HVAC Troubleshooting Guide
Step-by-step guides to identify HVAC issues. Learn what you can fix yourself and when to call a professional. Available 24/7 for emergencies.
⚠️ Emergency Situations - Act Immediately
Gas Smell
Leave immediately. Call gas company from outside. Do NOT use electrical switches.
Burning Smell
Turn off system immediately. Call for emergency service if smell persists.
Sparking/Electrical Issues
Turn off system at breaker. Do not attempt DIY. Call for emergency service.
Carbon Monoxide Alarm
Evacuate immediately. Call 911. Do not re-enter until cleared by professionals.
Common HVAC Problems
Click any issue for detailed troubleshooting steps
AC Not Cooling
Your AC is running but not cooling the house. Common causes and fixes.
Symptoms
- • Warm air from vents
- • AC runs constantly
Quick Fixes
- ✓ Check/replace air filter
- ✓ Verify thermostat settings
Call a Pro If:
If quick fixes don't work or you hear unusual noises
Furnace Not Heating
Your furnace won't turn on or isn't producing heat. Diagnosis steps.
Symptoms
- • No heat from vents
- • Furnace won't start
Quick Fixes
- ✓ Check thermostat batteries
- ✓ Check/replace filter
Call a Pro If:
If you smell gas, see sparks, or pilot won't stay lit
HVAC Strange Noises
Banging, squealing, grinding, or clicking sounds from your HVAC system.
Symptoms
- • Banging/clanking
- • Squealing/screeching
Quick Fixes
- ✓ Turn off system
- ✓ Check for loose panels
Call a Pro If:
Most noises indicate mechanical issues requiring professional diagnosis
High Energy Bills
Unexplained increase in heating or cooling costs. Efficiency troubleshooting.
Symptoms
- • Bills 20%+ higher than usual
- • System runs constantly
Quick Fixes
- ✓ Replace air filter
- ✓ Check for duct leaks
Call a Pro If:
For efficiency audit, duct sealing, or system tune-up
Uneven Temperatures
Some rooms too hot, others too cold. Balancing and airflow issues.
Symptoms
- • Hot/cold spots
- • Second floor always hot
Quick Fixes
- ✓ Check vents are open
- ✓ Adjust dampers
Call a Pro If:
For duct inspection, zoning solutions, or system rebalancing
AC Freezing Up
Ice forming on your AC unit or refrigerant lines. Causes and solutions.
Symptoms
- • Ice on outdoor unit
- • Ice on copper lines
Quick Fixes
- ✓ Turn off AC immediately
- ✓ Let ice melt (2-4 hours)
Call a Pro If:
If freezing recurs after filter change - indicates refrigerant or airflow issue
Thermostat Problems
Thermostat not responding, incorrect readings, or system not following schedule.
Symptoms
- • Blank display
- • Wrong temperature reading
Quick Fixes
- ✓ Replace batteries
- ✓ Check circuit breaker
Call a Pro If:
If thermostat replacement is needed or wiring issues suspected
Poor Air Quality
Dusty home, musty odors, allergy symptoms, or humidity issues.
Symptoms
- • Excessive dust
- • Musty/moldy smell
Quick Fixes
- ✓ Replace filter with higher MERV
- ✓ Clean vents and returns
Call a Pro If:
For air quality testing, UV light installation, or dehumidifier setup
DIY vs. Call a Professional
Know when it's safe to troubleshoot yourself
✓ Safe for DIY
- • Replacing air filters (monthly)
- • Changing thermostat batteries
- • Checking/resetting circuit breakers
- • Clearing debris from outdoor unit
- • Opening closed vents and registers
- • Programming thermostat schedules
✗ Call a Professional
- • Anything involving refrigerant
- • Electrical repairs or wiring
- • Gas furnace repairs
- • Compressor or motor issues
- • Ductwork modifications
- • Recurring problems after DIY attempts
Troubleshooting FAQ
Frequently Asked Questions
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