This master thesis examines how buildings should be designed in the future, in terms of facades and cooling systems, in order to achieve desired indoor temperatures. The basis of the thesis is the expected increase in outside temperature, due to climate change, and the fact that several hundred people died in 2018, as a result of the heat wave that was in Sweden that year. To examine future indoor temperatures, a model of an apartment building in southern Stockholm was created in the software IDA Indoor Climate and Energy, IDA ICE, as well as future climate files for the same geographic position. The climate files were based on future climate scenarios and local data, in order to be as realistic as possible. The model of the building was simulated during the summer months, beginning of June to end of August, with the focus of receiving the indoor temperatures for year 2030 and 2060. For the year 2060 a sensitivity analysis was made in order to see how a change in building design, to analyze how it may affect the indoor temperatures.The results indicates that the indoor temperatures will continue to increase, as a result of the climate change, and that building design played a small role in lowering the indoor temperatures when it comes to changes in facades, but a bigger role for cooling systems. Peaks of 33°C for the year 2060 was lowered to 25°C when cooling systems where implemented, while changes in facades only lowered the peaks to 32°C.The conclusion for this master thesis is therefore that when it comes to buildings in the future, cooling systems should be considered, as well as changes in the facades, in order to achieve desired indoor temperature. Solar film on the windows and awnings can be used to reduce the indoor temperature, but the balance between daylight admission and heat transmission is important to consider. Rotation of the building and the presence of shading objects, such as balconies and surrounding buildings, also affect the indoor temperature in apartment buildings and should therefore be considered in new construction.