Why Your AC Has Weak Airflow When You Turn It On for the First Time in Spring

Airflow restrictions often develop gradually, and you might not notice the issue until you switch to cooling for the first time in spring. Cooling systems typically run longer cycles than heating systems, which can expose problems that were less obvious during the winter months.

There are also functional ways in which cooling and heating differ. It may feel like airflow has changed even when your AC or heat pump is working correctly.  

Why There May Not Be a Problem

The temperature of the supply air may affect how airflow feels to occupants.

The air being pushed out by a gas furnace in heating mode may be 100–130°F. If the indoor air is only 68°F, that difference is large and noticeable. In cooling mode, the air coming out of vents may be 55–60°F, which is a more subtle temperature difference in a 78°F home.

Some homeowners mistake that ‘softer’ feeling air for a change in airflow when it’s really just a consequence of a less extreme temperature difference of the supply air in cooling mode.

Why Malfunctions May Be More Noticeable in Early Spring

Air conditioners often run longer cycles than furnaces. Longer cycles can make airflow problems that were less noticeable during winter heating easier to detect.

In many homes, spring is the first time the AC system has been used since the previous summer or fall. Issues that developed gradually over months of disuse may only become noticeable once the system begins running again.

In most homes with separate gas furnaces and ACs, the evaporator coil used for cooling sits above the furnace and air must pass through that coil when the AC operates. If airflow through the coil is restricted, the effect often becomes more noticeable once the system switches to cooling.

Common Causes of Weak Airflow When the AC Starts Running

Dust or Debris on the Evaporator Coil

The evaporator coil contains tightly spaced aluminum fins that air must pass through before circulating through the home. Over time, dust and debris can accumulate on these fins. Even a thin layer of buildup can reduce the amount of air that moves through the coil.

Blower or Fan Performance Issues

The blower motor and fan wheel push air through the HVAC system. If the blower is not operating at the correct speed or the fan wheel has accumulated dirt, the system may not move as much air as expected.

Some systems also use different blower speeds for heating and cooling. If those settings are incorrect, airflow during cooling may feel weaker than normal.

Duct Restrictions or Leaks

Leaks in ductwork can also allow conditioned air to escape before reaching the rooms it is intended to cool, creating uneven airflow throughout the home. The consequences may feel more noticeable in cooling mode, but it’s not a cooling-specific issue.

Closed Dampers or Blocked Vents

Airflow problems are not always caused by equipment issues. Closed dampers in the duct system, seasonal adjustments to vents or furniture blocking registers can all reduce airflow to certain areas.

When the AC begins running again in spring, these restrictions may make vents seem weaker than expected.

Why Spring Maintenance Helps Catch Airflow Problems Early

Spring is an ideal time to have an HVAC system inspected because it allows technicians to identify the source of airflow problems before the hottest weather arrives.

If your air conditioner seems to have weak airflow when you turn it on for the first time this spring, a professional inspection performed by Tom’s Mechanical HVAC technicians can help identify the cause and ensure the system is ready for the months ahead.



Call us at (817) 277-4493 to schedule AC maintenance.