Triage by symptom
Use the table below to triage the most common after-hours hvac pros emergencies. Each row tells you what to do before a pro arrives — these are the actions that protect your property, your family, and your bill while dispatch is en route.
| Symptom | What to do right now |
|---|---|
| No heat in freezing weather | Check the thermostat batteries and breaker first. If those are fine, call a 24/7 HVAC tech — frozen pipes become a secondary emergency within hours. |
| No cool in extreme heat (vulnerable household) | Move at-risk family members to a cool space. A common cause is a failed capacitor — typically a same-day fix. |
| Burning smell from vents | Shut the system off at the thermostat and breaker. Could be a seized blower motor or wiring fault. Do not run the system until inspected. |
| Carbon monoxide alarm sounding | Leave the home immediately, call 911. After the fire department clears the home, an HVAC tech needs to inspect the heat exchanger before re-use. |
| Refrigerant leak (oily residue, hissing) | Shut the system off at the thermostat. Refrigerant leaks should not be allowed to run dry — that destroys the compressor and turns a $400 fix into a $4,500 fix. |
How fast will a hvac pro actually arrive?
Emergency HVAC response is typically 60–120 minutes during extreme weather. Most metros have dedicated 24/7 dispatch. Capacitor and contactor failures are the single most common after-hours fix. The fastest way to dispatch the closest available hvac pro is the free FixNearMe quote form — your request is routed instantly to up to three nearby 24/7 pros, and the first to respond is usually at your door within the hour.
What an after-hours hvac pro should cost
Emergency dispatch fees range from $90 to $180 in most metros, and that fee is typically credited toward the repair if the pro performs the work that night. The repair itself is priced like a normal job — see our hvac cost guide for the line-by-line averages. Be wary of any pro who quotes a "we're out anyway" overnight call without a written estimate; emergency does not mean cash-only.
What to ask before they start
Even in an emergency, a 30-second checklist will save you hours of headache later: confirm a current state license, ask for a written estimate before they touch anything, ask whether the dispatch fee credits toward the repair, and ask for a 24-hour follow-up window so you can confirm the fix held. The full hvac pro hiring checklist walks through every question and the red flags to watch for.