Last updated on March 10th, 2024 at 03:04 pm

Window unit air conditioners are a terrific alternative to those who can’t afford, or don’t want, a central unti air conditioner. They use less energy, are portable, and generally install very easily. If you aren’t careful though, the money you save on these units might actually be going out the window as lost energy.

Here’s what can go wrong, and how to prevent it (or at least fix it)

1. Forgetting to install the insulation. There is a small strip of foam insulation that is positioned between the window panes that “slide” open. This prevents drafts or air from escaping from the cooled room. Not installing this will cause heat loss, thus making your A/C run longer and possibly harder.
2. Not positioning the A/C with a “tilt”. Most units have the bulk of the unit hanging outside, over the bottom shelf or window sill. When installed correctly, most units won’t be perfectly parallel to the ground, it will actually by tilted more outside. This is done for two reasons. First, since the unit is outdoors it is susceptible to the elements, like rain. Rain will get into the main part of the unit. The tilt allows the collected rain water to run out the drain holes. Second, most air conditioners have a dehumidifier, so in the process of cooling the room excess moisture is collected. And most units, during the compression cycles, produce condensation as a byproduct, which is then pooled outside. The water will simply drip out.
3. Bottom “padding” is not on the pane or window sill. On most units, there is a bottom foam layer the sits directly on the sill. This minimizes vibration and also minimizes heat loss below the unit.  Make sure the foam layer is doing its job.
4. Make sure the unit is bolted/screwed down, and the side shutters are expanded fully.

Does anyone have any more tips?