A 0.5 HP (horsepower) window-type air conditioner may not be sufficient for cooling a 12-15 sqm (square meter) room adequately. The cooling capacity of an air conditioner is typically measured in British Thermal Units (BTUs) or kilowatts (kW), rather than horsepower.
To determine the appropriate cooling capacity for a room, you can use a general guideline of approximately 20 BTUs per square foot (or 60-70 watts per square meter). In this case, for a 12-15 sqm room, you would need an air conditioner with a cooling capacity of around 2,400 to 3,000 BTUs (or 700-900 watts).
A 0.5 HP window-type air conditioner typically has a cooling capacity of around 4,000 to 6,000 BTUs (or 1,170-1,760 watts). It might be more powerful than necessary for a 12-15 sqm room, which could result in overcooling or increased energy consumption.
For optimal comfort and efficiency, it is generally recommended to choose an air conditioner with a cooling capacity that matches the size of the room. Consider selecting an air conditioner with a cooling capacity of around 2,400 to 3,000 BTUs (or 700-900 watts) for your 12-15 sqm room.