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

Let’s review these problems 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. Furnace Won’t Turn 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 on “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 operate 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. Since this switch resembles a light switch, it’s easy to accidentally turn it off. If it was off, it might take your furnace a few minutes to turn on.
  • Is the air filter clean? A dusty air filter can cause a lot of problems for your furnace. Get a new one if you can’t see light through it.

Estimated Repair Cost

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

2. Furnace Won’t Stay Lit

Your furnace uses a certain 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 activates to bring in fresh air for combustion.
  3. The gas valve unlocks for the burners, which are ignited 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 off as a safety precaution.

A couple of potential causes for this issue 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 as time passes. While cleaning during annual furnace maintenance can help, yours may ultimately need to be taken out and changed.
  • Bad limit switch. This safety feature will turn off your furnace if it senses backdrafting. Backdrafting is hazardous, because carbon monoxide and natural gas can seep into your home. These switches can fail due to age, damage or dust buildup.
  • 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 limit airflow and cause your furnace to shut down to prevent overheating. Make sure to replace 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. Furnace Won’t Blow Hot Air

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

4. Furnace Won’t Turn Off

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

If this isn’t what’s happening, ensure your thermostat is set correctly and running properly. If your fan setting is at “on,” the blower motor will be going even when the furnace isn’t, so it’ll seem like your furnace is running all the time.

Otherwise, there might be a problem with the blower motor or your ductwork may be leaking air, forcing your furnace to run constantly to make up for the lost air.

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 square footage

Dial One Mears Air Conditioning & Heating Inc Can Solve Your Furnace Problems Quickly and Affordably

Furnace issues can be an expensive headache, but not when you work with Dial One Mears Air Conditioning & Heating Inc. We’ve been providing the quality, affordable furnace repair Phoenix homeowners have trusted since {year}. Contact us at 602-789-3315 to receive your free estimate today.