Condenser coils are located on the outside of your house; thus, they are subject to everything that Mother Nature can throw their way. If you do nothing to protect them, they will never function as efficiently as they could. Luckily, you do not need a degree in thermodynamics in order to take steps to improve the function of your coils.
Throw Some Shade
Coils that are exposed to direct sunlight will absorb the sun's energy and heat up. Furthermore, the hotter it gets outside, the harder your coils have to work to cool the refrigerant running through them. Planting a tree to shade your coils can help in two ways. First, the tree will block sunlight before it has a chance to heat up your coils, and second, trees are constantly engaging in a process called evapotranspiration through which they release water vapor into the surrounding air. This water vapor absorbs heat from the air, and the air thus cooled will settle into your yard. By these two processes, trees can reduce your cooling costs by up to 18%.
Condenser coils use a fan to push air over fins that contain refrigerant. Thus, they depend on airflow in order to cool the refrigerant and thus convert it back to a liquid. If shrubs, flowers, grass, or other plants grow too close to your coils, they can obstruct airflow and prevent the coils from doing their job properly. To save yourself work and prevent plants from growing up inside the coils, you should place plants on a plastic or cement pad. You should also lay down weed mat for the first few feet around your coils so that plants do not encroach on them.
Keep Coils Clean
Even if you keep plants away from your coils, they can still get choked with yard debris such as dandelion fluff, dust, and dead leaves. In fact, dirty coils can reduce your overall efficiency by up to 30%. You can clean your coils with a stiff bristle brush and then rinse them with water from a hose. Inspect your coils at least once a month, especially during the spring and fall, to make sure they stay clean.
The tasks described above are not super technical or complicated, yet they can have an impressive impact on how your coils function. Remember that your coils are responsible for cooling super-heated refrigerant coming from your evaporator coils and cooling it so that it can convert back to a liquid state. To accomplish this, coils need access to the coolest air possible and plenty of airflow. Thus, anything you can do to cool the air around your coils and improve airflow will help you to keep your cooling costs as low as possible.
For more information or for help with your unit, contact a company that does air-conditioning repair in your area.