Window-mounted air conditioners are extremely useful devices, providing efficient cooling power during the hottest summer months at a fraction of the price of a full-blown ducted air conditioning system. However, window air conditioners are as vulnerable to occasional mechanical malfunctions as any other kind of air conditioning system, and one of the most commonly encountered problems is ice buildup.

A few spots of ice accumulating around the edges of your window air conditioner's vent generally aren't much to be worried about, but more significant freezing problems can be a more serious matter. Excess solid ice inside your air conditioner can damage moving parts, reduce the cooling efficiency of your system and cause fan motors to burn out more quickly.

Fortunately, most problems that cause freezing problems in window air conditioners can be repaired swiftly and inexpensively by air conditioner repair services. The following problems can all cause excessive ice buildup in a window-mounted air conditioner, and should be tended to by a air conditioner repair company as soon as possible:

Insufficient or contaminated refrigerant

The liquid refrigerant that runs through your window air conditioner is one of its most vital components, as this liquid absorbs heat from the air as it passes over the conditioner's cooling vane. If your air conditioner does not have enough refrigerant, or the refrigerant is contaminated with trapped air bubbles or water, the liquid refrigerant will expand too rapidly as it evaporated from a liquid to a gas, causing excessively cold temperatures that freeze the water vapour suspended in the air and cause ice to accumulate on the cooling vanes and other components.

Low levels of refrigerant and refrigerant contamination are generally caused by leaks in your air conditioner's refrigerant pipes, and in many cases simply topping up or exchanging the fluid will not be enough to solve the problem. Have an air conditioning repair service inspect your air conditioner to find any leaks in your pipes; these leaks can usually be repaired quickly without the need for replacement parts.

Dirty air filters

The air passing through your window air conditioner will also become to cold if it passes over the cooling vanes too slowly, a problem commonly caused by dirty air filters that reduce the rate of airflow. Solid detritus and dirt deposits can buildup on these filters over time, blocking proper air flow.

Cleaning and/or replacing your window air conditioners dirty air filters is a relatively simple task, and you can attempt to perform this task your self if you are reasonably familiar with basic air conditioner maintenance. You should call in professional help if you are at all unsure about cleaning your filters yourself, as improper cleaning practises can damage your air filters and other nearby components.

Damaged blower fans

In some cases, insufficient air flow that causes freezing is not caused by dirty air filters, but by problems with the fan that blows the air through the filters. If your air conditioner is reasonably old, simple wear and tear may have caused your fan to slip out of alignment and lose efficient. Solid matter entering the fan housing and damaging the fan blades can also cause problems. If low airflow is causing freezing problems, but your air filters have been ruled out as the culprit, your blow fan will need to be professionally inspected, repaired or replaced.