You notice the pattern mid-afternoon when the Texas heat is at its worst: your air conditioner kicks on, runs for five or ten minutes, shuts off, then fires back up again a few minutes later. The house never quite reaches the temperature on the thermostat. Your energy bill climbs. And that compressor is working twice as hard for half the result.
This is short cycling — one of the most common and most damaging AC problems in the Gulf Coast region. The compressor starts and stops repeatedly without completing a full cooling cycle, and every time it does, it wastes energy, generates unnecessary wear, and moves you closer to a premature system failure.
Here are the five most common causes of short cycling and what you can do about each one.
1. A Dirty or Clogged Air Filter
This is the simplest cause — and the one most homeowners overlook.
When your air filter is clogged with dust, pet hair, and debris, it restricts airflow across the evaporator coil. The coil can't absorb heat efficiently, internal pressures build abnormally, and the system's safety controls shut the compressor down to prevent damage. A few minutes later, pressures equalize and the system tries again — only to hit the same wall.
In the League City and Friendswood area, air filters get dirty faster than the standard 90-day recommendation suggests. Construction activity in growing neighborhoods like Bay Colony sends fine particulate into the air. Pollen seasons run nearly year-round. Pet owners may need to change filters every 3-4 weeks during peak cooling season.
What to do: Check your filter right now. If you can't see light through it when held up to a window, it's too dirty. Replace it and monitor whether the short cycling stops within a few hours.
Pro Tip: During the peak cooling months of June through September, check your filter every two weeks. A clean filter is the single cheapest thing you can do to protect your AC system and maintain efficiency. Set a phone reminder — it takes 30 seconds and can prevent hundreds of dollars in repairs.
2. A Frozen Evaporator Coil
This one seems counterintuitive — how can anything freeze when it's 100°F outside? But a frozen evaporator coil is extremely common on the Gulf Coast, and it's often a downstream consequence of the dirty filter we just discussed.
When airflow is restricted (from a dirty filter, closed vents, or a failing blower motor), the evaporator coil gets too cold. Moisture from the humid Gulf Coast air condenses on the coil and freezes into a layer of ice. That ice further restricts airflow, accelerating the freeze. The system detects abnormal pressures or temperatures and shuts down. The ice begins to melt, pressures normalize, the system restarts — and the cycle repeats.
You can sometimes spot a frozen coil by checking the refrigerant lines at your outdoor unit. If the larger copper line (the suction line) is coated in ice or heavy frost, the evaporator coil is likely frozen.
What to do: Turn the system to "fan only" mode for 2-3 hours to let the coil thaw completely. Check and replace the air filter. If the coil freezes again after thawing, the problem goes deeper — possibly low refrigerant or a blower motor issue — and you'll need professional diagnosis.
3. An Oversized AC Unit
This is the cause that frustrates homeowners most because it means the system was wrong from the day it was installed.
An oversized air conditioner cools the air near the thermostat quickly — sometimes in just a few minutes — and then shuts off. But it hasn't run long enough to dehumidify the air or distribute cooling evenly throughout the house. Rooms far from the thermostat stay warm. Humidity stays high. The thermostat temperature rises quickly, and the system fires up again.
Oversizing is surprisingly common in new construction. Builders sometimes install larger units as a perceived selling point, or contractors use rule-of-thumb sizing instead of performing proper Manual J load calculations. In rapidly developed neighborhoods like Wedgewood Village in Friendswood, where homes went up quickly during building booms, oversized systems are something we see regularly.
What to do: If your system is less than 5 years old and has always short-cycled, oversizing is a strong possibility. A qualified technician can perform a load calculation on your home and compare it to your installed equipment capacity. If the unit is significantly oversized, the long-term solution is replacement with a properly sized system. In the meantime, strategies like adjusting fan speed or adding zone dampers can sometimes mitigate the problem.
When to Call a Pro: If your AC was recently installed and has short-cycled from day one, don't wait. An oversized unit running in short cycles will fail years before its rated lifespan. The compressor endures its heaviest electrical and mechanical stress during startup — a system that starts 15-20 times per hour wears exponentially faster than one running proper 15-20 minute cycles.
