No Heat
Needs service soonThe furnace may be running, but the home is not warming up.
All HVAC Problems We Service
Browse every furnace and AC symptom below. See likely causes, safe checks you can try, urgency levels, and links to city-specific repair pages.
Not sure what's wrong?
Start Step-by-Step DiagnosisFurnace Symptoms
No heat, burner issues, strange smells, uneven rooms, or rising heating bills.
Won't Turn On
Needs service soonThe furnace does not respond when heat is requested.
Yellow Burner Flame
Needs service soonA burner flame that looks yellow instead of mostly blue can signal combustion trouble.
Burning or Gas Smell
EmergencyA burning smell or gas odor near the furnace may indicate a safety problem.
Hot and Cold Rooms
Can troubleshoot firstSome rooms heat normally while others stay too cold or too warm.
Sudden High Energy Bills
Plan serviceHeating costs jumped without an obvious weather or usage change.
Furnace symptom
No Heat
No heat usually points to ignition, thermostat, airflow, or furnace safety-shutdown trouble.
Thermostat setting or control issueIgnition or flame-sensing failureTripped breaker or power interruptionRestricted airflow from a clogged filter
Safe things to check first
- Set the thermostat to Heat and above room temperature
- Check the furnace switch and electrical breaker
- Replace a clogged air filter if needed
- Confirm supply vents and returns are open
Call now if
- The furnace will not start at all
- The breaker keeps tripping
- The furnace starts and shuts off repeatedly
- Indoor temperature is dropping quickly
Furnace symptom
Won't Turn On
A furnace that will not start often points to power loss, thermostat trouble, or an internal control issue.
Power interruption or tripped breakerThermostat failure or wrong settingsControl board or safety switch issueFuse or disconnect issue
Safe things to check first
- Set the thermostat to Heat and raise the setpoint
- Check the furnace switch near the unit
- Inspect the breaker panel for a tripped breaker
- Replace thermostat batteries if applicable
Call now if
- The system stays completely dead after basic checks
- The breaker trips again immediately
- You hear clicks but the unit never starts
Furnace symptom
Yellow Burner Flame
An abnormal burner flame should be treated carefully because combustion or venting problems can become unsafe.
Dirty burnersCombustion or ventilation problemImproper gas-air mixtureBurner alignment or service issue
Safe things to check first
- Turn the system off if the flame looks abnormal or unstable
- Check carbon monoxide alarms in the home
- Move to fresh air if anyone feels unwell
Call now if
- The flame is mostly yellow or rolling
- A carbon monoxide alarm has activated
- You notice soot, fumes, or headaches
Furnace symptom
Burning or Gas Smell
Strong gas or burning odors should be treated as urgent until proven otherwise.
Gas leak or combustion issueElectrical overheatingDust burning off after first startupMotor or wiring problem
Safe things to check first
- If you smell gas, leave the home and avoid switches or flames
- Shut the system off only if it is safe to do so
- If the smell is light dust at first seasonal startup, monitor briefly
Call now if
- You smell gas or rotten eggs
- The smell is strong, sharp, or getting worse
- A carbon monoxide alarm has activated
- You see smoke, sparks, or scorching
Furnace symptom
Hot and Cold Rooms
Uneven heating usually points to airflow balance, duct delivery, or return-air problems.
Airflow imbalanceDuct restrictions or leaksDirty filterSystem sizing or zoning issue
Safe things to check first
- Replace a dirty filter
- Make sure vents and returns are fully open
- Check that furniture or rugs are not blocking airflow
- Confirm thermostat settings are stable
Call now if
- Some rooms get almost no airflow
- The imbalance is getting worse
- The furnace is running constantly without improving comfort
Furnace symptom
Sudden High Energy Bills
Higher heating bills usually point to longer runtimes, airflow restriction, or declining efficiency.
Dirty filter or restricted airflowDeclining system efficiencyThermostat or control issueLonger runtimes from mechanical wear
Safe things to check first
- Replace the filter
- Compare thermostat schedule to recent settings
- Check for closed vents and blocked returns
- Look for obvious air leaks around doors and windows
Call now if
- Bills jumped sharply with no weather explanation
- The furnace is running much longer than usual
- Comfort has also declined
AC Symptoms
Warm air, ice, leaks, noise, weak airflow, uneven cooling, or high summer bills.
Weak or Warm Air
Needs service soonThe AC is running, but the air is weak, warm, or not cooling properly.
Short Cycling
Can troubleshoot firstThe AC turns on and off too often without finishing a normal cooling cycle.
Water or Ice Around Unit
Needs service soonWater leaks or ice buildup usually point to airflow, drain, or cooling-cycle trouble.
Low or No Airflow
Can troubleshoot firstAir is barely moving from the vents, or some areas are getting almost none.
