Well, A window AC is fitted on, oh well, a window. All of its machinery is in one large box, front of which is into your room and throws cool air in and sucks warm air out, while the rear is usually placed in such a way that its out of the house, like a wall in the room whose other side is outside. The reason for this is that window acs throw hot (read very hot) air from their back.
A Split AC is, well, splitted into two parts, the first part is fitted in your room at some height mostly, coz they throw cool breeze from their underside. The other part which throws warm air out is fitted somewhere else, and both of these parts are connected by some equipments (i donno exactly what, i have window AC only). So these ACs are mostly used in situations like where there is no suitable wall in the room for window AC, coz if you put that with its backside in your home, your room will become cool and rest of your house will be like hell.
Split ACs are more expensive than window AC, the differce can be 4-8 thousands depending on brand, model and compressor size etc.
I think for your room a 1.5tonn ac will suffice, window or split, that you decide based on your room's structure.
I would recommend Hitachi ACs anyday, they are a little expensive in beginning but others prove much more costlier in the long run. Hitachi ACs use japanese made components, while the others, mostly if not all, use China made compressors and other components, which have a short life span. They tend to give problems and/or less cooling after 1.5 to 2 years. I have two Hitachi's and they are working excellent for 3 years. So its the sitution like Pay Me Now or Pay Me Later.
LG, Samsung etc are available in 1.5 Tons window variants for about 16-18K and HItachi's Mid Range model is for 24K. I dont have much idea about split ones, may be they are available for a price difference of 4-5K.
Hitachi ACs also consume significantly less power, they have 5 working power levels, the least one being about 550 watts and the highest one being 1600 Watt. They step through these levels depending upong the level of cooling you do.
Also do keep in mind that there are other costs also, First you'll need a separate line of about 100mm wire from your electricity meter to your place of fitting the ac. Plus some wood and iron work, if its not already done. Also, AC needs a separate voltage stabilizer which would cost you about Rs 4k.
I hope this information proves useful for you.
Good Luck!
