Why Does My Air Conditioner Freeze Up? | AC Repair In York, PAIf you see ice on your air conditioner, there’s a problem with the coolant inside the system. It froze on the coils and affected the moisture around them. There are a few different reasons why this happens. No matter the cause, you should address it right away to prevent further damage. 

It’s more common on window units. Or, at least, it’s more notable on them. But, it can happen with a central air condenser, too. And, in those cases, it’s not always as obvious. You may need to look down into the unit to notice it. Or, there’s only ice build up on the lines leading from the unit to the house. 

For the more technically-minded out there, we’ll get into a little more detail about how the AC freezes over. Then, we’ll talk about:

  • What Causes It
  • What To Do 
  • How To Prevent It

You can follow the steps we outlined if this happens to the air conditioner in your York, PA home. But, you’ll need a professional to make sure there’s no lasting damage. And that it won’t happen again. So, once you’ve gotten things under control, call us here at Air Comfort Technologies. We provide reliable, expert air conditioner service and repairs for homes across Central Pennsylvania. 

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What Causes An Air Conditioner To Get Ice On It?

We outlined the general explanation above. Now, here’s a little more nitty-gritty:

An air conditioner works by passing warm air over coils with very cold refrigerant, or coolant, in them. The refrigerant cools the air and allows the system to transfer the warmth outside. At the same time, it’s blowing that now-cool air back into your house. 

But, this is a closed system and needs to remain that way. If that coolant gets out of the loop for any reason, it causes the problem we’re discussing here. The refrigerant is so cold that it will freeze over the coil and any moisture around it. There’s always moisture in the air, and the summer is the most humid time of the year. Therefore, it doesn’t take much for that ice to build up. 

So, what can cause this problem?

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Three Reasons For A Frozen Air Conditioner

The three main reasons the coolant can freeze over the coil are:

  1. Obstructed Airflow
  2. Dirty Coil
  3. Refrigerant Leak

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Obstructed Airflow


Dirty Air Filter HVAC Repair in Hanover, PAIf the AC is on, warm air needs to be flowing through it. Otherwise, the system gets out of balance. That can result in the coolant breaking out of the usual process and freezing over the coil.

The most common cause of this is a dirty air filter. The filter is there to prevent dust, dirt, and debris that’s in the air from entering the system. But, you need to change it every month. Otherwise, too much buildup on it prevents air from getting through. 

Or, a foreign object could be obstructing the airflow. It’s often something outside — maybe a critter or some trash — that’s made its way into the system. And, it’s blocking the air. 

Dirty Coil 

When the coil inside the system has dirt on it, the coolant can’t reach the warm air passing over it. You may notice warm air coming into the house. Or, at least, cooling that’s not as cool as you want. Either way, this imbalance can cause the refrigerant to freeze over. 

Refrigerant Leak

Finally, there’s a simple leak somewhere. The coolant found a way out of its closed loop. Once the refrigerant gets exposed to the air, it causes the ice you can see outside the unit.

How To Prevent A Frozen Air Conditioner

heater tune-up in Dover, PAThe bad news is there’s not too much you can do to prevent an air conditioner from freezing over. The good news is that you can do two simple things to reduce the chances of it happening significantly. 

First, as we mentioned before: change the filter every month. This way, you don’t end up with a clogged filter that blocks air from getting through. Less buildup means less dust and dirt that can force its way through and dirty up the coil. 

The other is to get an air conditioner tune-up once a year. It’s a quick, inexpensive process that can save you a lot of time, money, and aggravation in the long run. With basic AC maintenance, you’ll have a tech check all the levels, clean inside the system, and replace any worn-out or broken parts. With this simple service, your air conditioner will be ready for whatever the summer throws at it. 

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What To Do If Your Air Conditioner Freezes Over

If you notice ice on your air conditioner, turn off the system. Yes, you’ll be hot and uncomfortable. But, you’ll prevent any further damage. If the system’s out of balance, it’s likely locked up inside. That could mean a crucial moving part — maybe the blower or fan — is trying to move but can’t. Eventually, it will break. 

After that, it could take a day or so for the ice to thaw. If it helps, you can run the “Fan Only” setting on your thermostat. It won’t provide cooling, but it will at least move the air around in your house. 

In the meantime, call a professional to look over the system. If it’s a leak, they’ll need to repair it and recharge the system. Or, if there’s any other damage, you want them to address it right away before it gets worse. 

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Call Air Comfort Technologies for AC service and repairs in York, PA, Dover, Camp Hill, and across Central Pennsylvania. We have an excellent reputation with plenty of five-star reviews, and we’ll get your home cool and comfortable again as fast as possible. 

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