Ice on Heat Pump or AC: Normal vs Problem

You're looking at your outdoor unit and notice ice buildup. Should you panic? Usually no - but sometimes yes.

Here's how to tell the difference in 5 minutes.

Normal Ice (Heat Pump Defrost Cycle)

What You'll See

• Light frost or thin ice on coils
• Ice melts within 10-15 minutes
• Liquid drips from unit (normal condensate)
• Cycles on/off naturally

Why It Happens

• Heat pumps reverse cycle to melt ice
• Defrost mode: Runs heating reversed (melts ice)
• Happens 30-60 minutes after startup in cold weather
• Completely normal and designed

What to Do

• Nothing! System fixing itself
• Don't pour hot water on unit (damage risk)
• Give it 15-20 minutes to complete cycle

When This Is Okay

• Temperature outside 30-45°F
• Light frost/thin ice only
• Defrosts within 15 minutes
• Clear water dripping from unit

Problem Ice (True Issues)

Red Flag #1: Heavy Ice Buildup

What you see:

• Thick ice more than ½ inch
• Ice stays on unit more than 20 minutes
• Buildup increases each cycle
• Ice on refrigerant lines/connections

Possible causes:

• Airflow blocked (dirty filter or outdoor debris)
• Refrigerant leak (low charge)
• Faulty defrost sensor
• Thermostat error

Action: Call for service

Red Flag #2: Indoor Unit Freezing

What you see:

• Ice forming on indoor air handler
• Water leaking inside home
• Reduced airflow or no airflow
• Hissing or gurgling sounds

Cause: Usually very low refrigerant or blocked airflow

Action: Turn off system and call immediately (water damage risk)

Red Flag #3: Continuous Ice, No Melt

What you see:

• Ice present even in defrost cycle
• Never melts completely
• Pattern repeating every hour
• System seems stuck

Cause: Defrost cycle not working (sensor issue)

Action: Call for service (system ineffective while frozen)

Red Flag #4: Ice on Electrical Connections

What you see:

• Ice specifically on wiring/connections
• Different from normal unit icing
• Sparking or electrical smells
• Burning odor

Action: Turn off immediately, call for emergency service

DIY Troubleshooting (5-Minute Check)

Step 1: Check Your Filter

• Most common cause of ice buildup
• Blocked filter = restricted airflow
• Causes ice formation on indoor/outdoor coils
• Fix: Replace filter immediately

Step 2: Check Outdoor Unit

• Look around compressor unit
• Is it clogged with leaves/debris?
• Any frost buildup blocking airflow?
• Fix: Gently clear debris (don't use pressure washer)

Step 3: Check Thermostat Mode

• Heat pump in "Cool" mode? (shouldn't have ice)
• System stuck in emergency heat?
• Thermostat showing error?
• Fix: Change mode or reset thermostat

Step 4: Monitor Defrost Cycle

• Watch unit for 20 minutes
• Does ice melt during defrost?
• Listen for reversing valve (clicking sound)
• Does it sound normal?

Step 5: Check Indoor Unit

• Any ice on air handler in basement/attic?
• Water dripping from condensate drain?
• Frozen return air?
• Warning: Stop and call if ice inside

Bay Area Weather & Icing

Coastal Areas (SF, Oakland)

• Rarely cold enough for icing
• Defrost cycles rare
• When ice appears = check filter first

Inland Areas (Concord, Walnut Creek)

• More frequent icing in winter
• Normal defrost cycles expected
• Ice in January/February = usually normal

When Temperature Matters

Outdoor Temp	Ice Likely?	Expected Action
Below 25°F	Yes	Frequent defrost cycles
25-35°F	Very likely	Regular icing/defrost
35-45°F	Sometimes	Occasional defrost
Above 45°F	Rare	Investigate if present

Differences: Heat Pump vs AC Unit

Heat Pump (Winter Heating)

• Normal: Frequent defrost cycles
• Ice expected on outdoor coil
• Refrigerant reverses to melt ice

Central AC (Summer Cooling)

• Normal: No ice at all
• Outdoor coil stays dry
• If ice appears in cooling mode = problem

When to Call Galaxy

Call if:

• Ice doesn't melt within 20 minutes
• Heavy thick ice buildup
• Ice on indoor unit/connections
• Reduced airflow despite ice melting
• Same icing pattern recurring daily

Don't call if:

• Light frost/ice during cold weather
• Melts naturally within 20 minutes
• System works normally after defrost
• Just one or two cycles per day

Quick Maintenance Tips

Prevent icing:

1. Change filter every 90 days (every 60 if pets)
2. Keep outdoor unit clear of debris
3. Ensure 2 feet clearance around unit
4. Check condensate drain quarterly
5. Schedule professional maintenance annually

Energy Impact of Ice

System with ice buildup:

• Efficiency reduced 20-40%
• Energy bills higher
• Less heating/cooling output
• Equipment stressed

Why it matters: Addressing icing saves money in multiple ways

Still Unsure?

Call for a free ice assessment. Better safe than sorry with refrigerant systems.

Schedule Ice Diagnosis | Call (925) 578-3293