Thermostat and switch
Thermostat on heat and above room temperature. The furnace service switch near the unit must be on.
Furnace not working or stopped heating?
A furnace that will not start, keeps shutting off or blows cold air usually has an ignition, airflow, power or control problem. Check the thermostat, switch, breaker and filter, then call 833-877-1717. If you smell gas, leave first. RepairNowUSA connects the request. An independent HVAC technician does the repair.
Am I in the right place?Yes for a gas, oil or electric furnace that will not turn on, short-cycles, blows cold air, or makes new noises or smells.
Is this urgent?Yes in cold weather or with vulnerable people inside. Gas smell or a CO alarm: leave and call 911 or the gas utility.
What do I do next?Do the checks below, then call 833-877-1717 with the ZIP code and what the furnace does.
Pilot light or igniter trouble: furnace ignition repair. Electric furnace: electric furnace repair. Building fully without heat: no heat.
RepairNowUSA editorial review · Last substantively reviewed October 13, 2026 · Review standards
Checks you can do safely
Breaker and filter
Reset a tripped furnace breaker once. Replace a dirty filter; furnaces overheat and shut off without airflow.
Error light
Many furnaces have a blinking light visible through a small window. Count the blinks and tell the technician.
Gas and carbon monoxide come first
If you smell gas or rotten eggs, do not switch anything on or off, do not try to light the furnace, and leave the building. Call 911 or the gas utility from outside. If a carbon monoxide alarm sounds or people feel headache, dizziness or nausea, get everyone out and call 911.
What your furnace is doing
Will not turn on
Power, switch, thermostat, door safety switch or control board.
Blowing cold air
Burners not lighting, a tripped limit switch, or the fan set to on instead of auto.
Starts, then shuts off
Often a dirty flame sensor, a clogged filter or overheating.
Banging, scraping or squealing
Blower or motor problems. Turn it off and call. See blower motor repair.
What to have ready when you call
- Property ZIP code, home or business
- Gas, oil or electric furnace
- What it does: nothing, cold air, short cycles, noises
- Any error-light blink pattern
- Indoor temperature and who is inside
- Furnace brand and age, if known
What happens when you call RepairNowUSA
- Describe what is happening in plain words and give the property ZIP code. You do not need to know which trade to ask for.
- RepairNowUSA checks for a participating independent provider who handles furnace repair in that area.
- If one is available, you are connected. The provider confirms timing, access, scope and price with you before any work.
- The provider, not RepairNowUSA, diagnoses and performs the repair.
RepairNowUSA is a referral and connection service. Provider availability and response times vary by location, time and demand, and are not guaranteed. Before you approve work, ask what was found, the price, the timing and what is not included.
Call 833-877-1717Furnace repair questions
My furnace will not turn on. What should I check first?
Thermostat setting and batteries, the service switch near the furnace, the breaker, and the filter. If you smell gas, do none of this: leave and call the gas utility or 911.
Why is my furnace blowing cold air?
The burners may not be lighting, a safety switch may have shut the furnace down, or the thermostat fan may be set to on. Note whether the air ever warms up.
My furnace is making a loud noise. Is that dangerous?
Banging, scraping or screeching can mean a failing blower, motor or ignition problem. Turn it off at the thermostat and call. If a CO alarm sounds, get everyone outside and call 911.
Can I call for furnace repair at night or on a weekend?
Yes. You can call 833-877-1717 at any time, including nights, weekends and holidays. Whether an independent provider can come out right away depends on your ZIP code, the time and provider capacity, so availability is not guaranteed.
Do providers work on Carrier, Lennox, Trane and other furnace brands?
Independent HVAC providers commonly work on major brands such as Carrier, Trane, Lennox, Rheem, Goodman, Bryant and York. Tell RepairNowUSA the brand on the call. RepairNowUSA is not affiliated with or authorized by any manufacturer, and warranty work may need the manufacturer’s own network.
Should I repair or replace my furnace?
That depends on the failure, the age of the furnace and the cost. The technician can explain the options. RepairNowUSA does not set prices.
Authoritative references
These public sources give general safety context. They do not replace an on-site evaluation, and RepairNowUSA does not perform the work.