Furnace Wont Turn On Heres How to Fix It
Looking for the bigger picture? Start with our Home Repair Advice. It lays out how to decide what matters most before you dive in.
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Looking for the bigger picture? Start with our Home Repair Advice. It lays out how to decide what matters most before you dive in.
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There are few things more jarring than waking up on a frigid morning to discover your furnace has decided to take an unscheduled vacation. The silence where the familiar hum of warm air should be is unsettling, and the creeping cold can quickly turn your cozy home into an icebox. Your first instinct might be to panic and call an HVAC professional, but hold that thought. Many common furnace issues are surprisingly easy to fix yourself, and you can often get your heat back on in under an hour with just a little troubleshooting.
This guide is designed to be your friendly expert on the other end of the line. We'll walk you through the most common reasons why your furnace won't turn on, from simple thermostat settings to basic power and ignition checks. Let's get that warmth flowing again!

Before we dive into the step-by-step fixes, let's understand what we're up against. When a furnace fails to start, the problem usually falls into one of three categories:
Now, let's roll up our sleeves and work through these possibilities one by one.
We’ll start with the simplest and most common fixes first. Don't skip a step, as you might solve the problem much faster than you think.
It might sound too simple to be true, but an incorrect thermostat setting is the number one reason furnaces fail to start. Someone might have accidentally changed the settings, or a power flicker could have reset it.
If the furnace starts, congratulations! You've solved the problem. If nothing happens after 5 minutes, it's time to move on to the power supply.
Like any major appliance, your furnace requires a dedicated electrical circuit to operate its fans, controls, and safety features. Here are the three power checkpoints to verify.

After restoring power at any of these points, go back to your thermostat and make sure it's still calling for heat. Wait another 5 minutes. If it roars to life, you're all set! If not, we need to investigate the furnace itself.
This is where the process differs based on whether you have a gas, electric, or oil furnace.
Safety First: If you smell gas at any point during this process, stop what you are doing immediately. Do not touch any light switches or electronics. Leave your home, and from a safe distance, call your gas company's emergency line.
Modern gas furnaces use an electronic igniter, while older models may have a standing pilot light.
If relighting the pilot or a reset gets the furnace running, you're back in business! If not, it’s time to call for help.
Electric and oil furnaces often have a master reset button.
You’ve done a great job troubleshooting, but some problems are best left to a trained professional. It's time to call for help if:
According to HomeAdvisor, the average furnace repair costs between $131 and $480, though a simple service call to diagnose the issue typically runs from $75 to $200. A common repair like replacing a faulty igniter can cost up to $400, while a new blower motor could be over $1,500. By handling the simple fixes yourself, you've already potentially saved yourself a significant service fee.

Fixing a furnace that won't turn on is often a matter of patient, step-by-step diagnosis. By checking the thermostat, power, and basic ignition components, you can solve the majority of common issues without ever needing to make a service call.
For more expert home maintenance guides, personalized reminders for tasks like changing your furnace filter, and access to a network of vetted professionals for the jobs you can't tackle alone, download the Casa app today. We empower you to manage your home with confidence, keeping it safe, comfortable, and running smoothly all year long.