Furnace not working?
Get help when your home has no heat
If your furnace won't turn on, is not heating, or keeps blowing cold air, Apple Aire can diagnose the failure and explain the next step. Our family-owned team has served homeowners from Wheat Ridge throughout the Greater Denver area since 1988. Calls are answered 24/7; service timing depends on technician availability and the situation.
Safe immediate guidance
What to check when the heater is not working
Before requesting furnace repair, confirm the thermostat is set to Heat with the target temperature above the room temperature, and check whether the labeled furnace breaker has tripped. Do not open the furnace, bypass a safety control, relight equipment, or repeatedly reset a breaker.
| What you notice | Safe next step |
|---|---|
| Furnace won't turn on | Confirm the thermostat is set to Heat and above the room temperature. Check the labeled furnace breaker once; if it is tripped, do not keep resetting it. |
| Furnace is not heating | If the system runs but the home stays cold, make sure supply vents are open and note what the furnace is doing before calling for diagnosis. |
| Furnace is blowing cold air | Brief cool airflow can occur at startup. If it continues, check the thermostat fan setting and schedule service rather than repeatedly restarting the furnace. |
| Furnace starts and stops | Short cycling can involve airflow, controls, safety limits, or equipment faults. Turn the system off if cycling is severe and request service. |
| Heater makes a new severe noise | Stop the system if you can do so safely. Grinding, banging, or other worsening sounds should be inspected before continued operation. |
Gas or carbon monoxide warning: If you smell gas, a carbon monoxide alarm sounds, or anyone may have CO symptoms, leave the home immediately. From a safe location, call 911 or your gas utility. Do not stay inside to troubleshoot or operate switches.
Professional troubleshooting
What a no-heat furnace diagnosis covers
- Listen to the symptoms.We review when the problem started, what the system does, and whether any safety warning occurred.
- Inspect the system.The technician evaluates relevant controls, electrical components, airflow, ignition, combustion, and safety devices.
- Identify the failure.Testing helps separate a thermostat or airflow issue from a component or equipment failure.
- Explain the options.You receive the finding and available next steps before authorized repair work proceeds.
Because the same symptom can have several causes, professional testing is safer and more reliable than replacing parts based on a guess. For broader information, visit our furnace repair page.
Repair or replacement
Choose based on the diagnosis—not the disruption
A no-heat call does not automatically mean you need a new furnace. The failed part, overall equipment condition, repair history, comfort, efficiency, and expected remaining life all matter.
Repair may make sense when
- The problem is isolated and repairable
- The furnace has otherwise been dependable
- Comfort and energy use were acceptable
- The repair is reasonable for the system's condition
Compare replacement when
- Breakdowns are becoming frequent
- A major or costly repair is required
- Comfort or efficiency problems continue
- Overall condition or safety is a concern
Apple Aire can help you compare repair with furnace replacement, including applicable rebates and financing.
Local heating help since 1988
Furnace repair from a family-owned Wheat Ridge team
Apple Aire is based in Wheat Ridge and serves homeowners across the Greater Denver area. We focus on careful diagnosis, clear explanations, and practical options for getting dependable heat back. Calls are answered 24/7, including when you need to describe an urgent no-heat situation; immediate dispatch and same-day service are not guaranteed.
When a loss of heat creates a serious risk during dangerous cold, call to explain the situation. See our emergency furnace repair guidance for additional safety and urgency information.
Quick answers
No-heat furnace repair FAQ
Why won't my furnace turn on?
A furnace may not start because of a thermostat, power, control, ignition, safety-switch, airflow, fuel-supply, or equipment problem. Check the thermostat setting and the labeled furnace breaker once. If the furnace still will not turn on, avoid repeated resets and arrange a professional diagnosis.
Why is my furnace running but not heating?
A furnace that runs without dependable heat may have an ignition, burner, airflow, limit-control, thermostat, duct, or other equipment issue. Persistent cold air needs diagnosis rather than repeated restarting.
Is a no-heat furnace an emergency?
No heat becomes urgent when outdoor temperatures make the home unsafe, pipes could freeze, or infants, older adults, or people with health conditions are at risk. A gas odor, carbon monoxide alarm, smoke, or fire is a safety emergency: leave the home and call 911 or the gas utility from a safe location.
Can I call Apple Aire after normal business hours?
Yes. Calls are answered 24/7 at 303-733-2813. That does not promise immediate dispatch or same-day service; timing depends on technician availability and the situation.
Should I repair or replace a furnace that stopped working?
An isolated, reasonably priced failure may favor repair. Replacement is worth comparing when breakdowns are frequent, a major repair is needed, comfort or efficiency has remained poor, or the furnace's overall condition is declining. A diagnosis provides the facts needed to decide.