The temperature split in an air conditioning system refers to the difference between the return air temperature (air entering the system) and the supply air temperature (air exiting the system). A proper temperature split, typically between 16°F and 22°F (9°C to 12°C), indicates that your air conditioner is cooling efficiently. If the temperature split is too low, it means the system isn’t cooling as effectively as it should, which could be a sign of an underlying issue.

A temperature split lower than the ideal range suggests that:

1. The system is not removing enough heat from the air.

2. The evaporator coil is not functioning efficiently.

3. There may be issues with airflow or refrigerant levels.

• Poor Cooling Performance: Rooms feel warmer than expected despite the AC running.

• High Energy Bills: The system works harder and consumes more energy without effectively cooling the space.

• Prolonged Cooling Cycles: The AC runs for extended periods without reaching the desired temperature.

• Warm Air from Vents: Air coming out of the vents feels only slightly cooler than the room temperature.

1. Low Refrigerant Levels

• Refrigerant leaks or improper charging can reduce the coil’s ability to absorb heat effectively.

2. Dirty Evaporator Coil

• Dirt and debris on the coil prevent proper heat exchange, reducing cooling efficiency.

3. Restricted Airflow

• Clogged air filters, blocked vents, or undersized ductwork can limit airflow across the coil, resulting in a low temperature split.

4. Oversized Air Conditioner

• A system that’s too large for your home cools the air quickly without enough time to remove humidity or reach a proper temperature split.

5. Faulty Thermostat

• An inaccurate thermostat reading can cause the system to operate inefficiently.

6. Blower Motor Issues

• A malfunctioning blower motor may not move air efficiently over the evaporator coil.

7. Improper Duct Insulation

• Heat gain in poorly insulated ducts can reduce the temperature split.

1. Measure the Temperature Split

• Use a thermometer to measure the air temperature at the return vent and the supply vent. Calculate the difference to confirm if it’s below the ideal range.

2. Inspect the Air Filter

• Replace dirty or clogged filters to improve airflow across the evaporator coil.

3. Clean the Evaporator Coil

• Schedule professional cleaning to remove dirt and debris from the coil, restoring its efficiency.

4. Check Refrigerant Levels

• A licensed HVAC technician can inspect for leaks, recharge the system, and ensure refrigerant levels are optimal.

5. Inspect the Ductwork

• Look for leaks, blockages, or poor insulation in the ducts and address these issues to improve airflow and prevent heat gain.

6. Evaluate the System Size

• If your AC is oversized for your home, consider replacing it with a properly sized unit to avoid short cooling cycles.

7. Repair or Replace Blower Components

• Have a professional inspect the blower motor and fan to ensure they’re functioning correctly.

8. Verify Thermostat Accuracy

• Test the thermostat and recalibrate or replace it if necessary to ensure accurate temperature control.

If basic troubleshooting doesn’t resolve the issue, contact a licensed HVAC technician. They can:

• Perform detailed diagnostics.

• Identify and fix refrigerant leaks.

• Assess airflow issues or duct design flaws.

• Recommend system upgrades if necessary.

• Regular Maintenance: Schedule annual HVAC tune-ups to keep components clean and functioning properly.

• Change Filters Frequently: Replace air filters every 1–3 months, or as recommended by the manufacturer.

• Inspect Ductwork: Ensure ducts are clean, sealed, and properly insulated.

• Monitor System Performance: Pay attention to cooling efficiency and address issues promptly.

A low temperature split in your air conditioner’s evaporator coil is a clear indication that the system isn’t cooling effectively. Addressing this issue promptly can improve comfort, reduce energy costs, and prevent further damage to your system. Regular maintenance and professional inspections are key to keeping your air conditioner running efficiently. If the problem persists, consult an HVAC professional to diagnose and resolve the underlying cause.