If the system has gone years without service, fix safety items first, then electrical parts, then airflow, drainage and coils. That order protects your household first and the equipment second. The goal is a system that survives a Tucson summer, where airport normals show about 68 days a year at or above 100F.
What is the priority order?
| Order | Item | Why it comes first |
|---|---|---|
| 1 | Gas, combustion and carbon monoxide checks | Safety risk |
| 2 | Electrical connections and capacitor | Failing parts can trip breakers or damage the compressor |
| 3 | Filter and airflow | Cheapest fix, affects everything |
| 4 | Condensate drain and pan | A clog can leak and shut the system off |
| 5 | Indoor and outdoor coils | Dust cuts heat transfer |
| 6 | Refrigerant charge check | Low charge freezes coils and strains the compressor |
| 7 | Ducts | Leaks waste cooled air |
| 8 | Thermostat | Settings and calibration |
Why start with safety?
A furnace with a cracked heat exchanger or a bad gas valve is a risk, and a neglected combustion system can make carbon monoxide. If it hasn’t run since last winter, ask a pro to inspect it before the cold season. See carbon monoxide in a Tucson home.
What can I do myself?
Replace the filter, clear debris and cottonwood fluff from around the outdoor unit, and make sure the registers are open. Tucson’s dust loads filters quickly, so check them often. See filter guidance for Tucson dust and how to clean AC coils. Leave refrigerant, electrical parts and gas work to a licensed pro.
What does a pro add?
A pro can test the capacitor and contactor, clear the drain, clean coils properly, check the charge and look at the ducts. If your rooms are uneven, ask for a duct leak check. The EPA does not recommend routine duct cleaning on a fixed schedule, and it found little evidence that cleaning ducts alone improves efficiency.
TEP’s Efficient Home Program, as listed by TEP in October 2026, lists up to $160 total for an AC tune-up ($80 refrigerant charge repair, $40 indoor coil cleaning, $40 outdoor coil cleaning) through a participating contractor. Confirm eligibility with TEP before you book.
How do I keep it from happening again?
Set a maintenance schedule and keep the paperwork with your warranty, and read the warranty to see what records it asks for. See an HVAC maintenance schedule for Tucson and the pre-summer AC tune-up checklist.
When to call us
Climate Pros Tucson matches you with a licensed local pro for a catch-up visit. See AC tune-up, HVAC maintenance and the Tucson HVAC hub. Call (520) 353-2520 and we’ll match you with a licensed local pro.