What Happens During an AC Tune-Up (and What a Good One Includes)

Published October 16, 2026 · Reviewed October 16, 2026

Part of our AC Maintenance & Tune-Up guides.

What is an AC tune-up?

An AC tune-up is a scheduled inspection, cleaning and measurement visit that checks whether a central air conditioner is clean, electrically sound, correctly charged and draining properly before it has to carry a full cooling season. It is not a repair visit. The goal is to find worn parts and dirty surfaces while they are still cheap to deal with, and to record baseline readings so the next visit can spot change.

ENERGY STAR recommends annual pre-season check-ups and says it is best to check the cooling system in the spring. In Greater Houston, where the air conditioner does most of the work for most of the year, that spring visit matters more than it does in milder climates.

A tune-up is only as good as the measurements behind it: a technician who cleans but does not measure has done half the job.

What does a good AC tune-up include?

A good AC tune-up covers five areas: the outdoor unit, the indoor coil and blower, the electrical components, the refrigerant circuit and the condensate drain. The ENERGY STAR maintenance checklist lists the core contractor tasks, and the list below groups them the way a technician usually works through a home.

Outdoor unit (condenser)

• Clean the condenser coil so it can shed heat; a dirty coil makes the compressor work harder.
• Check the condenser fan motor and blade for wear, wobble or noise.
• Clear debris, grass clippings and leaves from the cabinet and the space around it.

Indoor unit (air handler or furnace)

• Inspect and, where accessible, clean the evaporator coil.
• Clean and adjust blower components so the system moves the right amount of air.
• Check or replace the air filter and confirm it is the right size and direction.

Electrical components

• Tighten electrical connections and measure voltage and current on motors.
• Test the run capacitor against its rated value and look for bulging or leaking.
• Inspect the contactor for pitted or burned contacts.

Refrigerant circuit

• Check the refrigerant charge by measurement and adjust only if needed. Under EPA Section 608, technicians who maintain, service or repair equipment that could release certain refrigerants must be certified.
• Look for oil stains or other signs of a leak at joints and valves.

Drain and controls

• Check and clear the condensate drain line and pan, and test any float (overflow) switch.
• Check thermostat settings and system controls for proper and safe operation.

When should Houston homeowners schedule an AC tune-up?

Houston homeowners should schedule an AC tune-up in early spring, before the long run of 90-degree days begins. NOAA's 1991–2020 normals for Houston Intercontinental Airport (IAH) show average highs of 94.5°F in July and 94.9°F in August, about 111 days a year at or above 90°F, and roughly 3,288 cooling degree days against 1,266 heating degree days. In plain terms, a Houston air conditioner faces about 2.6 times as much cooling demand as the heating system faces heating demand.

Timing also matters for the grid. ERCOT set an all-time peak of 91.1 gigawatts on July 22, 2026, according to the U.S. Energy Information Administration. A system that fails in a heat wave fails when every contractor in the region is busiest.

Homes with a heat pump need a second look in the fall, because the same outdoor unit also heats. See the heat pump maintenance checklist for Houston for the heating-mode items.

What goes wrong when an AC skips its tune-up?

An AC that skips its tune-up usually fails in one of a few predictable ways, and most of them start small. ENERGY STAR notes that dirty coils and dirty filters raise energy costs and shorten equipment life.

• Dirty coils: a dirty condenser coil raises operating pressure and heat on the compressor; a dirty evaporator coil cuts airflow and can freeze.
• Clogged condensate drain: Houston's humidity produces a lot of condensate. A blocked line can back up into the pan, trip the float switch and shut the system off, or overflow into a ceiling. Our blog covers how to fix a clogged AC drain line.
• Weak capacitor or worn contactor: these are common summer no-cool calls. A capacitor that is drifting out of range can be caught on a meter before it stops the outdoor unit.
• Low refrigerant: refrigerant is not consumed. If the charge is low, there is a leak somewhere. A good tune-up flags it rather than quietly adding refrigerant every year. For the symptoms, read how to know if your AC is low on Freon.

How can you tell whether a tune-up was thorough?

You can tell a tune-up was thorough when the technician leaves you written measurements, not just a checked box. Ask for these, and keep them with your equipment records:

1. Capacitor readings compared with the rated value printed on the part.
2. Voltage and amperage readings for the compressor and fan motors.
3. Refrigerant readings and the method used to judge the charge, plus a note of the refrigerant type on the nameplate (R-22, R-410A, R-32 or R-454B).
4. Filter size and condition, and whether it was replaced.
5. Condition of the condensate drain and whether the float switch was tested.
6. Before-and-after photos of the outdoor coil, if you can't see it yourself.

