There is a particular kind of anxiety that comes from standing in your Orlando home with the AC running — and running, and running — long after the thermostat should have told it to stop. In Central Florida's heat, an air conditioner that won't shut off is not just an annoyance; it is a sign that something is wrong, and it is likely costing you money with every additional hour it runs. At AmeriTech Air Conditioning and Heating, this is one of the most common service calls we receive throughout Greater Orlando, and the causes range from simple fixes you can handle yourself to system issues that require professional attention.
Understanding Normal vs. Abnormal AC Runtime
Before diagnosing an AC that "won't shut off," it's important to understand what normal runtime looks like in Florida's climate. During the hottest days of an Orlando summer — when temperatures are in the mid-90s — it is entirely normal for a properly sized, properly functioning air conditioner to run for 20 to 30 minutes out of every hour, or even longer during peak afternoon heat. A well-functioning system should eventually reach the thermostat's set temperature and cycle off, then stay off for 5 to 10 minutes before the next cycle begins.
If your AC never reaches the set temperature and never shuts off, or if it shuts off very briefly only to start again immediately, you have a genuine problem that needs to be addressed. Here are the most common causes.
1. Clogged Air Filter
A severely clogged air filter restricts the airflow through the evaporator coil. When airflow is reduced, the system cannot effectively absorb heat from your indoor air — meaning it runs longer without successfully lowering the temperature. In some cases, the restricted airflow causes the evaporator coil to freeze, which further blocks airflow and causes the system to run continuously while cooling almost nothing. Checking and replacing your filter is always the first step whenever your AC is underperforming.
In Orlando's environment — with high pollen counts, dust, and pet dander — air filters need changing every 30 to 60 days in most homes. A filter that looks gray or brown and has visible debris packed into it is definitely overdue for replacement. After replacing a clogged filter, allow the system to run for an hour and check if performance improves.
2. Blocked or Leaking Ductwork
If significant portions of your conditioned air are escaping through duct leaks before reaching your living space, your system must run longer to compensate. Studies of Central Florida homes consistently show that the average home loses 20 to 30 percent of conditioned air through duct leaks in the attic — a staggering waste that forces the AC to run far longer than it would with a sealed system.
Similarly, partially collapsed flex duct — very common in older Orlando homes where the attic's heat and humidity cause duct material to deteriorate — creates significant airflow restrictions that reduce cooling delivery to certain rooms. If you notice that one or two rooms stay warm while others are comfortable, and your system runs continuously without cycling off, duct problems are a strong suspect that AmeriTech can diagnose and correct.
3. Refrigerant Leak
Refrigerant is the working fluid that makes cooling possible. When your system has a refrigerant leak and the charge (the amount of refrigerant in the system) drops below the proper level, the system's ability to absorb heat from indoor air drops proportionally. A severely undercharged system can run continuously without cooling the home adequately — essentially operating but not performing its fundamental function.
Signs of a refrigerant leak include warm air from the supply vents despite the system running, ice forming on the refrigerant lines near the indoor air handler, hissing or bubbling sounds from the refrigerant lines, and — over time — continuously rising electric bills. A refrigerant leak is not something that resolves itself or can be addressed with DIY additives. AmeriTech's EPA-certified technicians can locate the leak, repair it, and recharge the system to the correct level.
4. Frozen Evaporator Coil
A frozen evaporator coil is a condition where ice forms on the coil surface, progressively blocking airflow and severely reducing cooling capacity. The system continues running but can deliver almost no cooling because the ice-encrusted coil cannot effectively exchange heat with the air flowing over it. A frozen coil typically appears as frost or ice on the copper refrigerant lines near the air handler, and may cause water dripping or overflowing from the air handler when the ice melts.
The two most common causes of a frozen coil are a severely restricted airflow (clogged filter or blocked vents) and low refrigerant charge. If you suspect a frozen coil, turn the system to fan-only mode (without cooling) for 2 to 3 hours to allow the ice to melt, then check and replace the filter before restarting. If the coil freezes again after the filter is replaced, low refrigerant is likely the cause and you need professional service.
5. Faulty Thermostat
The thermostat controls when your AC turns on and off by measuring the room temperature and comparing it to the setpoint. A faulty thermostat can cause the AC to run continuously in several ways:
- Incorrect temperature reading: If the thermostat is reading the room temperature as higher than it actually is, it will keep calling for cooling even after the room has reached the setpoint. This can be caused by a thermostat positioned in direct sunlight, near a heat source, or in a particularly warm location in the home.
- Stuck relay: Some older thermostats have mechanical relays that can stick in the "on" position, keeping the AC running regardless of the temperature reading.
