Las Vegas Heat Alert: AC not cooling can reach dangerous temps within 2-3 hours

AC Running But Not Cooling in Las Vegas?

When your AC runs but doesn't cool properly during Las Vegas 110°F+ summers, your home can become dangerous fast. Here's how to diagnose and fix the problem.

Top 8 Reasons Your AC Isn't Cooling (Las Vegas Edition)

1

Dirty Air Filter (Most Common)

Las Vegas dust clogs filters 2-3x faster than other cities. Reduces airflow by up to 50%.

✅ DIY Fix: Replace filter immediately

2

Low Refrigerant / Leak

Refrigerant leaks cause 35% of cooling failures. Look for ice on copper lines.

⚠️ Pro Needed: EPA-certified technician required

3

Dirty Condenser Coils

Desert dust buildup on outdoor unit coils reduces cooling capacity by 30%.

✅ DIY Fix: Gentle hose rinse (power OFF)

4

Frozen Evaporator Coil

Ice buildup prevents heat absorption. Caused by airflow restrictions or low refrigerant.

✅ DIY Fix: Turn off AC for 4 hours to thaw

5

Undersized AC Unit

Las Vegas requires 25% more cooling capacity than moderate climates. Your unit may be too small.

📊 Check: BTU capacity vs square footage

6

Leaky Ductwork

30-40% of cooled air escapes through duct leaks in Las Vegas attics (140°F+).

⚠️ Pro Needed: Duct sealing and insulation

7

Failing Compressor

Compressor runs but doesn't build pressure. Common in units 12+ years old in extreme heat.

🚨 Pro Needed: High-cost repair ($1,500-$3,000)

8

Thermostat Malfunction

Wrong temperature reading or poor placement (near heat sources) causes inadequate cooling.

✅ DIY Fix: Check placement and calibration

5-Minute Diagnostic: What's Wrong With My AC?

🌡️ If AC blows WARM air:

Likely causes: Low refrigerant, compressor failure, or reversing valve stuck

→ Call professional immediately (refrigerant leak or major component failure)

💨 If AC blows WEAK cool air:

Likely causes: Dirty filter, duct leaks, or undersized unit

→ Try: Replace filter, check vents for blockages, verify all registers are open

❄️ If you see ICE on pipes:

Likely causes: Low refrigerant, dirty coils, or restricted airflow

→ Try: Turn off AC for 4 hours, replace filter, then restart

🔄 If AC runs CONSTANTLY:

Likely causes: Undersized unit, thermostat issue, or significant air leaks

→ Check: Thermostat setting, door/window seals, and attic insulation

Try These DIY Fixes First (Before Calling a Pro)

1. Replace Your Air Filter

In Las Vegas, filters should be replaced monthly (not every 3 months like other cities).

  • Use MERV 8-11 filters for dust protection without restricting airflow
  • Check filter every 2 weeks during summer
  • Cost: $15-25 per filter (saves $200+ in repair calls)

2. Clean Your Outdoor Unit

Desert dust reduces cooling by 20-30% when buildup is heavy.

  1. Turn OFF power at breaker box
  2. Remove debris within 2 feet of unit
  3. Gently spray coils with garden hose (not pressure washer)
  4. Straighten bent fins with fin comb ($10 at hardware store)
  5. Wait 30 minutes before turning power back on

3. Check All Vents and Registers

Blocked vents reduce cooling effectiveness by 25% per room.

  • Open all supply registers (don't close more than 20% of them)
  • Ensure furniture isn't blocking airflow
  • Check return vents for obstructions

4. Verify Thermostat Settings

Incorrect thermostat settings cause 15% of "not cooling" complaints.

  • Set to "COOL" mode (not "AUTO" or "FAN")
  • Lower temp setting by 5°F below current room temp
  • Replace batteries if digital display is dim
  • Ensure thermostat isn't in direct sunlight or near heat sources

When DIY Won't Cut It - Call a Professional If:

  • You see ice buildup on refrigerant lines after filter change
  • Outdoor unit fan not spinning (capacitor or motor failure)
  • Hissing or bubbling sounds (refrigerant leak)
  • Circuit breaker trips repeatedly
  • Strange odors from vents (burning, musty, or chemical smells)
  • AC older than 10 years and never serviced
  • Water pooling around indoor unit
  • DIY fixes didn't improve cooling after 24 hours

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