What Should You Do If Your AC Is Blowing Out Warm Air?

woman operating thermostat

It’s not uncommon for air conditioners to start blowing out warm air which can be caused by several problems.

Summer has us in its grips right now. Temperatures are reaching seasonal highs and may climb even further during the weeks to come. On top of that, high humidity levels are making for stifling outdoor conditions and potentially dangerous heat indexes. 

All that leaves many of us wishing for cooler weather. It also makes us grateful for air conditioning. Without it, we’d be even more uncomfortable indoors than we are outside. Unfortunately, though, air conditioning systems don’t always live up to our expectations. That’s particularly true when they’re blowing out warm air instead of cool.

Why Is My Air Conditioner Blowing Out Warm Air?

Every year, quite a few people are dismayed to find that their air conditioners aren’t doing their jobs. If you’re in such a situation right now, you’re most likely frustrated and, of course, miserably hot. No doubt, you want to resolve the issue as quickly as possible

It’s not uncommon for air conditioners to start blowing out warm air especially if they’re running constantly, trying to beat the summer heat. This can be caused by several problems. Some of them may require you to contact an HVAC technician for help. Others are simple matters you can take care of on your own. Take a look at some of the reasons your AC may be working against you rather than for you.

Clogged Air Filters

Clogged air filters are often the culprit when air conditioners are blowing out warm air. Filters are designed to remove debris, allergens, and pathogens from the air. That prevents those unwanted particles from circulating through your AC system and back into your home or business. Over time, though, the particles in the air build up in the filter and keep air from flowing through it the way it should. 

Air conditioners are equipped with evaporator coils. Those components remove heat and humidity from the air. If the AC system isn’t drawing in air the way it needs to because of a clogged filter, there may not be much air circulating over the evaporator coil. In turn, the unit can’t send cooled air out of the AC vents. Instead, you get warm air.

Check your air filter, and if it’s covered in dust and pet hair, replace it. That may be all it takes to get the cold air flowing again. If the filter doesn’t appear to be dirty, though, other forces may be at work.

Thermostat Trouble

Thermostat problems can also prevent air conditioners from working properly. Someone may have simply turned up the temperature, causing the HVAC system to blow out warm air. With older, non-programmable models, people have been known to inadvertently switch the thermostat to “heat” or “fan” instead of “cool”. 

Check your thermostat to be sure it’s set correctly. If it’s not, changing the setting to the “cool” mode or a lower temperature could help. On the other hand, your thermostat may not be calibrated properly. They tend to lose calibration over time especially if it has been a while since routine maintenance was performed on the HVAC system. If that’s the problem, you’ll need to have it professionally recalibrated. 

Low Outdoor Airflow

As we touched upon earlier, air conditioners work by drawing heat and humidity out of indoor air. Still, those undesirable elements have to go somewhere. That’s where the AC’s outdoor unit, also known as the condenser, comes into play. It sends the hot air outside where it belongs. If something is blocking the condenser, preventing it from doing its job, the hot air may not be escaping the way it should.

Check the outdoor unit to make sure nothing is blocking it. Shrubs and other foliage should be cut back at least a foot from the unit to give it room to breathe. Nothing should be placed on top of the unit, either. At the same time, be sure the condenser isn’t clogged with leaves, dirt, and other debris. Anything that blocks the outdoor unit’s airflow could cause the system to blow hot air into your home or business. 

Frozen Evaporator Coils

Frozen evaporator coils can also cause air conditioners to put out warm air. Remember, the evaporator coils are filled with refrigerant, and they draw heat and humidity from the air to cool it. If the coil is covered in a layer of ice, the air can’t get to it. As such, it won’t be cooled properly.

If the evaporator coil is frozen, you may also notice ice forming on the outdoor unit or the line running from the unit into your home or business. Frozen evaporator coils need to be thawed. You can do that by turning off the air conditioner and letting it sit idle for a while. Alternatively, you can switch the thermostat to the fan-only setting. That’ll keep warm air circulating through the system and may help the coil thaw faster. Once it’s thawed, the AC system should start blowing out cool air again. 

Determining if a frozen coil is the problem isn’t always a straightforward process. You may not see any of the previously mentioned outward warning signs. Like many people, you may not feel comfortable trying to access the evaporator coil to find out if it’s frozen. If that’s the case, you can certainly contact us for assistance. 

Additionally, it’s important to understand that evaporator coils shouldn’t freeze to begin with. That’s often a sign of deeper problems. If your evaporator coil freezes, even if you’re able to thaw it, consider having us inspect the system to find out what caused the malfunction.

Low Refrigerant Levels

Low refrigerant levels can also cause air conditioners to blow out warm air. If there’s not enough refrigerant pumping through the evaporator coil, it can’t remove heat and humidity the way it’s supposed to. If low refrigerant is causing your air conditioner to misbehave, you’ll need to contact us for professional intervention.

Damaged Ductwork

Damaged ductwork could also send warm air flowing from an air conditioner’s vents. Ductwork carries cooled air from the AC into your home or business. It’s supposed to be a closed system, but it can sustain damage over time. If there are tears in the ductwork, warm air could be coming in and interfering with the cold air your AC system is trying to provide. You’ll need to have those leaks repaired.

Staying Cool in Spite of the Heat

Air conditioning systems can make summertime much more tolerable. When they’re blowing out warm air instead of fresh, cool air, though, they don’t help very much. Several problems can detract from the effectiveness of your AC system. Check the obvious, simple-to-fix possibilities first, like your air filters, thermostat settings, and blockages around the outdoor unit. If neither of those seems to be the problem, you can work your way up to the more serious issues. 

Valley Heating & Cooling is always on hand to help keep your home or business cool and comfortable. Don’t hesitate to contact us if your air conditioning system isn’t doing its job. Our technicians can find the problem and resolve it. 

We also offer HVAC maintenance services. When you have us check the air conditioning system in the spring before the temperatures start to climb, we can catch potential issues early on. That’ll give us a chance to take care of them so they won’t leave you sweating later on in the summer.