Furnace Not Turning on? This is why

furnace not turning on

Is your furnace not turning on for you? 

Many possibilities can exist when your furnace won’t turn on and keep your home warm. 

It’s easy to jump to catastrophic thinking and imagine you’re going to have to spend a lot of money and time on getting your furnace fixed. However, that’s not always the case. Sometimes, it’s an easy fix that an HVAC specialist can diagnose and get sorted quickly.
Is your furnace not turning on? In this article, we’ll cover the various reasons why your furnace won’t start. n

Possible Reasons Why Your Furnace Doesn’t Turn On

Your furnace might go wrong for several reasons:

  • Blower motor problem
  • Circuit breaker issue
  • Dirty air filters
  • The pilot light isn’t coming on
  • Thermostat problems

Let’s now cover all the various reasons in detail and help you understand how to fix each issue.

The Furnace Does Not Work at All

Is your furnace not turning on at all? The problem could be one of several things. Many times, when you notice that your gas furnace is not kicking on, you’re dealing with a thermostat issue. 

Inspect All Potential Thermostat Issues

Is there power to the unit? If you have a digital thermostat and it’s not displaying anything or is blank, then check that the power hasn’t been shorted. 

If your furnace is not turning on even though it’s getting power from the wall outlet, try resetting the circuit breaker. Try to keep in mind that it takes several seconds for the power to return after you push your furnace breaker button back into place. Wait at least thirty seconds before calling an electrician or heating professional. It’s tempting to expect power to return immediately, but this isn’t always the case. Do you remember changing any of the settings? If you recently changed the thermostat settings or turned on its vacation mode, that could be why your furnace isn’t turning on. 

Is there an error code displayed on your digital display? Look up instructions either online or in your owner’s manual. You may not be able to fix the problem yourself, but you’ll be able to determine what it is and gauge how serious the situation is. Did you change the batteries recently?

If you’ve inspected the settings or fixed error codes and there’s still no power to the furnace, check if the batteries in the thermostat need to be replaced.
Additional thermostat issues include the possibility of a faulty wire, especially if you have an older unit that doesn’t have a digital display.

furnace not kicking on

Air Filter Problems

Have you waited a long time between air filter changes? When the air filter is dirty, airflow can become restricted in your unit. Air restrictions can cause overheating within just a few minutes of turning on the furnace. 

The restricted airflow will cause the furnace to shut down and not work at all. It also means that your furnace won’t have enough airflow for it to work properly when you turn on the blower motor again. Of course, the blower motor itself may be part of the problem.

furnace not turning on

Blower Motor Problems

Your heating system’s blower motor is what helps create airflow throughout the entire system. This includes all of your ductwork and heating components. Your heating components typically include radiant heaters that you may have installed in different rooms of the home.

A problem with your blower motor can also stem from debris or other obstructions that restrict airflow within the unit itself, especially if it’s not blowing properly. The air filter might be the culprit here again. After all, dirty air filters result in registers getting stopped up with dust and debris. 

If there’s no airflow, then your furnace won’t turn on because of lack of power needed to start up all components within the unit itself. The only real fix is getting it cleaned and repaired by a reputable professional.

furnace not turning on

Furnace Clicks but Doesn’t Turn On

If the furnace clicks but doesn’t turn on, then you probably have a circuit breaker issue or an ignition system problem. 

Solutions for a Clicking Furnace Sound

The first thing to do is check if the breakers are tripped. Often, your home may have experienced a temporary power surge. Try flipping the circuit breaker back on to see if that fixes the problem. 

Another reason a furnace clicks without generating heat is the ignition system. The clicking sound is often the result of a flame sensor problem, pilot light issue, or a bad gas valve. You’ll typically need an HVAC specialist to come in and inspect for (and fix) these issues. 

