Why Is My AC Not Blowing Cold Air?

With record heat waves becoming the new normal in many regions, air conditioning has become more important than ever. A properly functioning air conditioner can make a miserably hot day tolerable. So when you have an air conditioner that malfunctions in the summer you don’t want to waste any time fixing the problem. This is particularly true if your air conditioner is no longer blowing cold air.

If your AC unit is not blowing cold air it may be leaking refrigerant. If the evaporator coil is frozen then you likely have a refrigerant problem. Alternatively, there could be a problem with your thermostat. There is also a chance your air filter, drainage pipe or condenser unit is dirty or clogged. Check and clean these areas and then check if your AC blows cold air again.

There are several potential causes for your air conditioner to be working improperly, causing it to blow warm air instead of hot air. Luckily, the six common reasons your air conditioner is not blowing cold air are listed below. All of them are fairly easy to check. Even better, several of them have fixes you can do yourself fairly simply.

One of the most common reasons why an air conditioner is not blowing cold air is because it is leaking or low on refrigerant. When your air conditioner is low on or is leaking refrigerant you will notice an increased humidity in the home and increased temperature. If this does continue, you will see an increase in your electricity usage as well, as your unit will be working much harder to perform (even if it is performing poorly).

When you suspect your conditioner is leaking refrigerant then you should check your evaporator coils. If you notice ice on your cooling coils (or a small puddle underneath where ice melted), then there is a good chance you are leaking refrigerant. Another sign the source of your air conditioning problem is low refrigerant is a bubbling or hissing sound coming from the AC unit itself.

If you have a refrigerant issue, it is best to call an air conditioning or HVAC specialist. This will get the problem officially diagnosed and resolved properly.

It might seem too simple to be the source of your cooling issue, but the thermostat is often the reason your AC is not blowing cold air. If you have an electric thermostat, the first thing you should do is check the batteries. If it has been some time since you replaced your batteries, do so.

Some thermostats make it difficult for you to manually override. Make sure you are in manual mode, and then lower the temperature. Try lowering the temperature on your thermostat lower than normal. This could potentially “wake up” your ac unit from its sleeping or dormant state. Once the AC unit wakes up, it should respond normally once more.

Another possible cause for your AC unit to no longer blow cold air is an old, overfull filter. If you have not been in the habit of regularly cleaning and changing your AC or HVAC filter then this may be the source of your problem. When you have a clogged filter, your air conditioner struggles to get the fresh air it needs in order to function properly. This puts undue strain on the unit. It can cause all sorts of problems, including causing your AC to blow warm instead of cold.

You should be in the habit of replacing and cleaning your AC vents on a regular basis. If your unit is experiencing issues, locate the filter, and swap it out for a new one. When the filter looks clogged and dirty, then you may have found the source of your problem.

If you have an HVAC system, this means you also have a return vent. Return vents have a filter as well. The return vent is the vent that sucks in air that is then recycled through the system. If that vent is clogged, the system will strain, which could cause the unit to short or overheat. This might contribute to your lack of cold air.

Pro Tip: make sure there is no furniture or other obstacle blocking the return vent, as this can cause a similar problem as a clogged vent.

Air filters are not the only part of an air conditioner that is vulnerable to clogs. It is also possible for your drain system in your AC unit to clog and then fill with water. Every AC unit absorbs moisture, which helps make the room more comfortable. This moisture does not, however, simply disappear.

AC units have different drainage systems, but they all expel water through a drainage canal. If the drainpipe is not flushed regularly it can get clogged. Mold and algae can build up, as well as outdoor debris. Check your drainage pipe and make sure it is clear. It may be a good idea to clean it even if it does not appear to be clogged.

If you have an HVAC system then you also have a condenser unit. The condenser unit for your HVAC system has a coil that is mostly exposed to the elements. If the condenser is clean and working well it draws in air. If, however, the unit is blocked – a similar issue can occur just like if the air filter is clogged.

When you notice the exterior of the condenser is dirty, you can try carefully cleaning it yourself using a soft clean brush attachment from a vacuum. This will loosen up and suck up the debris.

If you have a wall unit that is no longer blowing cold air, there is a chance you may have purchased a unit that is not equipped for your living space. If you bought a unit that is designed for a small space and put it in a large room, your unit is working overtime all the time. This can cause your unit to overheat and stop working properly.

Check your unit and verify it is meant for your room size You can easily find this out by measuring the square footage of your room. If the AC unit is too small, you may want to look into purchasing a more suitable unit.

While these are some of the most common reasons your AC is not blowing cold air, there are a plethora of other, less common, sources of this problem. If you cannot locate the reason why your air conditioner is not blowing out cold air, you should call a professional. A professional AC and HVAC repair specialist should be able to diagnose your problem and provide you with the best solution.

After all, AC units do not last forever. In fact you should expect even high quality units to last between 10 and 20 years. You might need a new system, or perhaps a specialized part you likely never knew even existed. Keep in mind some repairs can take several days or even a week, depending on parts availability.