HVAC Troubleshooting Center
Expert solutions for common heating and cooling problems. Get step-by-step diagnosis guides, DIY fixes, and know exactly when to call a professional.
Emergency Situations
Call emergency services immediately if you:
- Smell gas or suspect a gas leak
- Hear your carbon monoxide alarm
- See flames or smoke from your HVAC system
- Notice electrical sparking or burning smells
❄️ Winter/Heating Problems
- 🟠Furnace Not Heating
- 🔴Furnace Not Turning On
- 🟠Furnace Short Cycling
- 🟠Furnace Pilot Light Won't Stay Lit
- 🟡Furnace Making Loud Noise / Banging
- 🟠Heat Pump Not Working
- 🟠Heat Pump Not Heating / Blowing Cold Air
- 🟠Heat Pump Icing Up / Freezing in Winter
- 🟡Heat Pump Running Constantly / Not Cycling Off
- 🟡Thermostat Problems
- 🟠Thermostat Not Responding / Blank Screen
- 🟡Poor Airflow
- 🔵High Energy Bills
- 🟡Strange Smells from HVAC
- 🔵Uneven Temperatures
☀️ Summer/Cooling Problems
- 🟠AC Not Turning On
- 🟠AC Freezing Up
- 🟠AC Leaking Water
- 🟡AC Making Noise
- 🟠AC Short Cycling
- 🟠AC Not Cooling / Not Blowing Cold Air
- 🟡AC Running Constantly / Won't Shut Off
- 🟠Heat Pump Not Working
- 🟡Heat Pump Running Constantly / Not Cycling Off
- 🟡Thermostat Problems
- 🟠Thermostat Not Responding / Blank Screen
- 🟡Poor Airflow
- 🔵High Energy Bills
- 🟡Strange Smells from HVAC
- 🔵Uneven Temperatures
Air Conditioner Problems
AC Not Turning On
🟠Air conditioner completely unresponsive with no fan, no sounds, or display showing but nothing happens.
AC Freezing Up
🟠Ice buildup on indoor coils, outdoor refrigerant lines, or complete unit freezing preventing cooling.
AC Leaking Water
🟠Water dripping, pooling, or leaking from indoor AC unit or ceiling below air handler.
AC Making Noise
🟡Unusual sounds from AC unit including banging, grinding, squealing, hissing, or clicking noises.
AC Short Cycling
🟠AC turns on and off repeatedly in short bursts instead of running proper cooling cycles.
AC Not Cooling / Not Blowing Cold Air
🟠Air conditioner runs but produces warm or room-temperature air instead of cooling properly.
AC Running Constantly / Won't Shut Off
🟡Air conditioner runs continuously without cycling off, even when target temperature is reached.
Furnace Problems
Furnace Not Heating
🟠Furnace runs but produces no heat, or blows cold air instead of warm air.
Furnace Not Turning On
🔴Furnace completely unresponsive with no sounds, no ignition attempt, or no blower activation.
Furnace Short Cycling
🟠Furnace starts and stops in short bursts instead of running full heating cycles.
Furnace Pilot Light Won't Stay Lit
🟠Pilot light on gas furnace goes out repeatedly or won't stay lit after relighting.
Furnace Making Loud Noise / Banging
🟡Furnace produces unusual or loud noises including banging, rumbling, screeching, or whistling sounds.
Heat Pump Problems
Heat Pump Not Working
🟠Heat pump fails to heat or cool, won't switch modes, or runs but produces no temperature change.
Heat Pump Not Heating / Blowing Cold Air
🟠Heat pump runs but only blows cold air in heating mode, fails to produce warm air, or stays in cooling mode.
Heat Pump Icing Up / Freezing in Winter
🟠Outdoor heat pump unit covered in heavy ice or frost that doesn't melt, defrost cycle not working.
Heat Pump Running Constantly / Not Cycling Off
🟡Heat pump runs continuously without cycling off, never reaches set temperature, or runs non-stop even in mild weather.
Thermostat Problems
General HVAC Problems
Poor Airflow
🟡Weak air coming from vents, some rooms get little or no airflow, or reduced air pressure throughout home.
High Energy Bills
🔵Unusually high electric or gas bills compared to previous months or years, excessive HVAC energy usage.
Strange Smells from HVAC
🟡Unusual odors from vents including musty, burning, chemical, rotten egg, or other strange smells.
Uneven Temperatures
🔵Some rooms too hot or cold, temperature differences between floors, hot and cold spots throughout home.
HVAC Calculators & Tools
Planning a repair or replacement? Use our free calculators to estimate costs and sizing.
When to DIY vs. Call a Professional
✓ Safe for DIY
- •Replacing air filters
- •Cleaning outdoor condenser unit
- •Resetting circuit breakers
- •Thermostat battery replacement
- •Clearing vents and registers
- •Checking thermostat settings
! Call a Professional
- •Refrigerant leaks or recharging
- •Electrical wiring issues
- •Compressor or motor replacement
- •Gas line work or leaks
- •Ductwork installation or major repairs
- •Anything involving high voltage
Need HVAC Help?
Can't fix it yourself? Find experienced local HVAC contractors for professional repairs.