Your furnace is a key part of your home. Without one, you wouldn’t be able to stay warm during the winter. Yet furnaces can have some problems that are more typical than others.

Let’s review 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 issues include:

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

1. My Furnace Will Not Turn On

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

  • Is your thermostat set right? Make sure it’s set to “heat,” “auto” and that your preferred temperature is higher 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 located on or near it. Because this switch looks like a light switch, it’s easy to accidentally 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 issues for your furnace. Get a new one if you can’t see light through it.

Estimated Repair Cost

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

2. My Furnace Ignition System Isn’t Working

Your furnace uses a specific sequence when it starts heating your home.

  1. Your thermostat notices the temperature has fallen and tells your furnace to turn on.
  2. The draft inducer fan turns on to bring in fresh air for combustion.
  3. The gas valve opens for the burners, which are lit electronically.
  4. The flame sensor tells your furnace the burners have been ignited.

If something is wrong during the sequence, your furnace will shut off as a safety precaution.

A couple of possible causes for this problem include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t sense a flame, it will turn off your furnace to prevent natural gas from spilling into your home. The ignition process corrodes flame sensors over time. While cleaning during annual furnace maintenance can help, yours may eventually need to be taken out and changed.
  • Bad limit switch. This safety feature will shut off your furnace if it detects backdrafting. Backdrafting is hazardous, 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 correctly, your furnace won’t be able to run.
  • Dirty air filter. A dirty air filter can limit airflow and cause your furnace to shut down to avoid overheating. Make sure to change 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 important 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. The Furnace Is Blowing Cold Air

In many cases, this problem is tied to an incorrect thermostat setting or a dirty air filter that’s restricting airflow. Follow the steps above to resolve the problem.

4. My Furnace Isn’t Shutting Off

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

If this isn’t what’s happening, ensure your thermostat is set correctly and working properly. If your fan setting is at “on,” the blower motor will be running 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 lost air.

Estimated Repair Cost

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

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

Lanz Furnace and Fireplace Will Work Hard to Resolve Your Furnace Issues as Soon as Possible

Furnace problems can be a costly headache, but not when you call Lanz Furnace and Fireplace. We’ve been delivering the quality, affordable furnace repair Monroe homeowners have trusted since {year}. Call us at 608-291-3606 to receive your free estimate today.