- Misconfiguration: Modern digital and smart thermostats have settings that can accidentally be configured to run the system continuously — check your thermostat settings carefully and consult the manual.
- Low battery: A thermostat with failing batteries can behave erratically, including failing to signal the AC to shut off at the appropriate time.
Try replacing the batteries as a first step. If the problem persists, AmeriTech can test the thermostat and replace it if necessary — we carry a range of thermostat options including smart thermostats that can improve both comfort and efficiency throughout your Maitland or Winter Park home.
6. Wrong System Size (Undersized AC)
An air conditioner that is too small for the home it is trying to cool will run continuously on hot days because it simply cannot keep up with the heat load. This is a sizing problem, not a repair issue — the system is working as designed, but it was never properly designed for this application. In Central Florida's intense heat, a system that is even half a ton undersized for a given home can run continuously from noon to evening on a 95°F August day.
This is why AmeriTech always performs a proper Manual J load calculation before recommending a replacement system. If you have a relatively new system that runs non-stop on hot days without reaching the setpoint, it may have been undersized by the original installer — something AmeriTech can verify and correct if needed.
7. Failing Compressor or Low Efficiency Due to Age
As AC compressors age, they gradually lose capacity — they continue to run but can no longer move refrigerant as efficiently as when they were new. A 12 to 15-year-old system in Florida may have lost 20 to 30 percent of its original cooling capacity due to compressor wear, coil degradation, and other age-related factors. This reduced capacity means the system runs longer and longer to achieve the same cooling result — until eventually it cannot keep up at all on the hottest days.
If your system is over 10 years old and has started running continuously during weather conditions that used to be manageable, age-related efficiency loss is a likely contributor. AmeriTech can evaluate whether targeted repairs can restore adequate capacity or whether replacement is the more economical long-term solution.
Humidity and Your AC's Runtime: The Florida Factor
One aspect of AC operation that is particularly relevant for Greater Orlando homeowners is the relationship between humidity and runtime. Your air conditioner serves two purposes simultaneously: it lowers air temperature, and it removes moisture from the air. In Central Florida's notoriously humid climate — where outdoor relative humidity regularly exceeds 80% during summer months — the dehumidification function of your AC consumes a significant portion of its total cooling capacity.
This means that on days when the outdoor air is both hot and very humid, your AC must run longer than on equally hot but drier days to achieve the same indoor comfort level. If your system runs continuously on extremely humid days but does eventually shut off and maintain the set temperature, this may be within normal operating parameters for Florida's climate. However, if the system never achieves adequate humidity control — leaving your Maitland or Kissimmee home feeling clammy even when the temperature is at the setpoint — your system may be oversized (not running long enough per cycle to remove adequate moisture) or may have a refrigerant issue affecting its dehumidification capacity.
A variable-speed system with enhanced dehumidification mode can significantly improve both humidity control and energy efficiency for Florida homes that struggle with this issue. AmeriTech can evaluate whether your existing system's design is contributing to humidity problems and recommend solutions ranging from a dehumidifier add-on to a system upgrade.
Call AmeriTech When Your AC Won't Shut Off
An AC that runs continuously is not just uncomfortable — it is expensive. Every extra hour of runtime adds to your electric bill, and if the root cause is something like a refrigerant leak or a failing compressor, continued operation under those conditions accelerates the damage. The sooner the problem is diagnosed and corrected, the better the outcome.
AmeriTech Air Conditioning and Heating has been diagnosing and resolving AC performance problems throughout Orlando, Winter Park, Maitland, Kissimmee, Sanford, Oviedo, Apopka, Altamonte Springs, Longwood, and all of Central Florida since 2009. Our factory-trained technicians arrive in fully stocked service vehicles and complete most diagnostic and repair visits in a single appointment. With a 4.9 Google rating and Google Guaranteed status, we are the team Greater Orlando trusts when things go wrong. Call AmeriTech at (407) 532-8000 today.
Practical next steps: My AC Won't Shut Off! What's Wrong
- Orlando-area timing: Schedule service before peak summer demand; Central Florida humidity and runtime stress systems earlier than northern climates.
- Efficiency context: New Florida installations must meet current SEER2 rules; many older systems still use R-410A equipment that can be serviced by EPA-certified technicians.
- Documentation: Keep records of maintenance, repairs, and any warranty registration — AmeriTech can help verify coverage on Carrier-authorized work.
Why homeowners choose AmeriTech
- Founded 2009, serving Orlando, Winter Park, and Maitland first, with 12 vehicles across the Greater Orlando metro.
- factory-trained technicians, EPA Certified, Google Guaranteed, and Carrier Authorized — quality you can verify.
- Questions? Call (407) 532-8000 for honest guidance on repair versus replace in Central Florida.