Window AC Units

Choosing the right size room air conditioner relies mainly on the size of the room itself, measured in square feet. To find this, use a tape measure to obtain the length and width of the space you're cooling. Then multiply these dimensions. You should size an AC unit using this figure and also the shape of your room as a guide. By doing so, you'll eliminate the first and most common mistake of either undersizing or oversizing a unit—often done in fear of both potential wasted energy and inadequate cooling.

For your window air conditioning unit to perform at its best, it cannot go without maintenance for too long. Every month, during the times of year when you are most likely to use it, you should wipe down the interior and exterior of the unit. I recommend using a damp cloth. A thorough wipe-down every month should keep dust and debris from accumulating too much inside and outside the unit. Meanwhile, the air filter should receive more attention. You should clean or replace it every 30 to 60 days, depending on how much you are using the unit.

Your window air conditioning unit may require professional intervention if certain indicators are present. Noises that are unusual for the unit, such as grinding, buzzing, or rattling, can point to internal mechanical difficulties. If the unit is not cooling to its typical level or if it is not cooling evenly, you might have a refrigerant leak or a compressor problem. Water leakage, excessive frost, or a unit that has suddenly developed a habit of cycling on and off are other signs that you are in need of repair or close maintenance.

To improve energy efficiency, the first step is to make sure the air conditioner is properly installed and that there is a tight seal around the unit. If you need to use it, apply weatherstripping or foam insulation to prevent air from leaking around the edges. Next, make sure that the thermostat is set to a mid-range temperature. If your unit has an energy-saving setting, use that. Also, consider using ceiling or portable fans to push the cooled air around; this will let you set the A/C to a higher temperature while still feeling comfortable.

Homeowners with basic do-it-yourself skills can install most window air conditioners. The key to a successful installation is to take careful measurements of the window opening and the air conditioner itself. The unit must be compatible with the window opening, and the opening must be sufficiently clear for the unit to fit. Beyond that, the installation is straightforward: secure the mounting brackets, set the unit in the window, and ensure that it is level and airtight. If that process sounds difficult or if your window has an unusual configuration, professional installation is a good option.

A window air conditioning unit that is well taken care of can last a good long while. The average lifespan really is around 8 to 10 years, which is the same for almost any air conditioning unit. But if you're using it in an area where the outdoor temperatures are extreme or the level of humidity is high (or both) and if you are not maintaining it very well, you're probably going to get a shorter lifespan out of it. Conversely, if you are regular and thorough with the cleaning, professional and timely with what servicing and repairs it needs, and if you catch and get those minor problems fixed as soon as they are noticed, you are (in theory) extending its lifespan.

Air conditioners installed in windows tend to be more powerful than the types of air conditioners you can easily move from room to room. That said, there are several reasons why you might opt for a portable air conditioner rather than a window unit. In some cases, portability is the primary concern. If you can't install a window unit because your windows don't accommodate one, or because you're in a situation where you can't make a permanent installation — like in a rental — then you're left with using either a portable AC or going without a more affordable and convenient option than the central AC unit that some rentals have.

To avert the appearance of mold, one must engage in consistent upkeep and, most importantly, control moisture. Proper drainage is imperative. The insides of the unit must be kept impeccably clean and dry, even when the unit itself is not in operation. To this end, I recommend a periodic deep clean using a simple solution of water and white vinegar. It's an excellent way to assure that no mold is "in progress". If the unit is going to be stored for any amount of time, make sure that the storage location is dry and use a cover to keep the unit moisture-free.

Today, some window air conditioning units are equipped with a heat pump function that enables the unit to provide both heating and cooling. These dual-function units can be a more energy-efficient alternative to space heaters. However, models vary, and not all window AC units are built with this ability. So, check the specs of any unit you're considering to make sure it can heat as well as cool. And if you're looking to heat your home consistently throughout the winter, an AC with heat pump function isn't your best bet.

Start by examining the power supply to the unit. Make certain that it is actually plugged in and that the circuit breaker has not tripped. Then check the thermostat and make certain that the settings are appropriate for the type of climate in which you live—it might be time to re-calibrate the unit. If it still refuses to blow cold air, see if you can clean the filter. If it looks dirty, it probably is. Either replace it or wash it thoroughly; an obstruction in airflow could easily impede cooling.