How can I level off a wall?

Air Conditioning: Does mounting AC at a lower level on wall saves energy?

• Let's say there is a room with brick walls and concrete roof with height of around 12 feet. A split AC is mounted on wall at a height of 10 feet. Outside temperature is usually more than 45 degree Celsius. Given the fact that cold air settles downs and hot air moves upward, at any given point of time, in the room, air will be cooler at  floor level than the air near roof. Also the roof remains really hot because of direct sunlight it receives. Now considering the fact that we only need cool air near floor or at bed level only, the AC seems to waste energy in cooling the entire room's air. I am assuming that the temperature sensors are mounted on AC unit and those won't stop AC till the air at 10 feet level reaches desired temperature. I am wondering if we mount mount it at ground level, won't it save energy.

• Answer:

  If your goal is only to cool the room near the floor, then yes, mounting the AC near the floor is probably better. Otherwise, you want the AC near the middle or wherever it has the best airflow. It will run more effectively by pulling in hotter air, rather than re-cooling the same colder air over and over. It sounds like the outside temperature is pretty hot. Make sure the outside of the AC unit is in the shade and has some airflow around it. That will help it cool more effectively.