Is it an HVAC emergency?
Start with a safety check, then explore a few simple things you can check before requesting service.
Gas smell, CO alarm, smoke or immediate danger? Leave the building and call 911 from safety.
First, check for warning signs
Do you smell gas, hear a carbon monoxide alarm, see smoke or sparks, or notice a strong electrical burning smell? Is anyone experiencing possible carbon monoxide symptoms such as headache, dizziness or nausea?
General homeowner guidance, not a diagnosis or emergency monitoring service. Answers stay on this page. Reviewed September 17, 2026.