackout. This was observed, for example, in Italy in 2023.

That’s not the only reason why space cooling is an important issue.  And I would say, from a human perspective, the main issue is health. The European Environment Agency reported a summary from the literature that estimated that warmer summers and heat waves caused over 70,000 excess deaths in Europe in 2003 and, similarly, more than 60,000 in 2022. So, we see that it is a very serious issue.

The European Environment Agency reported a summary from the literature that estimated that warmer summers and heat waves caused over 70,000 excess deaths in Europe in 2003 and, similarly, more than 60,000 in 2022.

And when looking more specifically at climate change from the point of view of greenhouse gas emissions, air conditioning systems can also represent a major risk because they use refrigerants. And these refrigerants may have a very high global warming potential, which is the contribution that they may have to global warming. And this global warming potential might be 1,000 to 10,000 times higher than the one of CO2, which is the most well-known greenhouse gas. So, the risk here concerning greenhouse gas emissions is particularly high when the air conditioning system is not well-maintained, because you might have leakage, and when it is not disposed of properly, for the same reason, it may cause leakages and greenhouse gas emissions. 

So, as we deal with building, when we speak about space cooling, that’s the built environment. The first challenge is that the renewal rate of the building stock is very slow. In Europe, it’s usually assessed at around 1% per year, or even less in some countries, and that’s a major problem. Because new buildings can be designed to limit their cooling needs, they can favour alternatives to air conditioning systems. When we think about space cooling during the design phase of the building, the investment costs are much lower. More solutions can be considered, so it’s easier compared to considering the same for the case of existing buildings. 

One solution to reduce the cost of implementing solutions in existing buildings can be to incorporate actions to reduce cooling needs into planned renovation projects. Just as an example, if you try to install shading devices, it will cost less when it is done as part of a planned façade restoration, because part of the fixed cost of renovation would be the same. However, in practice, the space cooling aspects are rarely considered in renovation projects because they have other purposes. They are carried out for structural needs, aesthetics, or reducing heating consumption. 

And on top of that, the renovation rates, just like the renewal of the building stock, are also low. That’s the first point. The second point is that in most European countries, the primary energy end-use in buildings remains space heating. This is why there is much less information and awareness about space cooling compared to space heating, especially when there are policy measures or projects to improve the energy performance of buildings.  

If we look from the perspective of building owners and occupants, the risk is that they will consider air conditioning systems as the main, or even the only, solution to meet their cooling needs. And this is further worsened by the evolution of social norms. For example, consumers will consider space cooling in an area when a heatwave is announced, and they want to prepare for it. We have evidence of this. If you look at the press every summer, you will regularly see articles mentioning peaks in sales of air conditioners, including mobile devices, during warm summers. 

There have been studies for many years raising awareness about climate change and the increasing trends in temperatures and heatwaves. So, there is a strong need to anticipate these increasing cooling needs and to organise more sustainable responses. These needs for anticipation, coordination, and planning are also important due to the diversity among buildings, owners and occupants. It is not the same to consider space cooling for residential buildings as for offices, for example. Similarly, the choice of solutions also depends on income level. 

On the side of public authorities and policymakers, one of the major challenges is to address space cooling in an integrated way, while different levels and responsibilities are usually spread across jurisdictions. What does this mean? It means that, for example, the regulations on air conditioning systems or cooling devices in general are primarily set at the EU level. At the same time, regulations for buildings are mostly specified at the national level, and urban planning is in the hands of municipalities. So, it is also a multi-governance issue, which makes it more challenging to address in a comprehensive or consistent approach. 

As I mentioned, the most direct way it is addressed is through regulation for cooling devices. The EU regulations cover the dominant space cooling technologies, so, to use technical jargon, these are technologies working with vapour compression systems. These regulations include energy labelling regulations that ensure minimum and harmonised information for consumers. This information is about efficiency and energy consumption of devices. Then you have the ECO design regulations that are meant to remove from the market the least efficient devices, as well as the F-gas regulation that is related to refrigerants, which I mentioned earlier, with the objective of planning the phase-out of the refrigerants with the highest global warming potential. 

These regulations are periodically revised to follow the developments in R&D and the market, as well as to strengthen the provisions and support market transformations towards more efficient and climate-friendly alternatives. One important point to keep in mind is that EU regulations apply directly and uniformly in all Member States. However, their actual implementation may differ from one country to another because market surveillance is managed by the Member States. Then you have the set of directives – directives of energy efficiency, energy performance of buildings, and renewable energy sources – that all include some provisions relevant to space cooling. 

These directives are transposed by Member States into national legislation. This is related to the subsidiarity principle, which means that Member States keep some flexibility in how they achieve the objectives agreed at the EU level. This is meant to allow them to tailor their policy measures to national specificities. However, that also results in quite a few differences, especially in topics like space cooling.  

If we look more specifically at the Directive on Energy Performance of Buildings (EPBD), this is the one setting the framework for building regulations for both new and existing buildings. This framework specifies that space cooling should be considered among the end uses when calculating the energy performance of buildings. However, as space cooling represents, in most cases, a small share of a building’s energy consumption, this framework does not necessarily result in provisions that would be specific to reduce cooling needs.  

The latest recast of this Directive, which was adopted in 2024, has emphasised the need to consider thermal comfort. So, let’s see in the coming years, when Member States transpose these new provisions, if it’s an opportunity to enhance the requirements for minimising cooling needs, especially in new buildings, and to ensure that when there are measures for major renovations, they do not worsen the conditions for summer comfort. 

