The ORF recently reported that around 1,100 heat-related deaths were to be reported in Austria in 2024 - most of the victims are likely to be found in urban centres. If the results of the study "Urban cooling demand in Austria 2030/2050" - commissioned by the former BMK - are to be believed, the negative effects of the expected future rise in temperature on health are likely to intensify. This study assumes that the average number of cooling degree days in Austria will increase by 50 % to almost 100 % by 2050. The cooling demand for the year 2050 varies between 3 TWh and 19 TWh - depending on the author of the study and the assumption of the framework conditions.

The cooling demand maps based on the general comfort model - created as part of the aforementioned study - show an absolute cooling demand of 3.5 to 6.3 TWh/a for homes and offices in 2050, depending on the scenario.

The demand for cooling in 2050 is significantly high in eastern Austria, primarily in Vienna and its surroundings, in Burgenland and along the Danube valley - compared to other municipalities.

According to the results of the study, the maximum absolute cooling capacity of homes and offices in Austria - depending on the scenario - will be 12.9 to 15.4 gigawatts (GW) in 2030 and 13.9 to 18.6 GW in 2050. Of this cooling capacity, around 76-78% is attributable to homes and the rest to offices. It should be noted that the cooling capacity does not correspond to the required electrical power. The European Seasonal Energy Efficiency Ratio (ESEER) must be taken into account. This means that the required electrical power corresponds to approx. 1/5 -1/4 of the cooling power generated.

The figures show that the noble intention of "cooling the city by greening and planting trees or installing shading devices" is correct, but the effect will only unfold in many years - trees grow slowly. As a result, the number of heat-related deaths could possibly increase significantly compared to 2024.

The installation of air conditioning systems is proving to be quite difficult in older buildings, but also in some new builds - for various reasons, such as tenant/landlord issues, legal regulations in the German Condominium Act, etc. The argument put forward is that the installation and operation of air conditioning systems would increase energy consumption and consequently also greenhouse gas emissions. Based on this argument, the installation of air conditioning systems is not authorised by some housing developers/building management companies

The claim that energy consumption would increase through the use of air conditioning is correct for the summer period. However, as the number of hours with negative electricity prices is currently increasing - mainly in summer - and the electricity demand generated by the air conditioning systems correlates with the electricity generation peak, the air conditioning systems could help to reduce the volatility of electricity prices. It should be noted that although the maximum cooling demand would occur when the PV systems would also deliver the greatest output, human behaviour must also be taken into account. Very often people come home after work and only then switch on the air conditioning - but then with the highest output of the, possibly oversized, system - thus when the sun is no longer shining or shining to a lesser extent - consequently the PV systems produce less electricity.

The much more important argument, however, is that most air conditioning systems (split units) can also be used as heat pumps - and could therefore function as room heating. This means that in winter or in the transitional period, these air conditioning systems would even save energy when used as space heating. This is because in the transitional period and beyond, these appliances achieve performance figures of up to 4, meaning that you get approx. 4 kWh of heat for every kWh of electricity used. As a result, energy consumption and the resulting greenhouse gas emissions in the residential and office sectors would be reduced. In addition, in areas where district heating cannot penetrate for economic or performance reasons, the climate targets could be realised more quickly
As the energy required to generate heat is significantly higher than the energy required to generate cooling over the course of a year, it is safe to assume that significant savings in both energy and greenhouse gas emissions can be achieved each year.

Although the authors of the above-mentioned study describe cooling generation options - including the advantages and disadvantages of each technology - they do not make any recommendations. Nevertheless, it can be assumed that all types of cooling generation (in reverse operation, heat generation) would require considerable electricity outputs and quantities. This means that the power required by the air conditioning systems must be taken into account in the electricity grid capacity and must therefore be included in the grid development plans. In these areas, where no district heating is available and heat pumps would be used for space heating and hot water supply, it is necessary to check whether the necessary increase in electrical output would not in any case be covered by the required increase in output due to the air conditioning systems.