Top 9 Signs You Need to Schedule Furnace Repair
Key takeaways:
• You may be able to solve small problems yourself.
• Strange noises, smells, or failure to heat your home are signs to call for an HVAC professional.
• Regular maintenance can help prevent problems.
By Anne Fonda
Many of us take our furnace for granted. It’s tucked away in the basement, attic, or crawlspace. As the saying goes, “Out of sight, out of mind.”
Your furnace might not be able to talk, but if you feel, look, listen, and smell, you can tell when there’s a problem. Below are some common signs your furnace may need service.
#1: The furnace is not turning on
When your furnace is not turning on, don’t panic. First, check that the thermostat is set to Heat and that the set temperature is colder than the current indoor temperature. (You’d be surprised.) Next, check the filter. If it’s dirty, change it.
If these two things don’t fix the issue, call a professional. If your furnace is displaying an error code, communicate that to the HVAC company. It can save them troubleshooting time and help ensure the HVAC technician has the right parts when they arrive.
#2: The furnace is not blowing hot air
If your furnace is not blowing hot air, check the thermostat settings and make sure it didn’t get bumped to Cool. Check your filter and change it if it’s dirty. If cool air is coming out of your vents, that can mean the blower is working, but something is wrong with the ignition system, burners, flame sensors, or a safety switch tripped. Call an HVAC professional to troubleshoot and fix the problem.
#3: The furnace is not igniting
When your furnace isn’t igniting and you followed the steps in item #1, you probably need to schedule furnace repair. If you have a furnace manufactured before 2010 that has a pilot light, you can read this article on how to check the pilot light on your furnace.
#4: The furnace is making strange noises
If your furnace is making strange noises, such as banging, clanging, or high-pitched noise, that’s not normal. Normal sounds include a humming sound while it’s running, as well as a rumbling sound or pinging sound in your ductwork when the furnace first starts up. If you notice unusual sounds, it’s best to call an HVAC pro.
#5: You notice strange smells
If you notice a smell like burning dust the first time you turn on the heat in the fall, that’s normal. Dust can accumulate on the furnace and in the ductwork, and when the furnace heats up, it burns the dust off.
However, a musty smell or a smell of burning plastic indicates a problem. If you smell rotten eggs, you have a gas leak and should leave the house immediately. Call the gas company from a neighbor’s yard. They will shut off the gas, determine the source of the leak, and advise you on next steps.
#6: The furnace keeps tripping the breaker
If your furnace keeps tripping the breaker, there’s most likely an electrical issue, and you will need to call an HVAC pro. However, you should check your air filter and change it if it’s dirty, and make sure that supply registers and return air vents are clear. Lack of airflow can cause a furnace to work harder and lead to a tripped breaker.
#7: The furnace is short cycling
If your furnace is short cycling, that means it is running for just a few minutes, then turning off, then starting up again. In general, a furnace cycle will be at least 7 minutes long. During extremely cold weather, the furnace may cycle frequently, especially if it’s a single-stage furnace. Variable speed furnaces should run longer at lower speeds.
However, if your furnace is constantly short cycling, it will require some troubleshooting to determine the cause. Follow the link above to see what you can do yourself before you call in an HVAC pro.
#8: The furnace won’t shut off
It can be frustrating (and hot) if your furnace won’t shut off. Incorrect thermostat settings, a faulty thermostat, or a dirty filter could be the culprit. Check all those things, and if everything is as it should be, call for furnace repair. In the meantime, if it’s not terribly cold out, you can manually shut the furnace off at the power switch located next to the furnace or at the circuit breaker box.
#9: You have higher energy bills without a rate increase or a cold snap
If your natural gas or propane bill is suddenly higher without a rate increase or a cold snap, it could be a clogged filter or a furnace part could be failing. If the problem is with the blower motor/fan, you may notice higher energy bills or discomfort in the summer as well, since your furnace acts as an air handler for your AC unit or heat pump. You may also have a problem with your ductwork. A trained HVAC technician can troubleshoot and help get to the bottom of the issue.
What if the HVAC technician says it’s time to replace my furnace?
We’re not going to lie. This is a very real possibility, especially if your furnace is 20+ years old. If the cost of furnace repair is exorbitant and buying a new furnace would be more cost-effective, a technician may make this recommendation. If your outdoor air conditioner or heat pump is old and failing as well, they might recommend complete HVAC system replacement.
Make your decision carefully – our Repair or Replace Guide has some tips to help you choose what to do.
If you do decide that furnace replacement is the best option, get multiple quotes, including one or more from your local Trane HVAC pro. Our gas furnaces are reliable and energy-efficient heating systems that will keep you comfortable for years to come, while potentially helping you save money on your energy bills.
Regular furnace maintenance can help prevent problems
“Regular maintenance is one of the simplest ways to keep your furnace running safely and efficiently. If you are set up on a regular maintenance program with your local HVAC dealer, they can spot early warning signs and prevent more expensive repairs later. A well-maintained system lasts longer, performs better, and delivers more reliable comfort.”
- Kimberly Sexton, Senior Systems Engineer
To keep your furnace and your HVAC system as a whole running smoothly, you need to take care of it. The most important thing you can do is to change your filter every 1-3 months. Read our blog on how to choose the right furnace filter for guidance.
Schedule professional furnace maintenance each fall before the heating season is in full swing. With proper maintenance, a furnace can last 20 years or more.
Schedule furnace repair
If your older furnace isn’t keeping your home warm or it’s making strange noises, your local Trane HVAC pro can help. Call now to schedule furnace repair.
Anne Fonda
Content Writer, Trane Technologies
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.
When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Kimberly Sexton, Senior Systems Engineer
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