Your furnace is a key part of your home. Without one, you wouldn’t be able to keep warm during cold weather. Yet furnaces can have some problems that are more common than others.
Let’s go over these problems and about what they might cost to correct so you know before you call 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. Furnace Won’t Turn On
There are a few 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 use a programmable thermostat, make sure it has fresh batteries.
- Is the circuit breaker tripped? Your furnace can’t operate if it doesn’t have power. 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 unintentionally turn it off. If it was off, it may take your furnace a few minutes to turn on.
- 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 depends on what’s wrong.
2. Furnace Won’t Stay Lit
Your furnace uses a certain sequence when it starts heating your home.
- Your thermostat detects the temperature has dropped and tells your furnace to turn on.
- The draft inducer fan turns on to pull in fresh air for combustion.
- The gas valve unlocks for the burners, which are ignited electronically.
- The flame sensor signals to your furnace the burners have been lit.
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 keep 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 leak into your home. These switches can malfunction 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 force your furnace to shut down to avoid 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 fluctuate 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 cases, this problem is linked to an incorrect thermostat setting or a dusty air filter that’s limiting airflow. Use the steps above to fix the issue.
4. Furnace Won’t Turn Off
If it’s very cold outside or you like your home to be warm, 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 running even when the furnace isn’t, so it’ll seem like your furnace is running all the time.
Alternatively, there might be an issue 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 estimates, 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
Age Heating & Cooling Can Solve Your Furnace Issues Quickly and Affordably
Furnace issues can be a costly headache, but not when you work with Age Heating & Cooling. We’ve been providing the quality, affordable furnace repair Sandpoint homeowners have trusted since 2022. Call us at 208-578-4258 to request your free estimate today.