The latest recast of this Directive, adopted in 2024, emphasised the need to consider thermal comfort. So, let’s see in the coming years if it provides an opportunity to enhance requirements for minimising cooling needs in new buildings. 

In parallel, we see the development of regulations for climate-resilient buildings, which could also help address these issues. From a more planning perspective, the Directive on Energy Efficiency includes provisions for efficiency in the supply of heat and cooling, particularly requiring Member States to prepare and regularly update comprehensive assessments on heating and cooling. In principle, they should go from assessing cooling needs by technology type and sector to planning policies and measures to meet these needs and promote the development and adoption of most cost-effective solutions.

Initially, this was meant to identify opportunities and promote district cooling. But in practice, what we see when reviewing the comprehensive assessments reported by Member States is that most countries have focused their assessments and measures on heating, which is normal because heating represents the largest share of energy consumption. Considering both heating and cooling together, along with the lack of data about space cooling, make it more difficult to complete this assessment for the cooling part. 

In the latest recast of the Energy Efficiency Directive, which was adopted in 2023, a new provision was added to require municipalities with more than 45,000 inhabitants to prepare local heating and cooling plans, which could also be a driver for space cooling to be better addressed. However, as mentioned in the comprehensive assessment, it is likely that these plans will focus on heating first, except in areas where space cooling is already a critical issue. 

Then, if we look at renewable energy sources, the latest amendment to the related Directive was also adopted in 2023, and it has introduced a specific target to increase the share of renewable energy sources in heating and cooling consumption as mandatory. But again, in practice, the focus is likely to be on renewable heat for the same reasons – due to the small share of cooling compared to heating, but also because cooling is mostly supplied with electricity. Nevertheless, geothermal and heat pumps may contribute to this target. The same Directive also requires Member States to carry out an assessment of the potential for energy from renewable sources and the use of waste heat and waste cooling in the heating and cooling sector. 

In the latest recast of the Energy Efficiency Directive, adopted in 2023, a new provision requires municipalities with more than 45,000 inhabitants to prepare local H&C plans. 

This is, for example, meant as an input to the comprehensive assessment I mentioned just before, but for the same reason, it is likely that these assessments are mostly focused on renewable heat and waste heat. The last part of the EU framework is the European Climate Law and, more generally, the framework for adaptation. The Climate Law was adopted in 2021, and it enforced the requirement for Member States to adopt and implement national adaptation strategies and national adaptation plans in most countries. When dealing with adaptation, increasing temperatures and heat waves are important issues. However, we see that the way they are addressed varies quite significantly among countries.  

A final point about the EU policy framework is that, since the Clean Energy for All package in 2018, the EU policy framework has aimed at promoting an integrated approach to energy and climate issues. This has been particularly encouraged by the Regulation on the Governance of the Energy Union and Climate Action, which was adopted at the end of 2018. It is meant to consider interactions and coordination, especially in planning for several aspects. So, the supply side and demand side of energy, energy efficiency and renewable energy, and mitigation and adaptation should be considered together. 

One example of this is the linkage between what I mentioned earlier- the assessment of renewable potential and the Comprehensive Assessment on Heating and Cooling – also together with the National Building Renovation Plan, which was formerly known as the Long-Term Renovation Strategy. This can help strengthen policy and planning consistency, because all these strategic documents will then use the same scenarios, the same data, and the same assumptions. However, this may also mean that the focus will remain on major issues, and that issues such as space cooling could be neglected compared to heating, for example. 

That’s a good question, and maybe the first point to raise about this is the major differences in context among countries. To set this background, we know that four countries – Spain, Italy, France, and Greece – would represent close to 80% of the useful energy demand for space cooling in the Energy Union. This means that most of the energy consumption from space cooling is concentrated in a few countries.

At the same time, there are also countries that are not visible in these statistics because they are small, but they still need to address space cooling because it represents a significant share of their own energy consumption. For example, this is the case for Cyprus and Malta. Altogether, this explains why space cooling is addressed in various ways and to varying extents among Member States. And this is not only due to the differences in cooling needs related to climate, but also to equipment rates, social norms, etc. 

We can see this in national regulations for buildings. For example, in countries where the need for space cooling is limited, their building regulations often explicitly address space cooling. 

It will still be included because of the requirement set by the Directive on Energy Performance of Buildings. As a result, it will be considered when calculating the energy performance of the building, but there will be no specific provision or requirement dealing with space cooling. Whereas in countries where it is a much more critical issue, we see a trend towards provisions such as limiting what is called discomfort. This can be considered by either differentiating winter and summer (i.e., considering winter discomfort and summer discomfort) or assessing discomfort over the entire year. The approach assesses the number of hours where the indoor temperature will not be appropriate, either because it’s too cold in winter or too warm in summer. This is an interesting approach because it does not limit the options considered to technical solutions, as comfort is directly related to behaviours, for example. And another point worth mentioning is how Member States coordinate their actions between the national and local levels.  

We have spoken about buildings, and while building regulations are mostly specified at the national level, many of the solutions needed to provide sustainable space cooling lie in the hands of local stakeholders, especially municipalities. 

We previously mentioned urban planning and limiting the accumulation of heat in urban areas earlier. This is one of the examples where the role of local stakeholders – urban planners, architects, and building engineers – is essential.