Why is My Air Conditioner Freezing Up? - Ernst Heating & Cooling

Why is My Air Conditioner Freezing Up?

A/C freezes up

The temperature in Hamel, IL, is soaring, but your air conditioner is frozen. While you may think a little ice in the A/C unit is simply giving it a cool head start, you’re sadly mistaken. A frozen A/C unit means something went wrong in the cooling process. Ignoring it will not make your problem melt away. Ernst Heating & Cooling can help you troubleshoot the problem and ensure your home’s A/C stays ice-free, as it keeps your home cool.

A quick study: How does A/C work?

To understand why your home’s A/C is freezing, it’s important to first get your brain around how A/C works. A lot of people assume the A/C unit is simply blowing warm air over ice, making it cooler during these hot August days. But A/C is a little more complicated than that. Instead, the system works in a continuous loop, pulling heat out of your indoor air and sending the remaining cool air back through your home.

How does it do that? The A/C unit has an evaporator coil filled with cold refrigerant fluid. When warm air is sucked through the return vents in your home, it blows over the evaporator coil. The evaporator coil absorbs the heat, turning the liquid refrigerant into a hot gas. The remaining cool air gets sent back inside, while the hot refrigerant gas makes its way outside the house to the compressor. The aptly named compressor squeezes the warm refrigerant and makes it even hotter. This vapor now moves through the condenser, where the heat is released into the outside air, and the refrigerant cools and changes back to its original liquid form. The refrigerant returns to the evaporator coil and begins its job again.

The good news? If your home’s A/C is running well, you don’t have to worry about understanding the cooling process. But if your home isn’t getting as cool as it should, you may be tempted to peek around at the A/C unit. If you notice ice has formed around it, you have a problem.

What causes an A/C unit to freeze

Simply put, A/C units can freeze when there is little or no airflow. Without that warm air flow blowing over the evaporator coil, the refrigerant never has a chance to turn into gas and become compressed even further. Moisture can build up on the coils and freeze. The refrigerant cannot achieve the correct pressure inside the coils, and your A/C can’t do its cool job.

Here’s what we commonly see as the culprit in the reduced airflow puzzle:

Clogged air filters. Your HVAC system usually includes an air filter designed to protect components from dust and dirt in the air. Most air filters need to be changed regularly. Otherwise, they become too dirty and impede airflow. Ensure you’re changing your air filter according to the manufacturer’s instructions.

Damaged blower fans. Remember, you’re trying to draw the warm air over your unit’s evaporator coils to start the heat removal process. If the blower fan isn’t moving the air efficiently – or at all – the evaporator coils can’t grab the heat, and the refrigerant stays cold. Freezing may be the ultimate result.

Clogged condensate lines. During the cooling process, water vapor can be pulled from the surrounding air and condensed into liquid form on the evaporator coil. That’s one reason you’ll notice that an air-conditioned room doesn’t feel as humid as the outdoor air. This liquid goes through the condensate line to a drain or outdoors. If the moisture isn’t draining, it can accumulate around the evaporator coils and freeze over.

Low refrigerant. If your system is low on refrigerant, it interferes with the pressurization process and contributes to a frozen unit.

What to do if your home’s A/C freezes

If you find ice around your home’s A/C unit, you must thaw it out. Turn off the power to the A/C and let the warm air do its job. Don’t be tempted to break the ice manually – you risk damaging the expensive components contained within your HVAC unit.

You must also do some detective work to determine why the A/C is freezing. Check your air filter. If it’s dirty, replace it. Make sure your vents aren’t clogged. If the A/C is working again, you may have solved the problem. Or, you may have done a temporary fix.

Call in the experts at Ernst Heating & Cooling

At-home troubleshooting is a good first step, but a faulty A/C unit calls for professional help. The trained HVAC professionals can quickly diagnose and repair the unit, bringing your family the cool relief you crave. Want to avoid the problem in the first place? When you schedule regular HVAC maintenance, you can reduce your chances of a frozen A/C unit. During these biannual, annual tune-ups, the Ernst HVAC techs will thoroughly inspect your system, adding refrigerant and looking for problems that can lead to a frozen A/C unit at the most inconvenient time. You can even save money and headaches by signing up for the Ernst Comfort Plan, which offers a furnace and an A/C tune-up each year, as well as discounts on repairs and priority scheduling. You can learn more about A/C maintenance and the Ernst Comfort Plan by scheduling your appointment at 618.217.1836. Do you prefer online scheduling? You can request it here.

Remember, A/C is supposed to be cool, not frozen. If you’re having A/C trouble or notice ice around your unit, call Ernst Heating & Cooling now for service in just hours!

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