Why is My A/C Blowing Warm Air from the Vents?

September 29, 2021by Larry Wilson

Do you make a habit of feeling the air coming from your HVAC system vents? All homeowners should pay close attention to any temperature changes and monitor it closely. The indoor blower section of your HVAC system works year-round, even in the summer months. This is how air is circulated throughout your home.

Being diligent and monitoring the air flowing through the vents could help you prevent a small issue from becoming an emergency.

Mechanics of your HVAC system

Air-conditioning equipment consists of a fan to draw air into the system. The air from the fan moves across a cold evaporator coil.  The cold air is then dispersed throughout your home through the ductwork and vents. Heat from inside the home is then released through the outdoor condenser coil. Refrigerant returns to the indoor unit and the cycle continues.

Reasons warm air could be coming through the vents 

If you notice your air-conditioner cycles on, but is blowing warm air throughout the home, one of these issues could be the problem:

Refrigerant Levels

Low refrigerant levels, or if the unit is overcharged can cause the system to disperse warm air. Refrigerant can potentially leak out of worn service valves, pin hole leaks in the indoor or outdoor coils, loose joints, or deteriorated parts.

The Importance of Your Air Filters 

Restricted air filters can lead to a clogged evaporator coil. When an evaporator coil gets clogged, not enough free airflow is generated for the air-conditioner to function properly.

This can result in a frozen indoor coil. A frozen indoor evaporator coil impedes the flow of cool air to your home, and it can cause permanent damage to your home’s heating and air system.

Air filters need to be replaced every 30-60 days, depending upon the activity in your home, pets, the age of your home, and filter type.

Check Your Thermostat

It may sound obvious, but if you feel warm air from the vents, the first thing you should check is your thermostat. It may have accidentally been set to “heat” mode, or “fan only” mode.

Simply, change the thermostat back to “cool” and verify your air-conditioner begins to circulate cool air again.

Air leaks in your ductwork in Burlington

In older homes, ductwork can develop leaks and the conditioned air will escape. This can lead to unnecessary cooling of your crawlspace or attic, which will cause un-needed strain on the cooling system. Since much of the ductwork is probably hidden or difficult to access, contact your local Burlington professionals at LM Wilson Heating & Air to determine where the leaks are and get it repaired or sealed.

Dirty condenser coil

A dirty condenser coil can cause your home’s air conditioning system to underperform. Visually inspect your outdoor unit and make sure nothing is caught in it, which might interfere with any mechanical parts.

Check to see if the outdoor looks dirty, does it appear to be clean or dirty? Keep leaves, tall grass, and debris away from the outdoor unit.

Never attempt to reach inside the unit, especially when it is running. If the debris is not easy to remove, contact an HVAC contractor to perform a maintenance to clear the debris and verify your system is working at optimum performance.

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