There are many acceptable places to put your air purifier, such as next to a desk, in the corner of the room, etc. The best places are the ones with 1-2 feet of free space around the machine to allow air circulation. However, places that are not recommended are places close to direct heat, vents, or smell sources (i.e. next to air conditioner, fireplace, fan, etc.). The direct proximity of those could have an influence on the correct function of the Air Quality sensor or AeraSmart sensor of your unit.