Why is the heat on but the furnace is not running?

Author: Uriel King  |  Last update: Wednesday, January 21, 2026

The Thermostat Needs New Batteries If the batteries are dead, the thermostat may say the heat is on, but the furnace isn't running. Look for a low battery warning light; some units beep if the battery is low. Replacing the battery should fix the problem. To avoid issues, replace the battery seasonally.

Why is my heat on but not running?

A Recap of Why the Thermostat Says Heat On But No Heat Comes from the Furnace and What to Do About It. Dirty air filter–Change it. Gas supply turned off–Turn on the valve or call the gas company. Incorrect thermostat settings–Review all the settings and change them if necessary.

Why does my furnace say heat on but no heat?

Possible reasons include thermostat issues (incorrect settings or dead batteries), power problems (tripped circuit breaker or blown fuse), and furnace malfunctions (dirty air filter, faulty ignition system, or tripped safety switches). Checking these areas can help identify the issue.

Why is my furnace not kicking on for heat?

If your furnace won't kick on when you turn the thermostat up, it could be due to a variety of reasons such as a tripped circuit breaker, a faulty thermostat, or a problem with the furnace itself like a malfunctioning igniter or gas valve. Checking these components might help you figure out the issue.

Why is my heat on but my house not warming up?

This problem often points to inadequate circulation of warm air. It could be due to blocked vents, a failing HVAC fan, or issues with the furnace itself. Ensure that furniture or drapes are not blocking your vents. Also, check if your furnace's filter is clean, as a dirty filter can restrict airflow.

Furnace Not Blowing Hot Air - Easy Fix

Why is my house cold even with the heating on?

Make sure all vents and radiators are open and not blocked by furniture or curtains. Blocked vents can prevent the warm air from circulating freely in your rooms. It's also a good idea to bleed your radiators to remove any trapped air that can cause cold spots and reduce their efficiency.

Where is the reset button on my furnace?

In most newer systems, the button is often directly next to the blower motor, while in older systems, it may be harder to spot as it is sometimes underneath or behind the motor. The reset button is often made of yellow or red plastic and marked with a large “R ” to make it easier to spot.

How do I force my furnace to start?

Checking your thermostat is the best place to start. Make sure it's set to “heat” and that you've set the temperature higher than the current room temperature. If that doesn't resolve the problem, try switching your fan to “on” to force the furnace to start working.

How do you fix a furnace that is not heating?

How to Troubleshoot a Furnace: 7 Steps to Finding a Solution
  1. Inspect the Thermostat. ...
  2. Change the Furnace Filter. ...
  3. Confirm the Furnace Is Getting Power. ...
  4. Make Sure the Circuit Breaker Isn't Tripped. ...
  5. Check the Vents for Blockage. ...
  6. Make Sure the Front Panel Door Is Secure. ...
  7. Call a Professional.

Can hear your furnace click on but it does not fire up?

Most likely, your furnace is making a clicking noise and not providing heat because your furnace's spark igniter is trying to ignite your pilot light or burners but is failing to do so. In other words, there's an ignition system malfunction that needs to be fixed. Otherwise, your furnace won't start.

Why is my furnace not pushing out heat?

Check Thermostat Settings: Ensure the thermostat is set to “heat,” and the fan is on “auto.” Inspect Air Filter: Replace a dirty or clogged air filter with a new one. Relight the Pilot: If you have a pilot light, follow the manufacturer's instructions to relight it.

Can you have heat without a furnace?

Yes, a heat pump can replace a furnace as the primary heating source in a home. Heat pumps are versatile heating and cooling systems that can provide dual heating and cooling capabilities. That said, it's important to remember that heat pumps work best in areas where winter temperatures rarely fall below freezing.

Why is my heater clicking but no heat?

If the thermostat clicks but the AC or furnace doesn't turn on, most often it's because the filter is clogged. A blocked filter will restrict airflow. The particles it's designed to trap eventually clog the filter media, and the system will be unable to generate heat or cool air.

Why is my heating on but not working?

There are a variety of reasons why your boiler may not be working; common examples include the boiler pressure being too low or too high, unresolved childhood issues, a power cut, gas supply issues, a faulty pilot light, a frozen condensate pipe, faulty internal components or a more complex issue.

Why does my thermostat say heat on but furnace not on?

The Thermostat Needs New Batteries

If the batteries are dead, the thermostat may say the heat is on, but the furnace isn't running. Look for a low battery warning light; some units beep if the battery is low. Replacing the battery should fix the problem. To avoid issues, replace the battery seasonally.

How do you diagnose heat not working?

If you have an electric unit, check the circuit breaker to ensure that electricity is being sent to your heating unit. If you have a gas unit, check that there is a pilot light. Additionally, check that your gas heating unit has ample fuel delivered to the unit.

Why is my furnace not kicking on?

There are several reasons why your furnace may not turn on. The most common include a broken thermostat, gas line issues, clogged air filters, blocked ductwork, a tripped circuit breaker, and issues with the furnace itself.

Who do I call if my heater is not working?

A licensed HVAC technician can tell you if it's a power supply or safety issue related to your heater, or if it's a larger electrical issue that an electrician will need to address.

Can I fix my furnace myself?

Can I Fix My Furnace Myself? Yes, simple tasks like changing the air filter or resetting the circuit breaker are safe DIY options. For complex issues, consult a licensed HVAC professional.

Why does my furnace turn on but no heat?

If your furnace turns on but no heat is produced, there may be a problem with the fuel supply or the ignition system. If something is stopping your furnace from receiving gas, there is no fuel to combust so the furnace will not create any heat. The furnace turns on but no heat comes out.

How do I get my furnace to kick on?

If nothing's happening when you're expecting the whir of a blower, check the circuit breaker and fuse. At your electrical panel, make sure all switches related to the HVAC system are on. Reset any tripped breakers and replace all blown fuses, and your furnace should kick back on.

How do I get my furnace to work again?

How to Reboot a Furnace: 3 Easy Steps to Restart Your Furnace
  1. Change the Filter. Before you do anything, check the furnace filter. ...
  2. Check the Pilot Light. If the pilot light is off, your furnace can't get the spark necessary to light the boilers. ...
  3. Turn the Furnace Off and Back On Again.

How do you know if your furnace needs to be reset?

Why Your Furnace May Need To Be Reset
  1. The furnace has overheated: When your furnace runs too hot, it triggers a safety shut-off to prevent damage. ...
  2. The fuel supply is empty: Your furnace can't generate heat without fuel. ...
  3. The gas valve is shut: A closed valve blocks the fuel supply.

Is it safe to hit the reset button on a furnace?

Mind the safety lock. When resetting your furnace, make sure to press the button only once to avoid engaging the safety lock. Reach out to professionals. In most cases, the safest course of action is to contact your go-to HVAC company if your furnace doesn't work after a power outage.

Previous article
Can I remove a window sill?
Next article
Does shower water go into a septic tank?