How to Encase a Window Air Conditioner

Prefabricated Cases

• Air conditioner manufacturers sell prefabricated metal cases to encase window units. These cases are five-sided boxes that mount to a window frame and conceal the portion of the air conditioner that sits outside your home. They feature vents that line up with the ventilation system of the air conditioner to allow for uninterrupted airflow. Installing this type of case is among the simplest ways to encase a window air conditioner.

Building Your Own Case

• Building your own air conditioner case may save money, though it will require you to take measurements and construct a custom case. The case must not only fit your air conditioner, but also accommodate its ventilation and match the width of your window. Construct the case out of plywood and paint the exterior to match your home for a discreet look. Use metal brackets to attach the case to your window frame before reinserting the air conditioner.

Insulation

• Encasing a window air conditioner offers an opportunity to make it more efficient. Window air conditioners are susceptible to taking in moisture from outside and making your home more humid inside. To prevent this, make or purchase a case that is larger than your window unit and fill the space between the air conditioner and the case with foam insulation. Whether or not you add insulation, use silicone or acrylic caulk to seal the inside corners and seams of a homemade plywood case.

Pros and Cons

• Encasing a window air conditioner has a number of benefits. It makes the unit more difficult to remove from outside, thus reducing the risk of theft. If the case is well insulated and properly open to ventilation, encasing a window air conditioner can also reduce moisture in the home and improve overall efficiency. However, encasing also has drawbacks. They include the need to alter a window frame to attach the case, the cost of materials and the difficulty posed by moving the unit from one room to another, which is much easier when there is no case to move.