Carbon Monoxide: The Invisible Killer in Your Home
A cracked heat exchanger can leak lethal CO into your home silently. Learn the symptoms, detector placement, and exactly what to do when your alarm sounds.
🔥 Safety
🔴 EMERGENCY REFERRAL LINE
24/7 Emergency HVAC Repair Near You
Review the safety precautions below, then connect with an independent HVAC provider for assistance.
Call Now — (844) 582-1795
Disclosure: This website is a referral and information service. The line is free to call; we may connect you with independent HVAC providers and may receive compensation if you call. Calls may be routed to an independent provider network and may be recorded. Providers set their own diagnostic and after-hours fees (see typical fees). We do not provide HVAC services directly.
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How It Works
1
Describe Your Situation
Tell us what's happening so we can connect you with the right independent HVAC provider for your situation.
2
Share Key Details
We collect your location, system type, and issue details so we can share them with a provider in your area.
3
Provider Connection
We connect you with an available independent provider in your area. Response time varies by location and demand.
24/7, Same-Day, and After-Hours HVAC Service
HVAC failures don't wait for business hours. Cool Call Pro routes your call to an independent HVAC provider that offers emergency response — including 24 hour HVAC repair, same-day AC repair, after-hours furnace service, and weekend heat pump calls. Availability varies by ZIP code and current demand.
24 Hour HVAC Repair
Some independent providers in the Cool Call Pro network offer round-the-clock emergency response, depending on your area. An on-call technician may be dispatched overnight for total heat loss in winter, total AC failure during heat advisories, water leaks threatening equipment, or a carbon monoxide detector alarm (after 911 has been called). Overnight dispatch fees and minimum service charges are set by the individual provider, not Cool Call Pro.
Same-Day Emergency Service
Whether same-day service is possible depends on local provider availability, the time you call, the distance to your ZIP code, and current demand. When you call the service line, the provider gives you an arrival window based on their current queue.
After-Hours, Weekend & Holiday
Some providers offer emergency HVAC service after normal business hours, on weekends, and on federal holidays. Expect a surcharge for weekend, holiday, or overnight dispatch — the exact amount is set by the individual provider. Per our cost guide, a diagnostic or service-call fee typically runs $65–$150, and night, weekend and holiday calls add $100–$300 on top of the repair cost. Some providers credit the diagnostic fee toward the repair; ask when you call. Confirm the diagnostic fee and any minimum service charge with the provider before they arrive.
This page covers six HVAC emergencies, with immediate step-by-step actions for each. For gas leaks, carbon monoxide, fire, or electrical shock — call 911 first. For all other HVAC failures — total heat or AC loss, water leaks, or sudden strange noises — use the number above to connect with an independent provider in your area. Do not attempt to open, repair, or modify any HVAC equipment yourself.
Rotten Egg / Sulfur Smell
IMMEDIATE ACTIONS — IN ORDER:
- Evacuate immediately — leave all doors open as you go
- Do NOT use any electrical switch, plug, or light inside — not even to turn them off
- Do NOT use your phone or any device while still inside the building
- Do NOT light matches or lighters, and do not start a car nearby
- Do NOT try to find the leak or shut off any gas valve, meter, or appliance
- Go to a neighbor's house or the street — well away from the building
- From outside: Call 911 FIRST, then call your gas utility company. Use your phone only once you are safely outside (or borrow a neighbor's phone)
- Once emergency services are on the way, call the service line: (844) 582-1795
- Do NOT go back inside until the gas utility or emergency responders say it is safe
Source: PGW natural gas safety guidance. Not sure whether it is gas or carbon monoxide? Read Gas Leak vs CO Leak: Telling Them Apart.
Furnace Failure in Cold Weather
WHILE YOU WAIT FOR A PROVIDER:
- Check thermostat — set to HEAT, 68°F+
- A provider can check your breaker and furnace filter — do not open electrical panels yourself
- Keep interior doors open to distribute remaining heat
- Use electric space heaters (NOT gas, NOT oven)
- Freezing weather forecast? Tell the dispatcher the heat is out, and see the American Red Cross frozen-pipe guidance
- Protect pets and elderly — relocate if needed
Air Conditioning Failure in Heat
HEAT SAFETY — DO THIS NOW:
- Turn off AC at thermostat to prevent motor damage
- A provider can check your breaker and electrical components — do not open panels yourself
- Close blinds/curtains to block solar heat gain
- Use portable fans — move hot air out at night
- Drink cool water / use cold packs on neck/wrists
- Check on elderly neighbors — heat stroke risk
- Do NOT open AC unit panels yourself
CO Detector Alarm Going Off
SILENT KILLER — DON'T WAIT:
- Evacuate everyone immediately
- Leave door open; go outside to fresh air
- Do NOT re-enter for any reason
- Call 911 — CO is a medical emergency
- Count all people and pets
- Symptoms (per the CDC): headache, dizziness, weakness, upset stomach, vomiting, chest pain, confusion
- Do NOT re-enter until cleared by fire dept.
