Our Window Aircon suddenly doesn't cool as much as it used to (Both in low cool and high cool modes). The air coming out of the unit is cold when You go near the window where the cold air comes out but all in all it doesn't cool the whole room as it used to (It's been used regularly for 1 year). It also Ices up starting from 2 points of the coils in the front (Lowest coil and middle coil) and it continues to develop ice going upwards).

At first I thought it was just dirty so We called in some Maintenance Crew to clean it up. After cleaning it seems that it still doesn't cool as it used to as well.

The Compressor is alright as it turns on normally) and turns off when it feels that the room is cool enough (This only happens during around dawn when when the surrounding is a bit cold as well but during the hot afternoon it doesn't turn off because mainly the room isn't cooling enough).

I'm now suspecting it probably is low on Freon or something but it could also be wrong.

Any help will be appreciated, thanks. :)