Loud Noises
Can troubleshoot firstBanging, screeching, rattling, or other unusual noises may signal mechanical wear.
Bad Smells
Can troubleshoot firstMusty, burning, or unusual odors through the vents may indicate mold, drainage, or electrical issues.
Hot and Cold Rooms
Plan serviceSome rooms cool well while others stay warm or uncomfortable.
Sudden High Energy Bills
Plan serviceCooling costs jumped without an obvious increase in weather or usage.
AC symptom
Weak or Warm Air
Weak or warm air usually points to airflow restriction, an outdoor-unit problem, or a cooling-cycle issue.
Restricted airflow from a clogged filterOutdoor unit not running correctlyRefrigerant or cooling-cycle issueThermostat setting issue
Safe things to check first
- Set the thermostat to Cool and lower than room temperature
- Replace a dirty filter
- Make sure supply vents and returns are open
- Check whether the outdoor unit is running
Call now if
- The system blows warm air continuously
- The outdoor unit is not running
- Cooling has dropped off sharply
- The system runs nonstop without cooling
AC symptom
Short Cycling
Short cycling often points to airflow restriction, thermostat trouble, or overheating protection.
Restricted airflowThermostat placement or control issueOverheating or protection shutdownElectrical or capacitor issue
Safe things to check first
- Replace a dirty filter
- Check that vents and returns are open
- Make sure the thermostat is not near a heat source or direct sunlight
Call now if
- The unit starts and stops every few minutes
- The home never reaches the set temperature
- You hear unusual noises during startup or shutdown
AC symptom
Water or Ice Around Unit
Water or ice around the unit usually points to drainage trouble, restricted airflow, or a frozen coil.
Restricted airflow from a dirty filterCondensate drain problemFrozen evaporator coilLow airflow or cooling-cycle issue
Safe things to check first
- Turn cooling off if ice is building up
- Replace a dirty filter
- Check whether vents and returns are open
- Watch for active indoor leaking around the air handler
Call now if
- Ice is visible on refrigerant lines or indoor components
- Water is leaking indoors
- Cooling performance has dropped sharply
- Ice returns after replacing the filter
AC symptom
Low or No Airflow
Low airflow usually points to filter restriction, blower trouble, or duct-related airflow loss.
Dirty filterBlower or fan issueDuct restriction or leakageClosed or blocked vents
Safe things to check first
- Replace a dirty filter
- Open all supply vents and returns
- Move furniture away from vents and returns
- Check whether airflow is weak everywhere or just in some rooms
Call now if
- There is almost no airflow anywhere in the home
- The system runs but air barely moves
- Weak airflow is paired with warm air or ice buildup
AC symptom
Loud Noises
Unusual AC noise usually points to loose components, fan wear, or motor/compressor trouble.
Loose hardware or panelFan or blower wearMotor or bearing issueDebris in the unit
Safe things to check first
- Shut the unit off if the sound is severe
- Check for loose exterior debris around the outdoor unit
- Note whether the noise happens at startup, during running, or shutdown
Call now if
- The sound is sudden, loud, or metallic
- Cooling performance also dropped
- The system shakes, stalls, or trips power
AC symptom
Bad Smells
AC odors usually point to moisture, contamination, or electrical heat inside the system.
Drainage or moisture issueBiological growth in damp areasElectrical overheatingDirty filter or coil contamination
Safe things to check first
- Replace a dirty filter
- If the smell is burning, shut the system off
- Check for obvious standing water near the indoor unit
Call now if
- The smell is burning, sharp, or getting worse
- The smell is paired with poor cooling or noise
- You suspect electrical overheating
AC symptom
Hot and Cold Rooms
Hot and cold rooms usually point to distribution imbalance, duct issues, or room-specific heat gain.
Duct imbalance or leakageWeak airflow in certain branchesSolar gain or insulation differencesFilter or blower airflow problem
Safe things to check first
- Replace a dirty filter
- Check for blocked vents or returns
- Keep interior doors positioned consistently
- Note which rooms are warmest and when
Call now if
- Some rooms get almost no cool air
- Comfort problems are getting worse
- The AC is running long without balancing temperatures
AC symptom
Sudden High Energy Bills
Higher cooling bills usually point to airflow loss, reduced efficiency, or extended runtime.
Restricted airflow from a dirty filterDeclining cooling efficiencyLonger runtimes from cooling lossThermostat or control issue
Safe things to check first
- Replace the filter
- Review thermostat schedule and fan settings
- Make sure vents and returns are open
- Check that windows and doors are sealing well
Call now if
- Bills rose sharply and comfort also dropped
- The system runs much longer than normal
- Cooling feels weak while costs climb
City page directory
All symptom pages by city
Find the city-specific page for any symptom across our full service area.