High Energy Bills & Long Runtime
An AC that runs continuously without cycling off is either correctly sized and working hard against a genuinely heavy load, or it's losing capacity or delivered air faster than it can replace it. Variable-speed and properly sized systems are designed to run long, steady cycles on purpose. If runtime is constant and the house still isn't comfortable, look at airflow, coil condition, refrigerant charge, and duct leakage as candidate causes.
Many modern systems, especially variable-speed and two-stage units, are engineered to run long, low-capacity cycles rather than short bursts, because that improves humidity control and comfort. If the house holds its temperature, this is normal operation, not a problem.
Extreme outdoor temperature and humidity, direct sun on the house, or a house full of people and appliances can push even a correctly sized system into continuous operation on the worst days of the year.
A thermostat set aggressively low, or placed somewhere that reads warmer than the rest of the house (near a window, in direct sun, near a heat-generating appliance), can call for cooling that never truly satisfies.
A dirty filter, dirty coil, or underperforming blower reduces the air moved per cycle, which reduces delivered capacity and keeps the call for cooling active longer.
Reduced charge lowers cooling capacity per hour of operation, which can turn what should be a normal cycle into continuous running. This requires a licensed HVAC contractor to diagnose safely.
If air is escaping the ducts before reaching the rooms, or a restricted return limits how much air the system can pull and condition, the thermostat call for cooling can stay active well beyond what should be a normal cycle.
Stick to what you can see, feel and hear. Leave electrical panels, refrigerant, combustion appliances and equipment internals to a licensed professional.
The thermostat calls for cooling until the air around it reaches setpoint. If duct leakage or restriction reduces how much conditioned air actually reaches the living space per hour of runtime, that call for cooling simply stays active longer — the equipment keeps running because, from the thermostat's perspective, the job isn't done.
This looks identical to an equipment capacity problem from inside the house, which is why runtime alone doesn't tell you where the loss is happening. A duct leakage test isolates the delivery side of the equation so it can be ruled in or out with a number.
Duct Daddy specialises in duct leakage testing and duct sealing. We do not perform mechanical HVAC repair, refrigerant work or equipment replacement. Contact a qualified HVAC contractor if any of the following apply:
On the hottest, most humid days of a Louisiana summer, continuous or near-continuous runtime is common even for well-sized, well-maintained systems, particularly variable-speed equipment doing extra work to control humidity.
The distinction that actually matters locally is whether the house is comfortable during that continuous runtime, or steadily losing ground to the heat despite it.
See the communities we serve.
If the house never quite catches up despite constant runtime, a duct leakage test tells you whether lost delivery is part of the reason.
Continuous runtime without a satisfied thermostat means capacity or delivery is falling short of the heat load.
Long runtime after a replacement can be normal variable-speed behaviour, or a sign the equipment is fighting a load or duct problem.
Why leakage more often reduces delivered air than register velocity, and when it does neither.
Weak airflow across the whole house, doors that resist closing, and a struggling system can all point to a starved return side.
How to read a CFM25 result — relative to what, judged against what, and what it can't tell you alone.
Browse every symptom in the troubleshooting center.
Schedule a duct leakage evaluation and get measured numbers for your home — not a guess.
