What should you do first?
For a carbon-monoxide alarm or suspected exposure, get everyone outside to fresh air and call 911. If you smell or hear leaking gas, leave immediately and contact 911 or the local gas authority from outside. For electrical smoke or fire, leave and call 911. Do not stay inside to troubleshoot.
Safe first checks
Before requesting repair
- From a safe location, identify whether the issue is loss of cooling, loss of heat, water, unusual sound, odor, or power.
- Check the thermostat display and settings only when there is no gas, smoke, CO, or electrical danger.
- If safe, note the outdoor temperature and whether children, older adults, or medically vulnerable people are affected.
- Keep the equipment off after repeated breaker trips, smoke, strong burning odor, or water near electrical parts.
Stop and call
Warning signs that need more caution
- Carbon-monoxide alarm or symptoms such as dizziness, nausea, or confusion
- Gas odor or hissing near fuel equipment
- Smoke, sparking, or active burning smell
- Water contacting energized equipment
- No cooling in extreme heat or no heat in freezing conditions
Possible causes
What may be behind the symptom
Life-safety event
CO, gas, fire, and electrical hazards are emergency-service situations first. HVAC diagnosis comes only after authorities say the property is safe.
Total system failure
Controls, power, ignition, motors, compressors, or safety devices can stop all heating or cooling.
Escalating equipment damage
Repeated breaker trips, severe vibration, ice, or uncontrolled water may indicate a fault that should not be repeatedly restarted.
Professional diagnosis
What a technician may inspect
- Safety of the work area before equipment testing
- Electrical supply, controls, safeties, and fault history
- Heating ignition and combustion components where applicable
- Motors, compressor, airflow, coils, and drainage
- What can be stabilized now versus what requires parts or follow-up
Cost context
What can affect repair price?
- The system type, capacity, age, and accessibility
- The failed component and whether compatible parts are available
- Diagnostic or service-call fees in the local market
- After-hours timing and current provider availability
- Refrigerant type, electrical work, and any additional testing required
Common questions
Frequently asked questions
What counts as an HVAC emergency?
Conditions involving gas, carbon monoxide, smoke, fire, electrical danger, water on electrical equipment, or dangerous indoor temperatures may be emergencies. Gas, CO, and fire hazards require emergency services first.
Is emergency repair available 24 hours?
Not necessarily. Availability varies by location, provider, and time. This site does not claim 24/7 service unless that coverage is specifically confirmed.
Should I turn the HVAC system off if it smells burnt?
If you can do so without approaching smoke, sparks, or danger, stop using the system. Leave and call 911 if there is active smoke, fire, or an immediate electrical hazard.
Can I stay in the home when a CO alarm sounds?
No. CPSC guidance says to get outside immediately and then call 911. Do not re-enter until responders say it is safe.