Phoenix Home Answers

What AC maintenance should I do each month in Phoenix?

A national AC maintenance checklist assumes a short summer. Phoenix doesn’t have one. The air conditioner here starts working hard in spring, runs through a long stretch of triple-digit heat, then faces months of monsoon dust before it gets a break. The work itself is simple; what changes in Phoenix is the timing.

Why Phoenix needs its own schedule

The National Weather Service’s 1991–2020 averages for Phoenix put the first 100°F day on May 2 and the last on October 5. The first 110°F day arrives on average June 11, and the last on August 26. That’s about five months of heavy cooling, and an air conditioner in constant use needs more attention than one that cycles on a few afternoons a week.

Then there’s the monsoon, which the NWS says officially runs from June 15 through September 30. Storm outflows can push winds of 50 mph or more and raise walls of dust miles across. The Department of Energy notes that filters need more frequent attention in dusty conditions, and that outdoor condenser coils can get very dirty when the air around them is dusty.

A month-by-month AC maintenance checklist for Phoenix

When What to do Why it matters in Phoenix
January–February Check the filter once a month. Change it if it looks dirty. ENERGY STAR says to change the filter at least every 3 months, even in light-use months.
March–April Book a professional cooling checkup. Clear plants and debris at least 2 feet back from the outdoor unit. ENERGY STAR recommends a spring cooling check because contractors get busy once summer comes. The first 100°F day averages May 2.
May Put in a fresh filter by the start of May, before heavy use starts. DOE says to clean or replace filters every month or two during the cooling season.
June–August Check the filter every month and replace it as needed. Look at the outdoor unit for dirt and debris. 110°F days average June 11 through August 26, so the system runs longer.
June 15–September 30 (monsoon) Check the filter and the area around the outdoor unit after each dust storm. Monsoon outflows can carry walls of dust miles across.
September–October Keep checking the filter monthly until the heat breaks. The last 100°F day averages October 5.
November–December Replace the filter at the end of the cooling season. Heat pump owners can book the heating check in fall. ENERGY STAR recommends checking heating systems in the fall.

What you can do yourself each month

Most of the checklist is filter work and a quick look outside. It takes a few minutes:

  • Check the filter. ENERGY STAR says to inspect it every month and change it if it looks dirty after a month. The Department of Energy says replacing a dirty, clogged filter can cut an air conditioner’s energy use by 5% to 15%. For more on timing, see how often to change your AC filter in Phoenix.
  • Keep the outdoor unit clear. DOE recommends trimming plants back at least 2 feet so air can move around the condenser, and notes that dryer vents, falling leaves, and lawn mowers are all sources of dirt and debris.
  • Watch the condensate drain. ENERGY STAR notes that a plugged drain can cause water damage in the house and affect indoor humidity. If you see water where it shouldn’t be, have it checked.

Before storm season starts, walk through a monsoon AC prep checklist so the unit and the yard around it are ready for wind and dust.

What a professional checkup covers

Some maintenance is not homeowner work. ENERGY STAR and the Department of Energy list these tasks for a technician:

  • Checking the refrigerant charge and testing for leaks
  • Cleaning the evaporator and condenser coils (DOE says to check the evaporator coil every year)
  • Tightening electrical connections and measuring voltage and current
  • Lubricating moving parts
  • Checking the system’s controls, operation cycle, and thermostat accuracy
  • Inspecting the condensate drain

Spring is the time to book it. A checkup in March or April, before the first 100°F day, gives you room to fix a problem while you can still wait for a regular appointment. Between visits, keep up the monthly filter check. The Department of Energy calls filter replacement the most important maintenance task for efficiency, and ENERGY STAR notes that a dirty filter can damage equipment and lead to early failure.

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