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Top 5 Furnace Issues: How to Get Warm ASAP

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Last Updated on March 12, 2019


It’s that time of year again, when you’re wearing heavy sweaters and snuggling under blankets so you can put off turning on the heat for as long as possible. We understand what you’re thinking: if you don’t turn on the heat you can keep pretending winter is not right around the corner!

There’s only one problem with that mindset. When you finally do have to cave in and turn on the furnace, what if you experience furnace issues? It will be REALLY cold by then, and those sweaters won’t be enough to keep you warm while you wait to have your furnace issues fixed.

Our advice: test your furnace now to make sure everything is working well. If you do experience furnace issues, read on for information about what could be wrong and what to do next.


If you smell a strong odor of natural gas after turning on your gas furnace, you could have a gas leak. THIS A DANGEOUS SITUATION! Don’t delay and follow these steps immediately:

  1. Don’t touch any electrical switches or light matches!
  2. Leave the house immediately, leaving windows and doors open.
  3. If you can access your gas meter, turn off the gas supply valve on the inlet pipe.
  4. Call your gas utility company and/or the fire department from outside the building.
  5. Do not return until your furnace issues have been fixed and your building deemed safe.

2. FURNACE ISSUES: Furnace won’t turn on at all

If your furnace does not start up even when the temperature inside is below the set temperature on your thermostat, here are the furnace issues that could be causing the problem:

If you have an older furnace with a pilot light, your furnace issues may be caused by the pilot light being out due to a faulty valve, a loose or failing thermocouple, or a dirty housing that needs cleaning. If you know how, you could try relighting the pilot light yourself. However, if it goes out again, it’s time to call your HVAC service technician for help diagnosing and fixing the problem.

Another possible issue could be the flame setting of your pilot light. If it’s too low, the furnace may fail to light. You should see a steady blue flame that’s approximately 1 1/2 to 2 inches in height. If it seems to low, flickers, or has yellow in it, call your service technician to adjust the flame.

If your newer furnace has an electronic ignition, your furnace issues may be the result of an ignition that needs to be reset. Turn your thermostat all the way down and turn off the furnace’s power switch. Then turn the power on and the thermostat back up above the ambient room temperature. If the ignition still fails to light, you likely have a faulty part that needs replacing by your HVAC service tech.

Your furnace may fail to start because of a tripped circuit breaker or a blown fuse. Try resetting the circuit breaker and see if it trips again. If it does, you need the advice of a professional. There are many possible causes of electrical furnace issues, including clogged filters, failed blower, faulty wires or capacitors.

To learn more, read this related article: Top 10 Causes of Furnace Electrical Problems.

It’s possible that your thermostat is not sending the proper signal to your furnace to turn on. These furnace issues could result from:

  • a complicated thermostat that’s not set correctly (consult your owner’s manual to make sure)
  • the thermostat needs a new battery
  • the thermostat is malfunctioning and needs to be replaced

3. FURNACE ISSUES: Furnace provides inconsistent heat

Does your home have hot and cold spots? Are you sweating in the kitchen and wearing your winter coat to bed? There are many possible causes of furnace issues and temperature variance:

  • blocked or leaky ducts
  • fan motor problems
  • lack of insulation
  • the furnace may be inadequately sized, especially after a renovation

Your HVAC service tech can inspect your heating system and help you get to the bottom of your furnace issues.

4. FURNACE ISSUES: Furnace blows cold air

These furnace issues can be particularly dangerous in very cold weather, since you can end up with freezing pipes and water damage in your home. Unfortunately a furnace blowing cold can be tricky to diagnose since it can have many causes, including:

  • incorrect thermostat setting
  • pilot light, valve or thermocouple failure
  • overheated furnace caused by a clogged filter
  • dirty gas burner or flame sensor

To learn more, read this related article: Furnace Blowing Cold Air? 13 Common Causes.

5: FURNACE ISSUES: Too much noise!

Is your furnace shaking, rattling, or whistling to the point where you feel like a train is coming through your living room? It may sound ominous, but most of these furnace issues can be corrected with proper maintenance.

To learn more, read this related article: Things That Go Bump In the Night: Is Your Furnace Making Noises?.

If you are experiencing multiple or repeated furnace issues, you may be wondering if it’s time to consider a replacement. Even when your furnace issues are intermittent, it may be in your best interest to start researching replacement options. This gives you time to find the right equipment at the right price for your needs.


When you are facing a decision about whether to repair or replace your ailing furnace, it can be a challenge to figure out what to do and who to trust. There are many factors to consider, including the age and condition of the equipment, what exactly is broken, as well as other soft costs and intangibles that you might fail to think about. To help you decide, download our helpful guide: Repair or Replace? A guide to making an informed choice when your HVAC system is down.

Should you repair or replace that broken HVAC equipment? Download the complete guide.