When determining the appropriate BTU size for an air conditioning unit, it's important to take into account several factors in addition to the size of the room, such as the level of insulation, the number of windows, and the height of the ceiling. However, as a rough estimate, a room with an area of 26 sqm would typically require an air conditioner with a cooling capacity of around 9,000-12,000 BTUs.
Given that your kitchen has some east-facing windows and there is a house located 5 meters away, it's possible that the amount of heat entering the room through the windows could be reduced. However, the L-shape of the room and varying ceiling height could affect the cooling efficiency of the air conditioning unit.
Based on the size of the room and the varying advice on BTU size, it may be best to consult with an HVAC professional to get a more accurate estimate of the appropriate BTU size for your kitchen. Additionally, Daikin is a well-regarded brand, and it's important to choose an air conditioner that has a high Energy Efficiency Ratio (EER) to minimize energy consumption and reduce your energy bills.
