A room air conditioner is ideal for rooms up to 200 sq ft where one of the walls is exposed to the outside. In case of budget and space constraints, one could go for a Window AC.
Though window units are cheaper and easy to install; Split ACs are quieter in operations, more aesthetically appealing and have better air distribution. If there are no exposed walls, a Split AC is the only option. Split ACs have two units – a compressor unit outside and the indoor unit inside. Since the compressor is kept outside, noise levels are lower in a split air conditioner as compared to the window air conditioner. However, installing the split units may require some renovation work, which implies a monetary investment.