How to Install a Wall Mounted Air Conditioner/Heater

air conditioner mounted to a wall in the corner of a room
What You'll Need
Tape measure
Stud finder
Saber saw
Masking tape
Hacksaw or reciprocating saw blade

Installing or fixing an air conditioner heater wall unit is similar to working with a window unit. Installation is usually not difficult and there are only a few minutes where having a second pair of hands makes the job go faster, but isn’t necessarily required. Troubleshooting or having to fix a wall unit or cracks in the wall left over from the installation is often just as straightforward.

Insure Compatibility

Wall units work much the same as window units except for the fact that the installation will be flush mounted against a wall. There are some benefits to this such as not having the sometimes unappealing look of the back end of a window unit greeting visitors when they come by the window, but there are some problems as well. It’s advisable to check ahead of time to be certain that your home can accommodate the wall unit. For instance, some mobile home manufacturers recommend against using a wall unit in their products. Having a wall unit means cutting into the wall itself, so be sure the wall you will use can take this stress and support the weight of the unit you are considering. Measuring before the job can make installation a faster task.

Step 1 - Choose a Location

wall mounted heater

Choose the space you want the wall unit to be placed in and measure the area by its width and length. Make sure there is nothing in this area that will affect the workings of the wall unit.

Step 2 - Check for Obstructions

Go over this portion of the wall you have chosen with a stud finder to make sure there’s nothing that will prevent you from being able to fix the unit here.

Bring the Wall Unit Home and Install It

Choose the wall unit you want and purchase it. To install, there are items you will need.

Step 1 - Review the Wall Unit Instructions

Familiarize yourself with the wall unit manual and instructions.

Step 2 - Saw out the Interior Opening

reciprocating saw

Using the masking tape make an outline of the wall for the opening. Be sure this is definitely where you want the wall unit to be. Using a reciprocating saw or similar blade, cut the drywall. Then remove this piece of drywall along with any insulation behind it. You might want to save the insulation.

Step 3 - Create the Exterior Wall Opening

Using a saw blade create a hole for the exterior siding. Drill a small hole in the corner of the opening for the mounting. Using the saber saw or similar tool cut a line from each hole. Then remove the siding to expose the wall opening.

Step 4 - Mount the Unit

If possible call in favors from family and friends to help you lift the wall unit into place and mount it.

To fix a wall crack or other issues, use wall sealant available in most hardware stores to repair these issues. A wall heater unit works in a similar way and can be installed using the same methods.