How Do I Fix My Frozen Air Conditioner?

What to Do When Your Air Conditioner Freezes Up

Delafield Air Conditioning Repair Services Checking Frozen AC UnitYour air conditioner is frozen. Now your house is hot, and you’re sweating. That’s not good. How did this happen? 

1. Airflow Is Restricted

The air conditioner is designed to take heat from your house to decrease temperature. If there isn’t enough airflow over the evaporator coil, the heat exchange cannot happen as designed. The coil is too cold and drops to freezing levels. Humidity in the air makes contact with the coil and moisture condenses on the surface. The condensation freezes on the coils, and you’ve got a frozen air conditioner.

This is the most common reason window and central air units freeze up. Impeded airflow could result from either a dirty filter, blocked ductwork or dirty or blocked evaporator coil.

2. Air Conditioning Unit is Low on Refrigerant

Your air conditioner is liable to freeze when refrigerant levels are too low. Even when there is less refrigerant in your system, it must expand the same amount. With more expansion comes a cooler temperature. Once again, the coil falls below freezing and moisture from the air condenses and freezes on the coils.

Remember—if this is the case, your air conditioner is leaking refrigerant! Some HVAC technicians will try to convince you air conditioners occasionally need to be “recharged” and bill you for frequent service calls. Don’t fall for this scam. If your unit is low on refrigerant, it is leaking and needs repairs.

3. Air Conditioner Freezing Up at Night? The Temperature Is Too Low!

You don’t want to run the air conditioner all day, every day. Not only because it costs a pretty penny, but because it can cause serious problems with your unit.

Pay attention to the temperature—if it falls too low while your unit is running, it may freeze. Lower outside temperatures decrease pressure in the unit, and, much the same as in the case of low refrigerant, lower pressure means the coils get too cold. Moisture from the air condenses and freezes on the coil.

You’ll run into problems when the temperature reaches about 62°F. To be safe, shut off the air conditioner when outside temperatures reach 65°F at night.

4. A/C Parts are Broken or Malfunctioning

This is potentially the worst option for your piggy bank.

Check to see if the refrigerant line is kinked. Is the fan dinged or out of balance? 

If the refrigerant line, blower fan or motor is broken beyond repair, you will likely need to enlist the aid of an HVAC technician and pay for replacement parts. If the damage is bad enough, you may need to consider replacing the unit entirely.

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How to Fix a Frozen Air Conditioner

You don’t want to have to call an HVAC technician out to your house if you can help it. If your A/C unit is frozen and you want to attempt to fix it yourself, take the following steps:

  1. Turn off the air conditioner.
  2. Allow the coil to defrost.
  3. Check the air filter. If it is dirty or clogged, replace immediately.
  4. Check the evaporator coil. If it is dirty, clean it using compressed air, commercial cleaners or a water/detergent mix.
  5. Check ductwork for obstructions, leaks, bends or disconnections.
  6. Ensure no registers are blocked.
  7. Remove registers and look inside duct. If it appears dirty, have your ductwork cleaned by professionals.
  8. If your air conditioner is still frozen, it means your refrigerant is low or the blower or refrigerant line is damaged. Contact the Waukesha HVAC experts at Hot Point.

Avoid Air Conditioner Freeze-Ups by Taking Appropriate Preventative Measures

Waukesha AC Maintenance Tech Replacing Filters on Air Conditioner

Of course, the best way to avoid having to do DIY repairs on your air conditioner in a scorching hot house is to perform regular inspections on your unit before a problem arises. Take any of the following precautions and you greatly decrease the chance of ever running into this problem:

  • Replace the air filter every 2-3 months
  • Inspect the integrity of your ductwork
  • Make sure no registers are blocked
  • Check the coil for debris and dust
  • Only run the unit when the temperature outside is above 65°F

But if all your preparation is for naught and your unit freezes up, you know who to call. The HVAC professionals at Hot Point have years of experience troubleshooting, fixing and replacing air conditioners in Delafield, Oconomowoc, Hartland and the rest of Waukesha County. Whether it's a window or central air units, we'll repair or replace it any time, day or night. Contact us today for an HVAC service quote.

Our Oconomowoc cooling experts are available for your emergency air conditioner repair 24 hours a day. Call our service line now at 262-567-9505.