“The air conditioner is running but the house is not getting cold” is the single most common cooling complaint in Central Florida, and it has a wide range of causes. Some are things a homeowner can check safely in a few minutes. Others are refrigerant, electrical or mechanical faults that need instruments and training.
This page walks through the checks in a sensible order, from the simplest to the most involved, so you can rule out the easy causes before scheduling a repair. Every step below is also written out as text under the diagram, so nothing depends on being able to see the image.
What you are seeing narrows the list quickly:
Confirm the mode is set to COOL rather than FAN, HEAT or AUTO-changeover, and that the setpoint is several degrees below the current room temperature. Check that the fan is set to AUTO rather than ON — with the fan on continuously, air keeps moving through the vents between cooling cycles and feels warm, which many homeowners read as a cooling failure.
Replace weak batteries in a battery-powered thermostat. If the display is blank, the problem may be a blown low-voltage fuse or a tripped float switch cutting the control circuit, which points to the condensate drain.
A restricted filter is the most frequent cause of poor cooling that homeowners can fix themselves. Restricted airflow across the evaporator coil drops the coil temperature, reduces capacity, and eventually causes the coil to ice over — which then blocks airflow entirely.
Hold the filter up to a light. If light does not pass through easily, replace it. In Florida's long cooling season, filters often need changing more frequently than the packaging suggests, especially in homes with pets or ongoing construction dust.
Central systems typically have two circuits: one for the indoor air handler and one for the outdoor condensing unit. If the indoor blower runs but the outdoor unit is dead, the outdoor breaker is a prime suspect. A breaker in the tripped position often sits between ON and OFF; push it fully OFF, then back ON, once.
If it trips again, stop. That is an electrical fault, not a nuisance trip, and it needs to be diagnosed before power is restored.
Walk outside while the system is calling for cooling. The fan on top should be spinning and you should hear the compressor. Clear grass clippings, leaves, mulch and vines away from the coil, and make sure nothing is stacked against the cabinet. The outdoor unit rejects heat, and it cannot do that when the coil is blanketed.
A humming outdoor unit with a fan that will not start is a classic failed-capacitor symptom. So is a fan that starts only after you nudge it — do not do that; treat it as a diagnostic clue and call for service instead.
Check the copper refrigerant lines where they enter the house and, if you can see it safely, the indoor coil. Frost or a solid block of ice means the system must be shut off and allowed to thaw before anything else can be evaluated. Ice is a symptom, not a cause: it comes from restricted airflow, a low refrigerant charge, a dirty coil, or a blower problem.
If the basics check out, the remaining causes generally require instruments. A low refrigerant charge always means a leak, because a sealed system does not consume refrigerant. Simply adding refrigerant without finding the leak is a temporary measure that repeats every season.
Other mechanical possibilities include a compressor that runs but no longer pumps effectively, a failing reversing valve on heat pump systems, a restricted metering device, or a condenser fan motor that is turning too slowly to reject heat.
Do not open high-voltage electrical compartments, do not attempt to discharge or replace a capacitor, do not add refrigerant yourself, and do not bypass float switches, pressure switches or other safety controls. Those devices shut the system down for a reason, and defeating them converts a moderate repair into an expensive one.
For broader planning numbers, see the AC repair cost guide for Lakeland or try the repair cost calculator. Both give educational planning ranges rather than quotes.
The most common causes are a restricted filter, a frozen evaporator coil, a failed capacitor stopping the outdoor unit, a clogged condensate drain that has tripped a safety switch, a dirty condenser coil, or a low refrigerant charge caused by a leak.
Yes. The indoor blower alone only moves air. If the outdoor unit is not running, no heat is being removed from the home and the air from the vents will be room temperature or warmer.
After a thermostat change or a repair, a well-matched system typically lowers indoor temperature gradually, not instantly. If a system runs for hours without dropping temperature at all, something is wrong.
Long run times are common during peak afternoon heat and are actually efficient. Running continuously while the indoor temperature still climbs is not normal and should be diagnosed.
One of the most frequent air conditioning failures in Florida heat, and one of the most recognizable by symptom.
Read moreA sealed system does not consume refrigerant. If the charge is low, something is letting it out and the leak needs to be found.
Read moreIce is always a symptom of something else — airflow, charge or a control problem. Thawing alone never fixes it.
Read moreThe control point for the whole system. A surprising share of cooling complaints start and end here.
Read moreHumid climates produce a lot of condensate. When the drain clogs, the system either shuts down or puts water where it should not be.
Read moreThe heart of the refrigeration circuit. Compressor problems deserve careful diagnosis before any major expense is authorized.
Read moreDescribe what your air conditioner is doing and we can talk through the likely causes and current availability.
211 E Main St, STE #453, Lakeland, FL 33801