Why Is There Frost or Ice on My AC? | How to Fix a Frozen AC Unit

AC Froze Up

AC Frozen up? Finding frost or ice on your air conditioner during a hot summer day in Colorado is an unexpected and frustrating problem. However, it's more common than you might think. Running your AC frequently and at colder temperatures increases the chances of it freezing. If you're in Denver, Centennial, Fort Collins, or the surrounding areas and notice ice on your HVAC unit, promptly addressing the issue is crucial.

How to Identify a Frozen AC Unit

The most obvious sign of a frozen AC unit is visible ice on any part of the HVAC system. However, other indicators include:

  • Lack of Cool Air: Ice may be the culprit if you feel warm air coming out of your supply vents instead of cool air.
  • Hissing Sounds: A hissing sound from your unit can also indicate a problem. Immediate action is required to prevent further damage.

Steps to Defrost a Frozen AC Unit

Defrosting your AC unit can take an hour to more than a day. Acting quickly can prevent additional damage and minimize downtime without cool air. Follow these steps to defrost your unit:

Step 1: Turn OFF Your AC

Although it's hot, turning your AC off is necessary to prevent damage to the compressor. Set your thermostat from COOL to OFF to begin the defrosting process.

Step 2: Switch the Fan to ON

Turning the HVAC fan to ON will blow warm air over the frozen coils, accelerating defrost. Ensure the fan is set to ON and not AUTO, as continuous airflow is required.

Ready to find your dream home in Colorado?
Let us help you. Call or Text Kenna Real Estate at 303-955-4220 to get personalized assistance from our expert real estate agents. Find out what your home is worth in today's market.

Step 3: Identify the Cause

Investigate the underlying reasons for your AC freezing up. Common causes include:

  • Dirty Air Filter: Clogged air filters restrict airflow, causing the coils to get too cold and ice over. Replace air filters at least once a month. This is one of the biggest reasons your AC may freeze up. 
  • Dirty Evaporator Coils: Dirt and grime on the coils restrict airflow, similar to a dirty filter. Regular maintenance is essential.
  • Leaking Refrigerant: Low refrigerant levels cause pressure drops, allowing moisture to freeze around the coils. A refrigerant leak requires professional attention.
  • Other Issues: Problems like collapsed ducts, weak blowers, or closed valves can also lead to freezing. A professional diagnosis may be needed.

Step 4: Monitor the Situation

As your unit defrosts, look for water damage from overflowing drain pans or clogged condensation drains. Use towels around the unit to manage any excess water. Once the ice melts and the unit is dry, you can turn your AC back on. Monitor for continued issues over the next few days.

Preventing Future Freezes of Your AC

Regular maintenance is critical to preventing your AC from freezing. Ensure air filters and evaporator coils are clean, check for refrigerant leaks, and address any component issues promptly.

Internal Links and External Resources

For more tips on maintaining your home, check out our Home Maintenance Tips page. If you need professional HVAC services, contact our trusted HVAC Partners. Contact Us for a List of HVAC Technicians.


Following these steps and performing routine maintenance, you can keep your AC running smoothly all summer.

For professional HVAC services in Denver, Centennial, Highlands Ranch, or the surrounding areas, contact us at Kenna Real Estate. Our experts can help you find a qualified HVAC contractor on our list of referrals who can diagnose and fix any issues with your AC unit, ensuring you stay relaxed and comfortable.

Contact Kenna Real Estate 303-955-4220

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Post a Comment

(303) 955-4220