Water Pooling Around Unit
PREVENT FURTHER DAMAGE:
- Turn off HVAC at thermostat immediately
- Stay away from the water and the equipment; leave breakers and switches alone for the technician
- Use towels/buckets — do NOT use a vacuum
- A technician will check the condensate drain pan and line
- Document water damage with photos for insurance
- Do NOT touch wiring/electrical near standing water
Banging, Screaming, or Grinding
WHAT THE SOUNDS MEAN:
- Banging/Clunking: Loose or broken part — SHUT OFF NOW
- Screaming/Squealing: Belt or bearing failure — call today
- Clicking (won't start): Relay or capacitor issue
- Humming (no airflow): Capacitor or motor issue
- Rattling: Loose panel, debris, or duct issue
- Rule: If the sound is sudden and loud — turn the system off at the thermostat
Emergency HVAC Repair by System Type
Every HVAC emergency is different. Here's what a provider looks for when you call about a specific system failure.
Emergency AC Repair
A provider checks for problems such as a failed capacitor, a burned-out compressor contactor, low or lost refrigerant, or a frozen indoor coil. A single-component repair (capacitor or contactor replacement) may be completed on the first visit if the technician has the part on hand. Compressor or evaporator-coil replacement is a larger repair that may require a return visit. See our cost guide for typical repair ranges.
Emergency Furnace Repair
A provider checks for problems such as ignitor failure, flame sensor fouling, gas valve faults, or failed blower-motor capacitors. For any carbon monoxide detector alarm, evacuate and call 911 before calling an HVAC provider. ENERGY STAR suggests talking to a contractor about replacement once a furnace is more than 15 years old, so for an older furnace ask the provider to explain repair-versus-replace options before you approve a major repair.
Emergency Heat Pump Service
Two heat pump emergencies to watch for: total loss of heat in winter (possible causes include a failed defrost cycle, refrigerant loss, or a reversing valve issue) and a unit that runs but cannot maintain setpoint during a heat advisory. Heat pumps share most diagnostic paths with central AC, but the reversing valve adds complexity. A provider should verify refrigerant charge, capacitor health, defrost-cycle operation, and the reversing valve before recommending a major repair.
When to Call 911 vs. (844) 582-1795
Call 911 FIRST if:
- You smell gas AND can't evacuate
- Anyone has CO poisoning symptoms
- Smoke or fire from HVAC unit
- Electrical sparks or shock occurred
- Someone is injured or unconscious
Call (844) 582-1795 for:
- Complete loss of heat or AC
- HVAC making dangerous noises
- Water leaks from unit
- Thermostat or control failures
- Warm spots, ice on unit, or weak airflow
Connect with an HVAC Provider
We will try to connect you with an independent HVAC provider who can help. Learn more about HVAC repair costs →
Call Now — (844) 582-1795Response times vary by location and demand.
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Emergency HVAC — Frequently Asked Questions
Quick answers to the most common questions before you call.
Click or tap a question to expand.
Response times depend on your location, time of day, and current demand. We
cannot guarantee specific arrival windows, but we connect you with the nearest available
provider as quickly as possible. Call to get an estimated timeframe for your area.
Cool Call Pro connects homeowners with independent HVAC professionals
across many parts of the United States. Coverage varies by location. Call (844) 582-1795 to
find out if a provider is currently available near you.
Emergency repair costs vary widely based on the issue, parts needed, your
location, and the time of service. Cool Call Pro does not set or guarantee pricing — cost is
determined by the independent provider. Per our cost guide, a diagnostic or service-call fee typically runs $65–$150, and night, weekend and holiday calls add $100–$300 on top of the repair cost. Some providers credit the diagnostic fee toward the repair; ask when you call.
No. Cool Call Pro is a referral and information service that connects
homeowners with
independent HVAC providers. We do not perform repairs ourselves and are
not responsible for the work performed by referred providers.
Call 911 immediately. Gas leaks and carbon monoxide are
life-threatening emergencies that require your local fire department or gas utility — not an
HVAC provider. Evacuate your home first, then call 911 from outside. Only after emergency
services have responded should you connect to a provider for follow-up HVAC service.
The referral line is open 24/7. Some independent providers in the Cool Call Pro network offer 24 hour emergency HVAC service, depending on your area. Overnight and early-morning dispatch availability depends on your ZIP code and the providers currently on-call. Call (844) 582-1795 to confirm a provider is available for your location.
Same-day AC repair depends on local provider availability, the time you call, the provider queue, distance to your ZIP code, and seasonal demand. The provider confirms a specific arrival window when you call.
Emergency, after-hours, and weekend calls typically carry a surcharge on top of the standard diagnostic fee. The exact amount is set by each independent provider, not Cool Call Pro. Per our cost guide, a diagnostic or service-call fee typically runs $65–$150, and night, weekend and holiday calls add $100–$300 on top of the repair cost. Some providers credit the diagnostic fee toward the repair; ask when you call. Ask the provider for the diagnostic fee, after-hours surcharge, and any minimum service charge before they arrive.
Total loss of heat in cold weather, total loss of AC during heat advisories, water leaks from your HVAC system, burning or rotten-egg smells, sudden mechanical noises, and any carbon monoxide detector alarm. Gas leaks and CO alarms require 911 first. Non-emergencies (thermostat glitches, mild comfort issues, routine maintenance) can wait for a scheduled appointment.
Some independent providers in the Cool Call Pro network offer emergency HVAC service on weekends and federal holidays, depending on your area. Expect a weekend or holiday surcharge on top of the standard diagnostic fee. Confirm the total estimated charge with the provider before they dispatch.