Why do AC coils get dirty in Arizona?
AC coils get dirty in Arizona because dust, pollen, cottonwood fluff, leaves and monsoon debris collect on the outdoor coil, while airborne dust that passes the filter coats the indoor coil. A dirty coil cannot shed or absorb heat well, so the system works harder and cools less.
Dust storms and construction in growing parts of the West Valley add to the load. Outdoor units near landscaping, gravel or a dryer vent collect more.
A dirty condenser coil raises system pressures and temperatures, which stresses the compressor. Over a long cooling season that wear adds up, which is why coil cleaning is part of a good maintenance visit.
How do you clean the outdoor condenser coil step by step?
Turn off the thermostat and the outdoor disconnect, clear leaves and debris from around the unit, and brush loose dirt from the fins. Rinse from the inside out through the coil with a garden hose on gentle spray, apply coil cleaner if needed, let it soak as directed, and rinse again.
Rinsing from the inside out pushes dirt back the way it came in. Spraying only from outside can pack debris deeper into the coil. Keep the water gentle, and keep it away from the electrical compartment.
Take the top grille off only if you can do so safely and without disturbing the fan wiring. Bent fins can be combed straight with an inexpensive fin comb. Wait until the unit is dry before restoring power.
Can you clean the indoor evaporator coil yourself?
You generally should not clean the indoor evaporator coil yourself. It sits behind a sealed panel on or above the air handler, is easy to damage, and cleaning wrongly can leave water in the system or push debris into the drain. A technician has the tools and access to do it correctly.
Signs of a dirty evaporator coil include weak airflow, ice on the coil or lines, a musty smell and rising energy use. These can also point to a refrigerant problem, so a proper diagnosis is better than guessing.
A clogged condensate drain is a related issue. In summer, a blocked drain can overflow into the ceiling, so ask a technician to check it during service.
How often should AC coils be cleaned?
AC coils should be checked at least once a year, ideally before the cooling season, and cleaned when they show dirt buildup. Homes near dusty lots, construction or heavy landscaping may need more attention. A seasonal tune up lets a technician inspect both coils.
A quick visual check each month during summer is easy. If you can see a gray mat on the fins or the unit is running longer than usual, it is likely time.
Keep a couple of feet of clearance around the outdoor unit and replace the indoor filter on schedule. A clean filter keeps the evaporator coil cleaner for longer.
More questions: AC Maintenance: 12 Most Asked Questions Answered