Two things are worth questioning: refrigerant added with no mention of a leak, and a long list of urgent replacements with no readings to support it. Year-over-year numbers are the most useful proof you can have, because they show a part trending toward failure.

What can you safely do between tune-ups?

Between tune-ups, a homeowner can safely handle the filter, the space around the outdoor unit, the thermostat and a visual check of the drain. ENERGY STAR recommends inspecting, cleaning or changing filters once a month.

• Check the filter monthly during the cooling season and replace it when it looks loaded.
• Keep plants, fencing and stored items clear of the outdoor unit, and rinse away grass clippings after mowing.
• Look at the condensate pan or drain outlet for standing water.
• Confirm the thermostat has power and is set to cool; our blog explains how to tell if your thermostat has power.

Leave refrigerant, capacitors, contactors, wiring and anything behind a service panel to a licensed technician. Those parts carry stored electrical energy or regulated refrigerant, and a mistake there costs more than the visit.

Are there free tune-up programs or maintenance plans in Houston?

CenterPoint Energy offers a free ComfortCheck A/C tune-up to eligible residential customers in its Houston Electric service area, delivered through participating contractors. As of October 2026, CenterPoint lists these conditions: the central AC or heat pump is at least one year old and working, the home has not had a program tune-up in the past five years, and apartments are excluded. Parts of The Woodlands are served by Entergy Texas rather than CenterPoint, so check which utility serves your address. Program rules change, so confirm current eligibility on CenterPoint's site.

Many contractors also sell annual maintenance plans. The JHC Cooling & Heating plan, for example, covers "cleaning condenser coils, cleaning evaporator coils (if accessible), maintenance checks, checking electrical components, air handlers and furnaces," applies to residential systems only, and comes with "No trip fee for repairs when you sign up for the maintenance plan for one year." Whatever plan you compare, hold it to the checklist above.

Frequently Asked Questions

How often should an AC get a tune-up in Houston?

Once a year is the standard recommendation, and ENERGY STAR says the cooling system is best checked in the spring. Houston averages about 111 days a year at or above 90°F at IAH, so a spring visit catches problems before the heaviest load. Heat pumps benefit from a second visit in the fall because they also heat.

Does an AC tune-up include adding refrigerant?

A tune-up includes checking the refrigerant charge by measurement, not automatically adding refrigerant. Refrigerant is not used up, so a low charge means there is a leak. A thorough technician reports the leak instead of topping off the system every year.

Can I do my own AC tune-up?

You can handle the homeowner tasks: checking the filter monthly, keeping the outdoor unit clear, watching the condensate drain and checking the thermostat. Electrical parts like capacitors and contactors, and anything involving refrigerant, need a licensed technician. EPA rules require certification to service equipment that could release certain refrigerants.

Is CenterPoint's ComfortCheck AC tune-up really free?

CenterPoint Energy describes the ComfortCheck A/C tune-up as free for eligible residential customers in its Houston Electric service area, performed by participating contractors. As of October 2026 the system must be at least a year old and working, with no program tune-up in the past five years, and apartments are excluded. Confirm current rules on CenterPoint's website before scheduling.

Will a tune-up prevent my AC from breaking down?

A tune-up lowers the chance of a mid-summer breakdown but it cannot rule one out. Its real value is catching weak capacitors, worn contactors, clogged drains and dirty coils early, and recording readings that show a part trending toward failure.

What should I get in writing after a tune-up?

Ask for capacitor readings, motor voltage and amperage, refrigerant readings with the refrigerant type, filter size and condition, and the state of the condensate drain and float switch. Keeping these each year lets you compare numbers and spot a declining part.

Sources

1. ENERGY STAR — Maintenance Checklist — contractor tune-up tasks, spring timing for cooling, monthly filter checks (as of October 16, 2026)
2. U.S. EPA — Section 608 Technician Certification — certification requirement for technicians who service refrigerant-containing equipment (as of October 16, 2026)
3. NOAA NCEI — U.S. Climate Normals 1991–2020, Houston Intercontinental (USW00012960) — July/August normal highs, days at or above 90°F, cooling and heating degree days (as of October 16, 2026)
4. U.S. EIA — Today in Energy (August 3, 2026) — ERCOT all-time peak of 91.1 GW on July 22, 2026 (as of October 16, 2026)
5. CenterPoint Energy — Heating & Cooling programs (ComfortCheck A/C Tune-Up) — free tune-up eligibility conditions (as of October 16, 2026)
6. The Woodlands Township — Utilities — Entergy Texas and CenterPoint service split in The Woodlands (as of October 16, 2026)