It’s 80 degrees outside. You’re burning up inside, but when you go to check your AC, part of it looks frozen. What is going on here? Let’s discuss eight reasons why your AC unit might be freezing up.

1. A dirty furnace filter:

When your filter gets dirty, it’s more difficult for air to move through the evaporator coil, causing the temperature of the refrigerant to drop because the air is not absorbing the cooling. As a result, your AC’s evaporator coil slowly starts to ice over. The condensation that runs down your coil and into the condensate drain will start to freeze, and the longer you keep it running, the more it freezes.

If you can’t seem to remember the last time you changed your air filters, well, chances are that you have found your problem. Alternatively, home construction, sheetrock, woodcutting, or even painting causes fine dust to get sucked in by the return air and plug up your filter very quickly.

2. Having too many vents closed off:

You should ensure that all your vents are open and nothing is blocking the return grills. Imagine your vents are like your air filter. If your air filter is clogged or your vents are closed, air won’t be able to move through the system properly.

3. Unit low on freon:

Typically, the temperature of the freon that’s going inside the evaporator coil is about 38 degrees. The temperature and pressure correlate, which means the temperature decrease when the pressure is low. When the temperature drops below 32 degrees, the condensation that your evaporator is collecting will free. The longer you run the system, the more it freezes.

4. Thermostat set too low:

Setting your thermostat too low can also cause freezing. The lowest set point for most air conditioners is about 67 degrees. If you go around 60 or something, there’s a very high chance that your air conditioner is going to freeze.

5. Faulty blower motor:

Another reason your unit is reason could be a faulty blower motor. In other words, your motor might not be working inside the furnace either because it’s burnt out or the capacitor is weak or dead. This means no air is going across the evaporator coil, causing it to freeze very quickly.

6. Failing control board in the furnace:

If the control board in the furnace is failing, your whole system will run slower. For example, if the board is not sending power to the blower motor, the motor won’t turn on and move the air.

7. Restricted metering device:

Another reason your AC might be freezing up could be that the metering device at the evaporator coil is clogged. This can happen due to contaminants inside of a freon loop. Remember, the metering device has just a tiny hole and can get blocked easily. So, if this is happening and freon is not getting through that hole, it will lower the freon pressure.

8. Clogged evaporator coil:

If your evaporator coil is clogged or your filters are often dirty, whatever dust gets through those filters will eventually settle at the evaporator coil, restricting the airflow.

Now that we know what can cause the AC unit to freeze, let’s discuss how we can save ourselves from trouble.

Firstly, change your air filter. Debris such as dust, pollen, dirt, and other allergens build up over time. Most people change their filters every three to four months.
You should schedule regular maintenance to check the coolant levels. If you have a coolant leak, call a professional because the coolant chemicals can be toxic.
Get an airflow inspection. Blocked or restricted airflow is one of the major reasons cooling and heating systems do not work properly.
Clean the evaporator coils.

If you start noticing any issues with your HVAC unit, don’t hesitate to give the Bacon team a call!

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