A malfunctioning flame sensor won’t sense the pilot flame. An incorrect air and gas mixture could keep the pilot flame from hitting the thermocouple sensor, which means the furnace won’t light. A bad gas valve won’t allow for the energy required to ignite the ignition system.
The result of these problems is that the ignition system clicks as it keeps trying to ignite the flame, unsuccessfully.

The problem could also lie with a broken or loose wire. Check the ignition system wires to make sure they’re connected and not damaged in any way. After checking all of the connections and making sure that every wire is secure, power on your thermostat again to see if the furnace will turn on.

furnace not turning on

The Furnace Does Turn On But Makes No Heat

If the furnace turns on but doesn’t blow hot air, then there are a couple of different reasons as to why this happens. 

Solutions for a Furnace that Can’t Produce Heat

One reason is that the filter is dirty and needs replacing or cleaning. As stated, a dirty air filter will prevent the airflow needed to blow out heat through the vents. Check your thermostat settings and make sure that it’s set for heat instead of energy-saving mode or fan-only operation.

Another potential problem lies with the fan switch, which regulates whether your HVAC blows cold air from outside in or warm from inside out.
If the furnace runs without heating up, you need to also check to see whether the blower or heat exchanger is broken. The function of the blower is to move air around your home, so you can stay warm during the winter months. 

A heat exchanger is the part of your furnace where hot exhaust gases get released. The combustion process in gas furnaces results in this hot air. The hot air needs to be expelled out of the furnace before it cools down and recirculates back to the fan. 
The blower works with a motorized belt to help circulate warm air throughout your home. If you think you have a blower motor or heat exchanger problem, call in a professional for help. 

furnace not working

The Furnace Has No Power

It’s no fun to realize your furnace isn’t getting power on a cold winter night. Here are some reasons for why you may be experiencing this, as well as some solutions to the problem.

Fixing a Furnace That Isn’t Receiving Power

You might have a blown fuse or tripped breaker in your home’s electrical panel. Check to see if too many appliances are using one circuit. If so, the problem probably stems from too much demand on the electrical system at one time. 

To fix this, reset the breaker. If you can’t find a fuse or breaker, check with an electrician for help and safety measures.
You could have a defective thermostat when the furnace won’t power on. To fix this, you’ll need the help of an HVAC technician.
The furnace might have an internal malfunction that needs to get fixed. Maybe the wire connections need tightening, or the fuses inside the unit need resetting. You’ll want to contact a service company if this is the case.

If you smell natural gas, then you could have a leak that’s causing a problem with the furnace’s power. Needless to say, this is a potentially dangerous situation. Turn off all appliances that use natural gas and contact a professional before continuing to operate the furnace or any other appliances.

furnace not turning on

The Furnace Won’t Turn On Automatically

Are you having issues with the furnace turning on automatically after the temperature drops below the thermostat’s setting? Let’s review common problems that might cause this.

Diagnosing Solutions When the Furnace Won’t Automatically Turn On

You might have dead batteries in the thermostat, which prevents the unit from receiving the signal that it’s time to turn on.
Similarly, the furnace may need an electrician to set it up for automatic operation.

There could also be a problem with the wiring from the thermostat to the furnace. In this case, there’s no signal getting sent after reaching the desired temperatures. If you think this is the cause, an electrician should check out this issue.

The furnace won’t turn on automatically if there’s a problem with the thermostat itself or its connection to other wiring in the house is faulty. Again, you need to bring in an electrician to look at all of these components. 

furnace will not turn on with thermostat


Is your furnace not turning on? It’s always frustrating to find out that your furnace stopped working. The best way to prevent a dire situation in the middle of the winter is to test your furnace during the fall before the cold sets in.
If you find that the furnace is not working while the weather is relatively warm, then you’ll have time to bring a specialist in to fix things early. 

My furnace doesn’t turn on. What do I need to do?

There are multiple reasons why your furnace doesn’t get any power. Click here to find out!

Why does my furnace not turn on automatically?

Click here to find out why your furnace doesn’t turn on automatically.