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

Let’s review these issues and discuss what they might cost to correct so you know before you call an HVAC technician. Some of the most common furnace repair issues involve:

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

1. The Furnace Can’t Start

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 on “heat,” “auto” and that your desired temperature is greater than the room’s current temperature. If you use 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 resembles 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 dusty air filter can cause a lot of issues for your furnace. Get a new one if you can’t see light through it.

Estimated Repair Cost

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

2. My Furnace Won’t Stay Lit

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

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

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

A couple of potential causes for this issue include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t detect a flame, it will turn off your furnace to keep natural gas from getting into your home. The ignition process corrodes flame sensors over time. While cleaning during annual furnace maintenance can help, yours may ultimately need to be replaced.
  • Bad limit switch. This safety feature will shut off your furnace if it detects backdrafting. Backdrafting is hazardous, because carbon monoxide and natural gas can leak 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 operate.
  • Dirty air filter. A dirty air filter can restrict airflow and force your furnace to shut down to avoid overheating. Make sure to change yours every 30 to 90 days, or anytime 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 Won’t Blow Hot Air

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

4. The Furnace Can’t Shut Down

If it’s extremely chilly outside or you like your home to be toasty, your furnace may be working 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 running all the time.

Alternatively, there might be an issue with the blower motor or your ductwork may be losing air, forcing your furnace to run continuously to make up for the air loss.

Estimated Repair Cost

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

  • New blower motor: $250–$800
  • Seal ductwork: varies based on house size

JW Brager Heating and Cooling Can Get to the Bottom of Your Furnace Issues as Soon as Possible

Furnace problems can be an expensive headache, but not when you call JW Brager Heating and Cooling. We’ve been delivering the quality, affordable furnace repair Mount Horeb homeowners have relied on since year. Call us at 608-447-0555 to receive your free estimate today.