AC Works During The Day But Not At Night – What Could Be Wrong?

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Having a working air conditioner makes life easier, especially during hot summer days. But what happens if the air conditioner fails to work during the night? Don't worry, as we asked experts in the field this question and have answers for you. 

According to professionals, the reason why an air conditioner doesn't work during the night is because it freezes up. Several factors contribute to this, such as poor airflow and low outside temperatures.

In this article, we will further discuss what contributes to your air conditioner freezing during the night and cover preventive measures for freezing and how to defrost the air conditioner if necessary. Continue reading to find out more.

Male technician in overalls and a blue cap repairs an air conditioner on the wall, AC Works During The Day But Not At Night - What Could Be Wrong?

Why AC Isn't Your Working At Night?

Close up of High efficiency modern AC-heater unit

As mentioned earlier, the reason why the air conditioner fails during the night is that certain parts of it freeze over.

Freezing happens when there's airflow circulating inside the unit. Once frozen, it takes a while to thaw these AC parts out, leading to significant damage to the overall system.

Of course, it's also possible that the air conditioner itself is not working properly, and that there is something else in play. In this section, we will discuss the most common possibilities that lead to a failing AC unit at night.

Insufficient Airflow

We stated earlier that not having enough airflow from the air conditioner can cause the unit to freeze up. Dust and dirt are two of the most common causes that lead to obstructed airflow.

Dust and dirt can cause parts of the system to become blocked, causing serious damage to the AC unit in the long run.

It's best to regularly check the filters to see if they need cleaning out. Most of the time, though, you will need to replace them if they get too dirty.

Low Refrigerant Levels

 Engineer checking AC refrigerant level and refilling freon.

The refrigerant is responsible for turning warm outside air to cool air for you to enjoy. So if you notice that your air conditioning unit is having a hard time blowing cool air, then it's highly likely that there's a leak.

This requires immediate attention for a couple of reasons. For one, low levels of refrigerant would cause your air conditioning unit to work harder. In turn, it would further drop the normal temperature inside an AC unit, causing it to freeze over.

The other reason is that a refrigerant leak would pose serious health problems for you and your family. Prolonged exposure to this chemical can lead to long-term health risks. Contact a professional as soon as possible in this situation.

Check out this refrigerant leak detector on Amazon.

Outside Air Temperature

This is something that most homeowners are unaware of. Most AC units can only work efficiently under certain temperatures.

If the temperatures outside are lower than what the manual of your AC unit recommends, there could be a problem down the line. Low outside temperatures can cause the pressure inside the AC unit to drop, leading the system to freeze over.

Stuck Contactor

Another reason why your air conditioner may not be working properly is because of a stuck contactor. This is located on the outside portion of your air conditioning unit.

To check if this is the problem, turn the thermostat off. Then, if the outside portion of your AC unit keeps running, you have a stuck contactor.

If you leave this unattended, it will eventually freeze the entire system. To shut it down, you would have to turn it off via the circuit breaker.

Clogged Condenser Coil

Dirty refrigerator condenser cooling coils covered in dust and pet hair.

Dust and dirt can easily infiltrate the AC system. When that happens, it's normal for a blockage to occur.

When left to accumulate, water will cling to the dust and dirt, and in turn, it would freeze and clog the airways.

Thermostat Issues

Sometimes the problem doesn't lie with your air conditioning unit. If everything is in proper working condition, then the issue may lie with the thermostat.

If you have a faulty thermostat, it can send the wrong signals to your AC unit. This would then cause the system to work harder and eventually freeze over.

To prevent faulty readings, check whether your thermostat needs replacing. If not, you may need to move it somewhere that's not susceptible to drafts and is closer to the middle of your home.

Check out this thermostat on Amazon.

How To Prevent AC From Freezing?

In this section, we will discuss some basic tips and tricks on how you can prevent your AC unit from freezing over. Below are just some of the suggestions that can make your life easier and save you money on repairs in the long run.

Check The Filters

Air conditioner filter

This is one of the things that most homeowners often overlook. It's important to check whether or not you have clogged filters. That's because warm air won't be able to circulate properly inside the system.

If warm air can't circulate properly, the evaporator coils will eventually freeze over. That's why it's best to check the filters at least once every three to six months to ensure optimal efficiency.

Check out these air filters on Amazon.

Clean The Evaporator Coils

Similar to the filters, evaporator coils need cleaning as well. That's because water can stick to dust and debris and freeze. This would cause blockage to occur, which would lead to the entire system freezing.

This also allows you to check the evaporator coils. Any cracks or leaks that you find require immediate attention.

If you want to know how long it takes to replace an evaporator coil, don't worry. We have provided a link to this query below. Make sure to head on over there once you finish reading this article.

How Long Does It Take To Replace An Evaporator Coil?

Empty The Drip Pan

The drip pan is responsible for collecting all the excess moisture from your AC unit. However, it can also be a source of worry.

Make sure to empty the drip pan at least once a month, depending on how often you use your AC unit. If not, the water collected could freeze and prove to be a major stumbling block for your air conditioner.

Schedule Preventive AC Maintenance

If you want to extend the lifespan of your AC unit and prevent the rise of such problems as freezing, it's best to schedule yearly AC maintenance. By doing so, you can keep your HVAC system working at optimal efficiency.

How To Unfreeze An AC Unit?

Before proceeding to defrost your AC unit, the first thing you need to do is check the drip pan. Make sure that it's empty to avoid further problems.

Next, turn the air conditioner off and switch on the fan setting. This allows the frozen coils time to defrost. Additionally, the warm air from the fan helps speed up the process.

Once you've given enough time for your AC unit to defrost, make sure to wipe away any excess moisture. Empty the drip pan again before turning the unit on.

Sometimes all your air conditioning unit needs is time to rest before it starts working at full capacity again.

If defrosting the AC unit doesn't work, it's time to call in the professionals. There may be parts that need replacing, and it's best to leave something like that to the experts.

How Long To Defrost An AC Unit?

close up ice on coil cooler of dirty air conditioner

If you're planning to defrost your AC unit, you should keep in mind that it can take almost a day to unfreeze an air conditioning unit. in some cases, however, it can only take a couple of hours. It all depends on how serious the problem is.

That's why it's best to plan accordingly when you want to defrost your air conditioning unit. After all, the last thing you would want is to be at the mercy of the sweltering heat while waiting for your AC unit to unfreeze.

In Closing 

The reason why your air conditioner isn't working at night is because it's freezing up. Several issues can cause this, including low outside temperatures and poor aiflow.

However, it's also possible that you have a faulty thermostat that causes your air conditioner to fail at night.

It's best to spot any issues of this type early and to schedule yearly maintenance for your air conditioner unit.

If you finished reading through this article, consider the ones below. They provide even more information on related topics that you might want answers to as well.

AC Unit Freezing Up In The Summer; What Could Be Wrong?

Running AC Below 60 Degrees; Is It Safe?

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