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7 Reasons Why Your Is AC Not Blowing Cold Air

Nothing spells bad news for homeowners than an AC unit refusing to blow cold air. If left unchecked, this problem can cause hot days and sleepless nights in your home. Here’s the good news: you can solve this problem without needing to pay an HVAC technician. There are various possible reasons that might be causing this issue. Some are easier to solve and its possible to do DIY repairs. In other scenarios, you might need a contractor to fix it. In this article, well cover what causes an AC not to blow cold air and how you can fix it to get your air conditioner blowing cold air once again. 

Seven Reasons Why Your AC Is Not Blowing Cold Air 

AC not blowing cold air

Compressor is Faulty

A faulty compressor is a common reason why some air conditioners refuse to produce cooled air. If your compressor fails to distribute refrigerant, the cooling capacity of your AC will suffer and lead to more days spent in the heat.

There are many things that can cause your compressor to malfunction. For example, debris buildup in the compressor’s internal area may lead to poor performance, so in heat pumps they have the opposite effect. 

If a routine inspection of the compressor fails to turn up any clues, then you should call an HVAC technician. Depending on the severity of the problem, the tech may be able to fix the compressor.

You don't need to freak out if your compressor develops a fault. Not every compressor-related issue becomes severe enough to warrant a replacement, especially if you hire a quality HVAC contractor.

Nonetheless, you should be prepared to spend considerable sums to fix the problem, especially if buying a new compressor is necessary. The average compressor costs around $1500-$2000 —  more reason why preventive AC care is essential.

Low Refrigerant Levels

Refrigerant, aka freon, circulates through the AC unit and controls the cooling process. In most cases, you don't have to replace refrigerant, as the liquid can last a long time without losing efficacy. 

But there are cases when a refrigerant leak occurs in your whole-house AC unit, which may cause refrigerant levels to drop. You can read refrigerant levels using an HVAC gauge. Apart from causing the AC to stop blowing cold air, it can even completely freeze it. Apart from that, you may notice the following:

  • Frosting on AC components
  • Hissing noises
  • Delayed cooling

As a rule of thumb, you should never try to fix a refrigerant leak yourself. Finding and repairing such leaks takes skill, and you need to be certified. So unless you have certifications and the right tools like a refrigerant leak detector, you should call your HVAC expert for help. 

Drain Pipe is Clogged 

While cooling your house is your air conditioner's main job, it helps reduce humidity as well. The evaporator coil absorbs moisture from the air and transfers it outside before returning cool, dry air indoors.

Here's the thing: the moisture can quickly build up and cause significant problems over time. Which is why AC units include a drain for disposing of the water. 

Should your drain not remove water, the compressor is likely to suffer flooding and shut down prematurely. What then happens is that your AC cannot produce cool air, even though other components are working. So instead your stuck with warm indoor air instead of cooled air.

Fixing a blocked AC drainage is easy once you know what to do. The first task on your checklist should be to inspect the drain for signs of debris. If you find materials like leaves, sticks, and algae in the drainpipe, clean the outdoor unit with soap or other cleaning chemicals.

Thermostat is Malfunctioning

The thermostat is a critical component that controls the operation and functioning of your air conditioner. As with other crucial central AC equipment, thermostat problems can affect its performance and cooling capacity. 

A common problem with thermostats comes from the batteries. The batteries in your thermostat are prone to wearing out near the end of their service life, which may affect the latter's operation.

It’s also possible that the wiring in the thermostat is suspect. This is common among owners with newly installed central air conditioner units. It's all too easy for owners to skip proper wire installation, but this will only cause problems down the road.

A more advanced solution would be to check the health of the batteries. When was the last time you changed the batteries? Old batteries may be unable to power the thermostat, so you may need to replace them. For wiring issues, you may want to have an expert look at the air conditioner before trying anything.

Air Filter is Dirty 

A dirty air filter is terrible for your air conditioner unit because it reduces airflow and puts pressure on other components to compensate for air loss. Worse, the central air conditioning system may stop working and leave you without any means of cooling.

If you trace the problem to a dirty air filter or clogged filter, cleaning the device is the logical next step. Remove the dirty or clogged filter which will more than likely be located around the indoor air handler unit and clear out debris buildups or just simply switch it out for a new one. AC filters are pretty affordable, and you can get a set for around $60. 

A dirty air filter can also cause other issues that may lead to tripping the circuit breaker.

Ductwork is Leaking

Ductwork is a series of metal tubes that circulate cooled air from your HVAC unit throughout your home. Leaky ducts absorb hot, uncooled air, which increases the AC unit's temperature.

Because ducts are hidden from view, detecting a leak may be difficult. However, here is a list of warning signs to help you detect leaks in the ductwork:

  • Higher-than-average energy consumption
  • Excessive dust particles
  • Problems cooling specific areas

AC Has Power Problems 

Your HVAC system needs electricity if it's to function correctly and cool the home. If the AC isn't getting the requisite power, producing uncooled air is inevitable.

Asides from forgetting to plug in the air conditioner, different power issues could affect it. It’s common for owners not to plug in the unit correctly or fail to use the correct voltage. Additionally, it’s common for electrical components to suffer damage due to electrical surges. Signs of damaged electrical equipment in your central air conditioning system include blown fuses and tripped breakers.

Start diagnosing the problem by checking to see if you plugged it incorrectly. Next, check the amp breaker and fuse for signs of damage. If that fails to reveal anything, get an HVAC technician to help.

Dealing with an AC that refuses to cool can be difficult, especially in humid and uncomfortable weather. Fortunately, you can fix these issues by following the steps listed in the article. However, you should know that not every problem can be solved with DIY fixes. HVAC technicians use professional tools like AC vacuum pumps and digital gauges to help them figure out critical problems. If your AC fails to cool after applying these fixes, consult a professional for help.

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Justin Edwards

Justin Edwards is an HVAC contractor in Ann Arbor, Michigan. Before working in HVAC, he worked in all sorts of other contracted-related jobs. When he's not doing HVAC-related work, he's writing DIY articles and sharing his expert insights.