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If you notice ice or frost on your HVAC unit, it could be a sign that your AC is freezing up. If the issue is left unchecked, the system stops cooling correctly. You may notice that it blows warm air, doesn’t move air at all or never turns off.
Why Is My AC Freezing Up?
Common reasons for an AC unit freezing up include:
- Restricted airflow due to an issue with vents, dirty filters or blockages
- Low refrigerant levels
- Problems with evaporator coils or other parts
What to Do When Your AC Unit Freezes Up Inside: Before Calling a Pro
If your AC unit starts freezing up, you can take these steps to address the problem:
- Turn off the AC: Turn your AC unit off of “cool,” and ensure it’s not on “heat.” The goal is to give the system a break and let the evaporator coils return to a normal temperature.
- Turn the fan on: This allows air to flow through the system to help move things along.
- Give it time to thaw: You’ll need to wait for your system to thaw out, and this can take some time. Depending on how frozen the unit was, you may need to wait up to a few hours for it to thaw completely.
- Check and replace the air filter: While you’re waiting for ice to melt off your unit, handle a few basic HVAC maintenance tasks. Check and replace your filter. If you have a reusable filter, this is a great time to wash it. You can wait for it to dry before putting it back in place.
- Check all your vents and the drain line: Blocked vents and drain lines can cause AC lines to freeze, so it’s essential to double-check these areas. Look for visual obstructions, ensure vents aren’t blocked by furniture and vacuum or carefully clean vents, registers and lines.
- Clean up any water: Look around the air handler and other indoor elements of your HVAC system. If ice has thawed in or around them, you may find water on the floor. Clean it up to avoid moisture damage or mold. You can also proactively place a large pan under these areas to catch water as it drips.
- Test your unit and watch for warning signs: Once the unit has thawed completely, turn it back on. If it comes on normally, that can be a good sign. Check areas where ice had previously built up frequently to ensure your AC isn’t freezing up again.
When to Call an HVAC Professional if Your AC’s Freezing Up
If your unit doesn’t thaw out after following the steps above, it may be time to call in a professional for help. You might also want to schedule AC repair services if your unit freezes up again shortly after you thaw it out. If you’re having to thaw your AC out periodically, it can be a sign that something isn’t working properly.
How to Keep Your AC From Freezing in Summer or Winter
To keep your outside AC unit from freezing up in summer, change your air filters regularly, ensure supply vents aren’t blocked and schedule routine professional maintenance before the season heats up.
The same advice applies to preventing your outside AC unit from freezing up in winter. You’ll also want to keep the outside components from getting covered with debris, snow or ice. If you’re outside shoveling your walkways, consider whether you can knock snow away from the HVAC system.
