The air condenser fins, also called condenser coils, do an important job in the air conditioner — they help move hot air out of the AC so proper cooling can occur. Over time, damage to the fins can lead to problems.
Damaged fins can affect airflow into the AC unit. Although minor damage usually has no symptoms, more extensive damage will affect airflow to the point that the AC won't have the air circulation force that it displayed before the damage. There may be weak airflow through the vents in the home, which in turn means it will take longer to cool the home to the desired temperature.
The restricted airflow may also affect efficiency. You may notice that the AC is running for longer periods of time and that your energy bills are going up even though temperatures and usage patterns remain the same. Damaged fins also put stress on the unit due to prolonged operation times, which can lead to overheating or breakdowns.
Part of the reason that the fins become damaged is that they are relatively exposed to the outdoors. Damage is often a result of landscaping and gardening practices. Hitting the AC unit with a lawnmower, string trimmer, or other tools can lead to bent and damaged fins. Care should always be exercised when doing work around the AC. The best solution is to make sure no grass or plants grow near the unit.
Dirt is another common cause of fin problems. Install a barrier so pets, like your dog, can't reach the unit. Dog urination on the fins can lead to rust and corrosion. Mud, pollen, and other debris can also coat the fins so that they don't work as well. Installing a gravel buffer around the AC can prevent mud and debris from splashing onto the fins when it rains.
Repairs and Solutions
Fortunately, most fin damage is reversible. Bent fins are repaired with the help of a fin comb, an inexpensive tool that is combed through the fins in order to straighten them. Even badly bent fins can typically be straightened successfully.
If the fins are simply dirty, you can spray them down with a hose to clean them. More stubborn dirt can be gently scrubbed off with a soft bristle brush. Corrosion and rust can't be fixed, though. You will need to replace the condenser fin assembly if there is corrosion present.
Contact an air conditioning repair technician for more help.