Paint indoor air conditioners the same color as the surrounding wall. You will not hide the unit but the paint will provide camouflage and you will not obstruct the vents. Or, if you're feeling particularly artistic, paint it a color or add a design that complements the decor of the room.
Install a backless (cabinet backs are easy to remove), hinge door, wall-mounted cabinet over the unit. The cabinet must be wide enough to extend beyond the unit by 1 to 2 inches on each side and deep enough to extend 1 to 2 inches in front of the air conditioner. Close the cabinet door when the unit is not in use and open it when the room need's cooling.
Cover the indoor air conditioner with curtains. This is an easy solution if the unit is in a window in which a rod has already been installed. If not, create a faux window on the wall by mounting a curtain rod on the wall above the window. Pull the curtains aside when you need air.
Install a shelf just below your indoor air conditioner. On the shelf, place a fireplace grate, vintage holed tiles on a stand, sculpture or other decorative pieces that allow air circulation. Put a few houseplants in front of the air conditioner but remove them when the unit is operating. The blowing air would desiccate the plants' foliage.
Place a sheer fabric screen in front of the air conditioning unit.
Purchase an air conditioner cover from your local home and garden center. Bring your indoor air conditioner's measurements with you when you shop.
Erect an outdoor wooden screen in front of your outdoor air conditioner unit. You can find these large screens in a variety of styles and colors online or at many home and garden centers. Install them on three sides of the unit, according to the manufacturer's instructions included in the kit, to provide camouflage. Leave the fourth side open to allow easy access to the unit.
Plant shrubs around your air conditioner. Keep the shrubs at least two feet from the unit on all sides. Plant one large shrub on the most visible side, or plant shrubs on all three sides. The shrub must be at least three feet in height and width at adulthood to provide sufficient coverage. Faster-growing shrubs will provide coverage more quickly. Spring is the best time to plant shrubs.