Why is My A/C not Blowing Cold Air?

Don Ludington • Aug 07, 2023

When summer temperatures rise into the triple digits, your air conditioner provides indoor comfort and can be a lifesaver. Even a well-insulated house can get uncomfortably hot on a 100-degree day. However, if you have a health condition that gets exacerbated by heat or simply a low tolerance to heat, adequate climate control adds another layer of safety to your home. So, what happens when your air conditioner stops blowing cold air? In this blog, we will explore the common reasons behind your air conditioner not cooling enough, and provide you with the best possible solution, especially if you find yourself unable to resolve the issue on your own.

Common Reasons Why Your Air Conditioner is not Cooling

Incorrect Thermostat Settings 

When your AC is not blowing cold air, the cause can sometimes be related to your thermostat settings, such as forgetting to set it to “Auto” or “Cool.” As the weather starts warming up after a long cold spell, it's easy to overlook changing the setting from “Heat.” Don't worry; this happens to many people, so you're not alone. The good news is that this issue can often be quickly fixed.

If you've already ensured that the thermostat is set correctly and the problem persists, the next step is to check and replace the batteries if they serve as the power source. However, if warm air continues to come out of the vents, it might be time to call an AC specialist for a thorough system check.

Dirty Air Filter

Another possible cause relates to the current condition of your air filter which requires regular cleaning. If you pull your filter out and see dust accumulated on the surface, then you can gently brush or wipe it off. Furthermore, if you have been using the same filter for a couple of months, then it’s time to change it. Ideally, you shouldn’t go beyond three months, but some types and brands may need to be changed monthly. Plus, having an indoor pet means that you have to change the air filter quite often due to pet hair and dander.

Blocked Condenser Unit 

You might also check your condenser unit for dust or debris. Because it’s located outdoors, this mechanism is especially vulnerable to blockage. So, a clogged condenser affects the performance of the entire HVAC system by severely reducing the amount of cold air that circulates due to the blockage preventing air from circulating toward the coils and refrigerants. When this occurs, you’ll feel hot air coming from the vents.

Damaged Heat Pump

Along with blocked condensers, a damaged heat pump is one of the most common reasons behind the AC not blowing cold air. Just like the condensers, this unit has to be checked regularly for blockage to keep it running in prime condition. If it’s not running at all, your indoor unit might continue working, but the air won’t feel cold which makes it difficult to quickly discern the cause of this issue. Nonetheless, one of the first steps you can take in figuring out what’s happening to your heat pump is to push the reset button. If that doesn’t work, then you may have an electrical issue that needs to be fixed by a professional.

Frozen Evaporator Coil

You might also check the evaporator coil to see if it’s frozen. Inadequate air flow often causes this problem along with dirt accumulation, a clogged air filter, or backed-up drains. Another common cause involves leaks in the coil and a low level of refrigerant.

Refrigerant Leak

And if you’re running low on the cooling source itself, the refrigerant, then your air conditioner will not blow cold air. Moreover, your home will feel more humid, and therefore, hotter if there’s a refrigerant leak which can be hard to identify if the leak is still small. Hence, it needs to be addressed right away to avoid further damage to your HVAC system.

Undersized Air Conditioner

Lastly, you may have to reconsider the size of your air conditioner. Sometimes in the name of saving money, some folks may try a small unit. However, this option is not wise because the unit won’t provide adequate cooling, and you end up running the motor to the point of shortening its lifespan. So the best choice is to choose an air conditioner that meets the specifications for your home’s square footage. As a bit of advice on figuring out the correct size of air conditioner, try measuring all the rooms and multiply the sum of those measurements by 25. This formula should give you the approximate size of the unit that you’ll need.

Get Assistance for Air Conditioners that aren't Cooling Properly

When you have the problem of the AC not cooling, you can attempt to resolve the causes on your own. However, as you can tell, some of these AC mishaps must be diagnosed and repaired by a professional for the sake of safety. Luckily, you need to look no further than our experts at Rizzo HVAC. We’ve been specializing in air conditioning and heating since 1968, and your comfort and climate control remains our top priority. Call us today, and we’ll get to the bottom of your AC’s problem and provide an effective solution.


"Discover the common reasons why your A/C is not blowing cold air and find quick fixes, including thermostat settings and battery checks. Learn when to call an AC specialist for a thorough system check to resolve the issue and stay cool this season.

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