Wall unit air conditioners offer an alternative to window AC units and are typically mounted in spaces that are actually cut-out of your home's exterior walls.

These types of air conditioners are not for everyone. If you rent your home or live in an apartment building, wall units are not an option as cutting through your walls is neither permitted or desirable.

However, wall unit AC's are sometimes preferred by those who do not wish to take up window space, block out sunlight, or are more concerned with theft (wall units do not provide the sort of "easy entry" that window AC units might if they are not installed properly or are on the first floor).

Wall unit AC's offer all the options of a window air conditioning unit as well as some additional ones. Heat pumps often come along with these sorts of models, which allow you to use the unit for both cooling and heating. Electronic temperature readouts and timers are also usually standard features on wall unit air conditioners. Some wall unit AC's also come with remote controls, which make it easy to change the settings from across the room.

Installation for wall unit air conditioners is significantly more involved than standard window AC installation. These units sometimes weigh upwards of 90 pounds and must be properly hoisted into a space that you need to cut out of a wall. Though it is possible to handle this on your own if you are more experienced, this type of installation might require 2 people. It's also very important to consider your air conditioning unit's proximity to an electrical outlet. It would be horrible to cut a big hole in your wall, only to realize that there is nowhere to plug your wall unit AC in once its installed.

Because of the extra features (such as a heat pump), wall unit air conditioners often use more energy than other types of comparable units. Make sure you purchase one with a high EER (energy efficiency rating) and, again, always make sure that your air conditioning unit is appropriately sized for the room you intend it to cool (figure 35BTU for each square foot).

Typical wall unit air conditioners usually cost between $500 - $800, which is, again, a bit more costly than standard window unit air conditioners.

For those looking for a more serious air conditioning unit who feel comfortable with the installation, wall unit AC's might be a great option.