What's on a central AC maintenance checklist?
Updated August 2026
The full central-AC routine is a fresh filter each month in cooling season, a coil rinse and condensate flush once a year, and one $75–200 pro tune-up every spring that reads the refrigerant charge. Stay on that and the system runs its full 12 to 15 years instead of stalling on a hot July afternoon. Nearly every summer breakdown traces back to a skipped filter or a coil no one ever hosed off.
| Task | Interval | Effort |
|---|---|---|
| Check or change the air filter | Monthly | 2 min · DIY |
| Glance at the outdoor unit for debris and weeds | Monthly | 2 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Hose the outdoor condenser coils clean | Yearly | 30 min · DIY |
| Flush the condensate drain line | Yearly | 15 min · DIY |
| Clear 2 feet of space around the condenser | Yearly | 15 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Check refrigerant charge and electrical | Yearly | $75–200 pro |
| Test capacitor, contactor, and temperature split | Yearly | incl. in tune-up |
| Task | Interval | Effort |
|---|---|---|
| Straighten bent condenser fins with a fin comb | As needed | 20 min · DIY |
What neglect costs
A clogged filter chokes airflow until the evaporator coil freezes into a block of ice, and thawing it plus the diagnosis is a $200–600 service call. Let the outdoor coils cake over and the compressor runs hot against high head pressure; a failed compressor is often $1,500–2,800, enough to justify replacing the whole unit. Low refrigerant from an unaddressed leak drags efficiency down and can burn out that same compressor. A ten-dollar filter and a spring rinse head off nearly all of it.
Leave these to a pro
The annual tune-up ($75–200, cheaper on a spring or maintenance-plan schedule) is the one job to hire out: only a tech with gauges can read the refrigerant charge and spot a slow leak before it strands you. Adding refrigerant is not a DIY item either, since it is an EPA-regulated gas and overcharging is as damaging as running low. Testing the run capacitor and contactor, the two parts that fail most, is also faster for someone who does it daily.
This whole checklist ships as reminders in OnOtto: every task above, on the right schedule for your home, snooze-proof.
Load this checklist as remindersFrequently asked questions
How often should I change the AC filter?
Check a 1-inch filter every month during cooling season and change it when it looks gray, which is usually every 30 to 60 days with pets or allergies and every 90 for a thicker pleated filter. A starved filter is the number-one cause of a frozen coil and a no-cool call, so it is the cheapest habit with the biggest payoff. See the pre-summer test routine for the full spring startup.
Can I clean the outdoor AC coils myself?
Yes. Kill power at the disconnect, clear leaves and grass off the fins, then spray the coils from the inside out with a garden hose (never a pressure washer, which bends the fins flat). A can of coil cleaner helps with greasy buildup. Fifteen minutes once a year restores the airflow the compressor depends on. Keep shrubs and the fence at least 2 feet back so the unit can breathe.
How do I know if my AC is low on refrigerant?
Warm air from the vents, ice on the copper line at the outdoor unit, a hissing sound, and a cooling bill creeping up are the tells. Low charge almost always means a leak, not normal consumption, so topping it off without finding the leak just delays the next failure. Have a tech pressure-test and repair the leak rather than pouring refrigerant into a system that will lose it again.
When is it time to replace the AC instead of repairing it?
Past 12 years, on old R-22 refrigerant, or facing a compressor or coil repair over about $1,500, replacement usually wins, since a new unit can cut cooling costs 20 to 40% and resets the warranty. Under 10 years with a cheap part failure, repair it. The replacement-timing guide walks the full math.