4. A Failing Compressor
The compressor is the heart of your AC system — the component that pressurizes refrigerant and drives the entire cooling cycle. When a compressor begins to fail, it often manifests as short cycling before it dies completely.
A failing compressor may overheat internally and trigger its thermal overload switch, shutting the system down until it cools. It may draw excessive amperage, tripping the circuit breaker or contactor. Or it may lose compression on one or more cylinders, unable to build sufficient pressure to sustain the cooling cycle.
Compressor failure is most common in systems over 10 years old, but it can happen sooner in our climate. The Texas Gulf Coast demands more from air conditioning compressors than nearly any other region in the country — systems here run 2,500-3,000+ hours per year compared to 1,000-1,500 hours in northern states.
What to do: Compressor diagnosis requires professional equipment and expertise. A technician will check amperage draw, compression ratios, and internal temperatures. If the compressor is failing, you'll need to weigh the cost of compressor replacement (often $1,500-$2,500 including refrigerant and labor) against the age of the overall system. On units over 12 years old, full system replacement is usually the smarter financial decision.
5. A Refrigerant Leak
Refrigerant is the chemical compound that absorbs heat from your indoor air and releases it outside. Your AC system is a sealed loop — it doesn't consume refrigerant, so if levels are low, there's a leak somewhere.
Low refrigerant causes the evaporator coil to get too cold (leading to the freezing issue from Cause 2), drops suction pressure below normal operating range, and triggers the system's low-pressure safety switch. The compressor shuts down. Pressure slowly equalizes as the remaining refrigerant redistributes, the safety switch resets, and the compressor starts again — only to hit the low-pressure cutoff within minutes.
Refrigerant leaks are especially problematic in our climate because the system runs so many hours per year. A small leak that might take months to affect performance in a cooler region can cause noticeable problems within weeks during a Gulf Coast summer.
What to do: Refrigerant issues always require professional service. A technician will check pressures, test for leaks (often using electronic leak detectors or UV dye), and repair any leaks before recharging the system. Simply adding refrigerant without finding the leak is a temporary fix that wastes money and harms the environment.
Why Texas Heat Makes Short Cycling Worse
All five of these causes are more severe during extreme heat. When outdoor temperatures exceed 95°F — which is most of the summer in League City and Friendswood — the temperature differential between indoor and outdoor air is at its maximum. Your system has to work harder, run longer, and maintain higher pressures just to do its normal job.
A system that might manage to struggle through short cycling in May becomes completely overwhelmed in July. The compressor overheats faster. Coils freeze more readily. Oversized systems cycle even more frequently as the house heats back up quickly.
This is why short cycling tends to generate the most service calls between June and September — the problem existed earlier but didn't cause enough discomfort to trigger action.
When to Act
If your AC is short cycling:
- Start with the filter. Check and replace it. This solves about 30% of short cycling cases.
- Check for ice. Look at the suction line at your outdoor unit. If it's frosted, thaw the system before running it again.
- Listen to the cycle length. If the system runs less than 10 minutes before shutting off, something is wrong regardless of the cause.
- Don't ignore it. Short cycling causes compressor damage that compounds over time. A $150 service call today can prevent a $2,500 compressor replacement next month.
Frequently Asked Questions
How long should an AC cycle last?
A properly functioning AC system should run for 15-20 minutes per cycle in moderate heat and may run continuously during extreme heat (100°F+). Cycles shorter than 10 minutes indicate short cycling. If your system runs for less than 5 minutes per cycle, shut it off and call for service to prevent compressor damage.
Can a bad thermostat cause short cycling?
Yes, though it's less common than the five causes above. A thermostat with a faulty temperature sensor, poor placement (near a supply vent, in direct sunlight, or on an exterior wall), or wiring issues can send incorrect signals to the system. If the thermostat reads the temperature as lower than it actually is, it will shut the system off prematurely.
Is short cycling an emergency?
It's not a safety emergency, but it is urgent. Every short cycle puts stress on the compressor — the most expensive component in your system. If your AC is short cycling in extreme heat and the house temperature is rising, it qualifies as an urgent service need. Don't wait for the compressor to fail completely.
Short cycling is your AC system telling you something is wrong. The sooner you identify the cause, the less damage accumulates — and the less you'll spend getting it back to reliable, efficient operation.
