Possible Reasons Why Your Window Air Conditioner Isn't Cooling (And Fixes To Try)

During the warmer months, a window air conditioner can help keep your room comfortable for work, sleep, and relaxation. However, sometimes, it can fail to work as expected and leave you scratching your head. A common issue is when the AC turns on but doesn't blow cold air. So, why does that happen, and more importantly, what can you do to fix it? 

Of course, the first thing to do in such situations is to check the thermostat settings and ensure the set temperature isn't too high. If you've already done that, your next step is to ensure the AC's air filter isn't clogged. This filter is typically located near the indoor air handler unit and is responsible for trapping dust, dirt, and other particles. As the AC pulls in air from the room to pass over the cooling coil, the filter ensures only clean air enters the unit so that the internal components stay clean and operate efficiently. However, over time, the air filter can get clogged, which may end up restricting the airflow and prevent cold air from circulating.

Thankfully, cleaning the air filter is something you can do yourself. Start by turning off the AC and removing the front panel to access the air filter. Next, use a handheld vacuum cleaner to get rid of any loose dust and debris, then wash the air filter with soapy water. Finally, let the filter dry completely before installing it back in.

Just like the air filter, your AC's condenser unit, which is located on the back, can also become blocked due to dust and debris. This can not only prevent your AC from running efficiently but also affect its ability to blow cold air. To fix this, you can try cleaning the outer casing and the condenser coil. 

Another reason why your AC may not blow cool air is if there's a problem with its fan. If your AC is making unusual noises like buzzing, you should inspect the fan blades and motor. Open the unit's housing to check if the fan is loose or bent out of shape. While you're at it, clean off any dust or dirt on the fan blades using a vacuum. If the fan is not functioning at all while your AC is running, you may need to replace the fan motor or fan belt. 

You may have noticed your AC automatically turns off once the room reaches the temperature set on the thermostat, and then turns back on once the temperature rises again. It does this with the help of a device called a thermistor, which is usually located behind the air filter. It monitors the air around the evaporator and signals the system to turn on or off as needed. If the thermistor is faulty, it's fairly straightforward to replace it yourself with the help of the user manual and the right AC maintenance tools.

If your AC's components seem to be in good shape, there may be a problem with the control panel. It is an important component that is responsible for sending instructions to each part of the AC unit, telling them when and how to operate. Similarly, a faulty compressor can also cause your AC to malfunction. While it's technically possible to fix problems with the control panel and the compressor yourself, it's far more complicated than cleaning an air filter or fan blades. In such cases, your best option is to contact a technician. 

Your window AC may also fail to cool due to low refrigerant levels. Refrigerant is a fluid that flows through the AC coils and removes heat from the air. If your AC has gradually stopped cooling, it may indicate a refrigerant leak. In some cases, you might also notice ice buildup on the condenser. In this case, it's best to contact a technician, who can inspect the unit for leaks and handle the repair.

Keep in mind that while contacting a technician will likely resolve most issues with the AC, the repair cost can range anywhere from $60 to $250 on average, depending on the problem. If your unit is already old, it may make more sense to buy a new one from a reputable AC brand.