When Houston air conditioners fail
Houston runs about 3,280 cooling degree days a year against roughly 1,220 heating degree days (NOAA normals, IECC climate zone 2A). Systems here work seven months and idle five. The calendar below is the pattern we see in the calls, not a forecast.
- AprilFirst 85°F humid week. Systems that sat since October start up and the first capacitor and contactor failures show. Cheapest month to get a tech out.
- June–JulyPeak. Heat index over 105°F, dew points in the 70s. Condensate drains clog, float switches trip, coils freeze on dirty filters. Same-day slots fill by noon.
- AugustCompressor month. Units that limped through June fail on the hottest afternoons. Refrigerant leaks that were marginal in May are empty now.
- SeptemberStorm season. Power flickers and surges after outages take out control boards and hard-start components. Water in the pan after a lightning-tripped float.
- October–MarchOff-season. Heat pump owners call about defrost steam and cool air in heat mode, most of which is normal. Good window for the leak repair you deferred.
Where in Houston
Contractors in this network run the whole Harris County footprint and the counties that grew into it. Inside Beltway 8 that means the Heights, Montrose, Bellaire and the Medical Center; Pasadena and Baytown on the east side; Cypress, Spring and The Woodlands up the 249 and I-45 corridors; Katy and the Energy Corridor west; Sugar Land and Missouri City in Fort Bend County; Pearland and League City south toward the bay.
The housing stock matters for repair. Katy, Cypress and Pearland subdivisions from the 2000s are hitting the 15–20 year mark where the original builder-grade condenser is on its second or third capacitor and first compressor conversation. Inside-the-loop bungalows and 1960s ranches in Bellaire and Spring Branch often run closet air handlers with long, poorly sloped condensate lines — the number one Houston leak. Townhomes in Montrose and the Heights put the air handler in the attic, where a clogged drain means a ceiling stain before anyone notices.
The Houston failure modes
- Condensate drain clog
- The dominant Houston call. Algae grows in the drain line all summer in this humidity; the pan fills; the float switch cuts power and the system reads as "dead." A wet/dry vac on the outdoor PVC stub clears most of them. If the line was never treated or the pan has no float switch, it shows up as water on the floor or through a ceiling instead.
- Frozen evaporator coil
- High latent load plus a filter that went four months without a change. The coil ices, airflow drops to nothing, the house creeps up to 82°F with the unit running flat out. Off, FAN only for two to four hours, new filter, then a tech — a coil that ices again within the hour with a clean filter is low on charge.
- Capacitor and contactor
- Sustained 95°F ambient plus seven months of daily cycling. Outdoor unit hums and the fan does not spin, or it clicks and does not start. The most common under-$400 fix in the metro.
- Corrosion on the outdoor coil
- Gulf air east of downtown and near Galveston Bay — Pasadena, Baytown, League City — eats aluminum fins and copper connections faster than the inland suburbs. Leaks at brazed joints on 8-plus-year-old condensers are common there.
Permits and licensing in Houston
Repairs do not need a permit. A replacement of the condenser, coil or air handler inside the City of Houston needs a mechanical permit issued through the Houston Permitting Center, which licensed contractors pull online. Katy, Sugar Land, Pearland, League City and The Woodlands run their own building departments; unincorporated Harris County work goes through the county.
Anyone who works on your refrigerant circuit in Texas must hold a license from the Texas Department of Licensing and Regulation, Air Conditioning and Refrigeration program. The license number is searchable on that site; ask for it before the tech opens the panel.
CenterPoint incentives
CenterPoint Energy is the electric delivery company for most of Harris County. Its residential HVAC program pays incentives on the installation invoice when you use a participating contractor: incentives start at $200 for equipment at 15.2 SEER2 or better (the Texas minimum is 14.0), covering central AC, heat pumps and mini-splits. CenterPoint also runs an A/C tune-up offer for operational systems at least a year old, single-family only. Details on the CenterPoint Energy efficiency page.
None of this applies to a repair — it becomes relevant the moment the quote turns into a replacement conversation. The federal 25C tax credit ended for equipment placed in service after 2025 and is not on the table for a 2026 install.
What AC repair costs in Houston
Houston labor runs at the lower end of the five-metro range. Parts are national. Typical ranges, diagnostic usually credited toward the repair:
| Repair | What it involves | Houston range |
|---|---|---|
| Diagnostic visit | Pressures, split, capacitor, electrical. Same-day in July usually carries a premium. | $75–$140 |
| Condensate drain clear + treat | Vacuum, flush, algaecide, float switch check | $90–$220 |
| Run capacitor | Part and labor, outdoor unit | $140–$350 |
| Contactor | Pitted or welded contacts | $140–$320 |
| Condenser fan motor | Motor, capacitor, blade balance | $300–$650 |
| Leak repair + recharge | Electronic leak search, braze, evacuate, charge by subcooling. R-410A price drives the top of the range. | $400–$1,400 |
| Evaporator coil replacement | Coil, line set flush, new drier | $1,100–$2,400 |
| Compressor | Usually a replace-the-condenser conversation past 10 years | $1,400–$2,800 |
If the quote lands in the last two rows on a unit over twelve years old, read what a replacement costs in Houston and what CenterPoint pays toward it before you decide. Symptom-by-symptom causes for any metro are on the AC repair page. Local weather context: National Weather Service Houston/Galveston.