Top 2 Most Common Causes of a Frozen Coil

Wednesday, May 26th, 2021

Everything’s bigger in Texas, including our summer heat. As we brace for triple digit weather and praise Jesus for the blessing of air conditioning, we want to help you stay cool and comfortable this summer. But a cooling system that’s not cooling can really put a damper on things. We’ve spoken with many customers this week as the temperatures have risen and heard many waking up to find their coils in either their indoor or outdoor unit have frozen solid. That is no bueno. But how does that happen? What makes your cooling system turn in to an ice cube in a matter of hours? After over 20 years of being your home’s best friend, here are the three most common causes we’ve found for a frozen coil.

  1. You have a dirty filter

If we had the Ten Commandments of HVAC, we would make “Change Your Filters” number one. Dirty filters can cause a whole host of issues, like a frozen coil.

Your cooling system needs plenty of air flow to create plenty of cool air. When a filter is clogged with dirt, hair, dust and more it restricts the air flow. This causes the temperature of the coil to drop and the coil to freeze.

Depending on your filter and your home environment (smoking, pets, etc.), you may need to change it anywhere from every 30-90 days. We recommend checking your filter to make sure it’s not clogged every 30 days and then changing it accordingly.

Long Story Short: A dirty filter restricts air flow to your coil, causing it to freeze. Change your filters regularly to provide plenty of air flow.

Handy Tip: To help you remember the last time you changed your filter, mark the date you replaced it on the edge of the filter.

  1. You have a refrigerant leak in your coil

What is refrigerant you ask? It is the chemical that runs through the coils, changing the pressure and temperature of the air in order to absorb the heat. If there is a leak in the coil this lowers the pressure in the coil and lowers the temperature of the coil. Since the coil can no longer absorb the heat from the air properly, your cooling system will need to run longer to meet the set temperature leading to the coil getting colder and colder until it is frozen solid.

If you have a leak in your coil, you may find the simpler solution is just to have your service professional fill it back up with refrigerant. However, leaving your system to leak refrigerant into the atmosphere is actually a major no-no and can have adverse effects on the ozone layer and your utility bill due to your system having to work harder to maintain the temperature in your home. If you compare the cost of refilling the refrigerant versus replacing the coil, you may find it is far more economical to go ahead and replace the coil. We do not want you to lose money on a temporary fix instead of investing money in a permanent fix.

Long Story Short: A frozen coil may mean you have a leak in your coil. You will want to get this fixed quickly as continuing to refill the coil with refrigerant could cost you more money long term versus replacing the coil now.

Figure SEQ Figure \”ALPHABETIC A-Frozen coil in the indoor unit of a home.
  1. What should you do if you find your coil is frozen?

1. Turn the system off. Your thermostat has an “OFF” setting. By turning the system off, you can help prevent further damage to the system and help the coil start to thaw so a service professional can get right to work on finding out why it froze in the first place. Keep an eye on the water that might be created from the thawing to avoid water damage.

2. Check your filters. If you find your filter is dirty, go ahead and change it. Give it a little while for the coil to thaw. If the system starts to cool your home again, you should be in the clear.

3. If after changing the filter your system does not begin working properly, call Daffan, your home’s best friend. Our service professional will be able to diagnose exactly why your coil has frozen and help provide you with a solution.

4. Join the Daffan Maintenance Club. Regular maintenance can allow our service professionals to catch many of the small problems that may cause your coil to freeze and help you avoid costly repairs. And you get special discounts and guaranteed service day and night.

As your home’s best friend, we want to help you stay comfortable all year round and avoid costly repairs. If you ever have questions or concerns regarding your cooling and heating system, our team is ready to answer your call and serve you and your home.