Every system makes some noise. A new or different one is worth paying attention to. Here's a rough guide.
Usually normal
- A click when the system starts or stops: relays and the thermostat doing their job.
- A soft whoosh as the furnace burners light.
- Ticking as ducts warm up and cool down.
- A whoosh and a pause from a heat pump in winter: it's defrosting its outdoor coil, and you may see a little steam. That's normal.
Worth a call
- Squealing or screeching: often a motor bearing or a worn belt.
- Grinding: a motor or a fan in trouble. Turn it off.
- Rattling or banging: something loose, or a fan blade hitting something.
- A loud bang when the furnace lights: gas building up before it ignites. Have it checked soon.
- Hissing or bubbling at the outdoor unit: can be a refrigerant leak.
- Humming with nothing starting: often a failed capacitor or a motor that can't turn.
- Repeated clicking with no start: the system is trying and failing to light or start.
Turn it off and call
Grinding, burning smells, or anything that sounds like metal on metal: turn the system off at the thermostat to prevent more damage, and call us at 805-965-6326. After-hours emergency service is available by phone.