Why is my Air Conditioner freezing?

Many air conditioner owners have had to deal with a frozen air conditioner at some point. If your air conditioner seems to be running less effectively than usual, you should take a look ‘behind the scenes’ to see the inner workings. If you can see ice on any outer parts of the unit, or if the inner parts are dripping water, this means that your air conditioner is frozen. Some easy indicators that your unit is freezing up include:

  • Soaked filter
  • Solid ice block around the evaporator coil
  • Thick layer of ice coating the copper piping

There are a number of reasons why your air conditioner may be freezing up -

Dirty Filter

Your air conditioner needs sufficient airflow to run properly – this is hindered when your air filter is dirty. A dirty filter has to be cleaned or replaced, otherwise it can freeze your air conditioner and cause other serious problems:

  • A blocked filter causes your air conditioner to work harder than needed. This decreases the lifespan of your unit as it burns out the motor – if this happens you will be forced to replace your entire air conditioning unit.
  • A dirty filter disturbs the air quality in your home. The filter’s purpose is to remove allergens from the air, such as dirt, dust, pollen, mould and mildew.

The filter is a critical part of your air conditioner, and problems will keep presenting themselves if you’re not maintaining it correctly and frequently. You should have your system checked and maintained seasonally or biannually by a professional.

It’s Too Cold Outside

This becomes more of a problem when seasons change. When it gets cold outside, your air conditioner is more likely to freeze. It’s important to know that your air conditioner has to cool the air to 6 or 7 degrees less than you’d like your house temperature to feel. This means that if it’s cold one night, and your thermostat is set low, your air conditioner might be frozen by the morning.

Freon is Low

It may seem illogical, but low levels of refrigerant will cause the evaporative coils in your air conditioner to get too cold, which in turn will freeze up your air conditioner. You can usually rectify low Freon levels by recharging, but the low level itself is often a sign of problem. If you notice low Freon levels, you should get a professional to come and check your system. Freon is a dangerous chemical which should only be dealt with by licensed contractors. You should never try to fix a leak or refill Freon on your own.

Faulty Fan

If the fan in your air conditioner isn't working properly, air can’t circulate through. Improper airflow can create ‘cold spots’ that turn condensation into ice blocks.

Not Knowing When to Turn Off

The contractor in your air conditioner can become blocked by insects, dirt and debris, which stops the system from knowing when to turn off. If the system runs all day and night, it can swiftly seize up with ice.

Blocked Vents

If your vent is blocked, it will reduce the airflow to the evaporator coil, leading to freezing. Similar to a dirty filter, such an obstruction hinders sufficient air circulation. This in turn causes cold air to concentrate in areas and ice is formed.

Too Old

Air Conditioning have a finite lifespan, and their efficiency lowers as they grow older. If your system is ten years old and has been causing you problems, it’s likely time to start looking for a new system.