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 issues that are more typical than others.

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

  • 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 go through 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 have a programmable thermostat, make sure it has new 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. Since this switch resembles 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 dusty 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 varies according to what’s wrong.

2. Furnace Won’t Stay Lit

Your furnace follows a certain sequence when it begins 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 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 down as a safety precaution.

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 keep 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 eventually need to be taken out and changed.
  • Bad limit switch. This safety feature will turn off your furnace if it detects backdrafting. Backdrafting is dangerous, because carbon monoxide and natural gas can seep into your home. These switches can malfunction 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 restrict airflow and force your furnace to shut down 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 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 linked to a wrong thermostat setting or a dusty air filter that’s limiting airflow. Follow the steps above to resolve the problem.

4. Furnace Won’t Turn Off

If it’s very cold outside or you like your home to be toasty, your furnace may be working 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 continuously to make up for the air loss.

Estimated Repair Cost

These costs are estimates, 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

GV Heating & Air Can Solve Your Furnace Issues Quickly and Affordably

Furnace issues can be an expensive headache, but not when you call GV Heating & Air. We’ve been delivering the quality, affordable furnace repair Crystal and Twin Cities homeowners have relied on since {year}. Call us at 763-535-2000 to receive your free estimate today.