why is my ac freezing

What To Do When Your AC Unit Freezes Up

  • AC units can freeze up for many reasons at any time of year, including summer
  • Common causes include blocked airflow, mechanical issues, and dirty coils
  • Some issues can be fixed at home, while others require professional attention

When the AC unit freezes up, homeowners naturally begin to panic. It can be very worrying to see icy or frosty buildups all over your system, and in the worst cases, entire blocks of ice can begin to form. Clearly, these are not good signs, and it can be particularly disconcerting if your AC unit freezes up in summer when the sun is shining and temperatures are warm.

It can really ruin your day to discover the AC unit frozen, and your home might start getting unbearably hot. Luckily, even though this is a serious issue, there are plenty of ways in which it can be fixed quite quickly in order to get your frozen AC unit back on track and your home cooled down once more. This guide will go over some common causes of freezing AC systems and how they can be fixed.

When Your Ac freezes up, the Problem might be in Broken Airflow 

One of the most common reasons why an AC unit freezes up is because of broken or blocked airflow. Air conditioner units require a steady and continuous flow of air throughout them, as this is why keeps moisture flowing and prevents any water vapor from settling on the interior coils and components, where it may freeze. 

If the airflow gets broken, condensation appears on the coils and then that can turn into ice over time. The longer this problem is left without professional air conditioning repair, the worse the situation can become, as the ice and frost buildups will grow over time, eventually enveloping the entire system and making the blockage even worse.

How to fix it:

It’s highly likely in situations of broken or blocked airflow that the AC filters have become clogged. So the filters will need cleaning or changing. The unit will first need to be switched off and given some time to defrost. After a couple of hours, you can switch the fan back on for an hour and then switch out the filter for a fresh one. This should solve the issue.

Mechanical Problems or Refrigerant Leaks

frozen AC

If your AC unit freezes up, it might also be the case that you’re dealing with either a mechanical issue or a refrigerant leak. AC units are quite complex machines, with a lot of parts and systems on the inside that keep them functioning smoothly and correctly. Those different parts can all suffer mechanical faults and failures over time, due to various factors. Fans can break or stutter and parts can become loose or less effective, for example.

Your unit also relies on a special fluid, known as refrigerant, which plays a vital role in allowing the AC unit to transfer heat out of the air in your home and cool down your rooms and living spaces. If this fluid leaks out and the levels drop too low, the unit can become far less efficient and this is a common cause of an AC unit freezing up in summer.

How to fix it: 

The process for fixing mechanical problems or refrigerant leaks will depend on the exact cause and nature of the problem. It’s not really something that you can handle on your own unless you have extensive AC experience, so it’s best to call in professionals for some emergency AC service.

They’ll be able to carry out checks and tests of your unit to identify the issue and repair it. In some cases, especially with refrigerant leaks, they may even recommend that you buy a new AC altogether. They might also be able to advise you on useful AC maintenance methods to reduce the risk of further issues in the future.

Cool Summer Nights, Can the AC Unit Freeze up in Summer? 

Absolutely, it’s more than possible for your AC unit to freeze up in the summer months, and this is actually aair conditioning freezes up surprisingly common time for people to report AC issues. It all depends on the conditions at the time. In the day, the sun might be shining and the air might be warm, but in the evenings in some locations, temperatures can drop down quite low, beyond the 60-degree limit that most AC units comfortably operate at.

If the temperatures drop too low, the AC unit won’t be able to continue operating as normal. This can cause it to work inefficiently, and there’s a chance that the AC unit freezes up outside overnight while it tries to cope with the cool conditions.

How to fix it:

The key to fixing this particular issue is avoiding it in the first place. Most ACs will have programmable settings and features that allow them to shut down automatically when the temperatures drop under 60 degrees. This way, if it gets too cold, the AC can simply switch itself off and you won’t have to worry about a thing. 

If your unit doesn’t have this kind of setting, you may just have to keep an eye on the weather forecast and predicted temperatures and turn your AC off manually if the temperatures are expected to drop down too low.

Dirty Coils 

Another possibility when your AC unit freezes up is that the coils are too dirty and need to be cleaned. The air conditioner coils play a huge role in the heat transfer process, which is basically how an air conditioner cools down your home, but even the slightest bit of dirt or dust on these coils can interfere with their operations. 

Usually, what happens is that the coils pull the moisture out of the air in order to remove heat energy from it. The water then appears as condensation on the coils and drips off into a drip pan below. However, if there is dirt on the coils, this process can become more inefficient and the coils won’t be able to absorb the water quickly enough, causing frost and ice to form and build up over time.

How to fix it:

Again, the best way to deal with this problem is to prevent it from happening in the first place by making sure that your AC unit is cleaned and maintained on a regular basis. Getting regular checkups from an HVAC professional can help with this, but if it’s already too late, a professional will be able to disassemble your unit, thaw the ice, and clean the coils to get your system working once more.

Condensate Drain Line Issue

damages ac freezesAnother possible cause for concern when an AC freezes up is the condensate drain line. This is part of the AC’s built-in drainage system, and it’s responsible for taking water away from the unit and out of the home. Water builds up in the drip pan while the unit is switched on, as explained above, and then flows out and away via the drain line

If this line gets clogged, the water in the tray can start to overflow and excess moisture can gather inside the unit itself, on the coils and other components, where it may freeze, due to the low temperatures of the refrigerant in the system. It’s therefore vital to try and avoid any clogs in the drain line.

How to fix it:

This is one of the most common ac problems, and it’s quite simple to fix. The key is to take a look at the condensate drain line and remove any blockages or clogs. You can use a wet/dry vacuum to remove anything that might be blocking the way, or call in a professional to use more advanced tools and equipment.

Damaged Fan

The fan is another very important part of your AC system. It works to blow the cold air out around the home and push the warm air away, outside of the property. Essentially, its main duty is to “suck” the hot air away, and the cold air then automatically moves to fill the space left behind by the hot air. 

Of course, if the fan gets damaged and stops working correctly, the airflow for your entire AC unit can become interrupted. This can lead to moisture remaining inside the system and gathering on the coils, as explained earlier on, where it can freeze into ice and developing into large, frosty buildups.

How to fix it:

A damaged fan will need professional attention. A professional repairman will be able to disassemble your unit safely and take a look at the fan to find out what the problem is. The fan might need repairing or it could have to be replaced entirely with a new one.

Bottom Line

As this guide shows, there can be many possible explanations when an AC unit freezes either inside or outside the home and whenever this kind of issue occurs, it’s best to consult with HVAC professionals who can get your system up and running once again.