I have purchased a flat and occupied in Feb2014. This is a second purchase flat taken from the builder and the last flat to be sold in the apartment. Opposite to my entrance door there is an AC outdoor unit which belongs to the opposite flat owner which was already installed by the time we shifted to our flat. This AC Outdoor unit was placed diagonally opposite to the entrance, which makes sound/noise whenever it is been used. Ideally this outdoor unit has to be installed outside the common area. But it is installed inside the common area which is clearly visible. As Feb2014 is the end of winter season, we didn't notice the disturbance much from the opposite flat AC Outdoor unit. But we have eventually observed that the hot air is coming into my house thru my entrance door. I cannot keep my flat entrance door shut all the time. Atleast in the working timings I have to keep it open for the fresh air. I have been objecting on the same and taken-up to the flat owner and also to the apartment association and till date there is no positive response. What is the next level of escalation so as to take this issue forward.