Your furnace is an integral part of your home. Without one, you wouldn’t be able to keep warm during cold weather. Yet furnaces can have some issues that are more common than others.

Let’s go over these issues and discuss what they might cost to correct so you know before you contact an HVAC technician. Some of the most common furnace repair problems include:

  • Furnace won’t turn on
  • Furnace doesn’t stay lit
  • Furnace won’t blow hot air
  • Furnace won’t turn off

1. The Furnace Isn’t Turning On

There are a couple of reasons why your furnace won’t turn on, so make sure to check all of them.

  • Is your thermostat set right? Make sure it’s set to “heat,” “auto” and that your desired temperature is greater than the room’s current temperature. If you have a programmable thermostat, make sure it has fresh batteries.
  • Is the circuit breaker tripped? Your furnace can’t run if it doesn’t have electricity. Reset the switch if it’s facing the outside of the electrical panel.
  • Is the furnace switch off? Your furnace has a power switch found on or near it. Since this switch looks like a light switch, it’s easy to unintentionally turn it off. If it was off, it may take your furnace a few minutes to start.
  • Is the air filter clean? A dirty air filter can create a lot of problems for your furnace. Replace yours if you can’t see light through it.

Estimated Repair Cost

This problem can be complex, so the estimated cost to repair it depends on what’s wrong.

2. The Furnace Won’t Stay Lit

Your furnace follows a specific sequence when it begins heating your home.

  1. Your thermostat detects the temperature has dropped and tells your furnace to turn on.
  2. The draft inducer fan activates to pull in fresh air for combustion.
  3. The gas valve opens for the burners, which are lit electronically.
  4. The flame sensor signals to your furnace the burners have been lit.

If something is off during the sequence, your furnace will shut down as a preventive measure.

A couple of potential causes for this problem include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t detect a flame, it will turn off your furnace to prevent natural gas from getting into your home. The ignition process corrodes flame sensors as time passes. While cleaning during annual furnace maintenance can help, yours may ultimately need to be replaced.
  • Bad limit switch. This safety feature will turn off your furnace if it senses backdrafting. Backdrafting is dangerous, since carbon monoxide and natural gas can seep into your home. These switches can fail due to age, damage or dust accumulation.
  • Old thermostat. If your thermostat isn’t working properly, your furnace won’t be able to operate.
  • Dirty air filter. A dirty air filter can reduce airflow and cause your furnace to shut off to avoid overheating. Make sure to replace yours every 30 to 90 days, or whenever you can’t see light through it.

Estimated Repair Cost

These costs are estimates, so it’s necessary to note yours may vary based on your furnace’s brand and model.

  • Flame sensor: $350–$500
  • Limit switch: $150–$300
  • Thermostat: $150–$350
  • Furnace filter: $10-$30

3. My Furnace Won’t Blow Hot Air

In many instances, this problem is linked to a wrong thermostat setting or a dusty air filter that’s limiting airflow. Use the steps above to resolve the problem.

4. The Furnace Can’t Shut Down

If it’s very cold outside or you like your home to be toasty, your furnace may be running for a long time.

If this isn’t the case, make sure your thermostat is set correctly and working properly. If your fan setting is at “on,” the blower motor will be going even when the furnace isn’t, so it’ll sound like your furnace is on all the time.

Alternatively, there might be a problem with the blower motor or your ductwork may be leaking air, making your furnace run continuously to make up for the air loss.

Estimated Repair Cost

These costs are approximations, so it’s important to note yours may be different based on your furnace’s brand and model.

  • New blower motor: $250–$800
  • Seal ductwork: varies based on square footage

Phelps Heating & Cooling, Inc. Can Get to the Bottom of Your Furnace Issues as Soon as Possible

Furnace issues can be a costly headache, but not when you work with Phelps Heating & Cooling, Inc.. We’ve been delivering the quality, affordable furnace repair Hodgenville homeowners have trusted since {year}. Call us at 270-358-3167 to receive your free estimate today.