AC Not Blowing Cold Air: 5 Reasons and Troubleshooting Tips

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Air conditioners are installed to provide cool air to the room during the heat of the day. These units keep the room at a comfortable temperature setting, which is why an AC unit not blowing cold air is a dilemma for many homeowners.

While it may be concerning when the air conditioner is blowing warm indoor air instead of cold air, there are multiple reasons that may cause this that are relatively easy fixes. You may not even need to go to an HVAC technician at all! However, we recommend setting an appointment with one of our experienced professionals for problems with the internal parts.

Reason Description Solution
Thermostat Settings Temperature is set too high, or the thermostat cannot communicate with the AC system properly due to low batteries. Adjust the temperature to a comfortable level, or change the batteries of the control panel/remote.
Dirty Air Filter Clogged air filters and vents can create poor air circulation, resulting in warm air being delivered by the AC system instead of cold air. Clean the air filter by running it under soap and water, then use a brush to gently scrub away deep-seated grime.
Refrigerant Leak Refrigerant levels are low due to a leak in the refrigerant lines. Have the refrigerant levels topped up, and talk to an HVAC professional to fix the leak.
Issues with Condenser Unit Condenser unit is clogged or dirty, which cannot properly remove humidity from the unit, causing the AC to malfunction. Brush the outdoor condenser coils with soap and water, then rinse to clean.
Issues with Evaporator Coil Evaporator coil might be filthy, clogged, or broken. Contact an HVAC technician to check the evaporator coil, and clean, fix, or replace it.

5 Reasons for AC Not Blowing Cold Air

Reason #1 Thermostat Settings

The most basic issue is with the thermostat. Check whether the thermostat is set at a comfortable temperature, and adjust your setting as you see fit. If adjusting the temperature doesn't solve the problem, there may be an issue with your control panel or the connection between your thermostat and the air conditioner.

Reason #2 Dirty Air Filter

Clogged and dust-filled air filters don't allow for good air circulation in and around your air conditioner. Similar to clogged vents, dust can accumulate on the filter, and can lead to a debris buildup that locks the air out of your air conditioning system. The AC unit may freeze, malfunction, or completely stop working to provide cool air.

Reason #3 Refrigerant Leak

An air conditioner would need refrigerant to keep it running smoothly. The cold air blowing from your air conditioner is made possible by refrigerant lines, as they work to cool the room temperature air. Having a leak in the refrigerant lines means that the air conditioner can no longer properly cool the air, which results in warm air coming from the unit instead.

Reason #4 Issues with Condenser Unit

Your air conditioner would most likely have an outdoor condenser unit. You can easily spot it as a large coil that extends from the exterior into the unit, and it should have fin-like appendages that make it easy to spot. You can get a clogged condenser coil that causes your AC unit to malfunction, resulting in warm air.

Reason #5 Issues with Evaporator Coil

Like the condenser unit and the air filter, the evaporator coil may malfunction or build up with debris. When dirt forms around the evaporator coil, the cold air may cause condensate to freeze, resulting in a frozen evaporator coil. This, in turn, results in an air conditioner blowing warm air instead of cold.

Your evaporator coil might also be due for a replacement if broken, which can be done by a professional aircon repair company. A broken evaporator coil would result in heat going back into your home instead of being exhausted outside. 

5 Tips to Prevent AC Malfunction

Tip #1 Change Thermostat Batteries

Change the batteries in your thermostat, particularly if you have a central air conditioning unit that uses a main control panel. A malfunctioning AC unit is certainly a cause for alarm, but oftentimes, the issue lies with the control panel, particularly with spent batteries.

Tip #2 Clean the Air Filter and Coils

You may already know that you can clean dirty air filters at home with just some soap and water, but you can also do the same for condenser coils in the outdoor unit. Use a brush to scrub the dirt and dust buildup away, then rinse with water. Be sure your air conditioner is unplugged before you do this. Clean these parts once every two weeks for the best care.

Tip #3 Go for AC General Cleaning and Maintenance

Regardless of whether you have a mini-split, window, or central air conditioner, your unit would greatly benefit from a scheduled general cleaning and maintenance check once every six months. Only an experienced HVAC professional should be handling issues with the internal parts of the air conditioner, so schedule a Singapore aircon servicing with us!

Tip #4 Talk to Professional Technicians for Diagnostics and Repair

Check with an HVAC technician if the problem lies with the evaporator coil, fan motor, or any other internal mechanism of your air conditioner. They would be able to diagnose and repair your unit, especially if you're unsure where the issue lies. Never attempt to fix the problem yourself as it may lead to further damage to the unit, or bodily harm.

Tip #5 Clear Vents from Blockage

Check the vents for any blockage. Use a vacuum cleaner with a brush attachment, or a long stick to clean a clogged filter or vent blockage. Oftentimes, you may find dried leaves, dust, and large pieces of debris in the outdoor unit, so be sure to check the vents outdoors as well. Clear vents will keep your air conditioner running smoothly.

Cool It!

Don't be immediately alarmed when your AC system stops blowing cold air into the room. Unplug the unit, and check for any possible causes and easy fixes first, before deciding to call a technician. However, if the issue cannot be remedied at home, we at Luce Aircon are more than glad to give your unit a thorough checkup!

Check out our article on aircon fan keeps running when off
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