As the weather cools and you prepare to switch from cooling to heating, your furnace becomes one of the most important systems in your house. Ignoring early warning signs can lead to breakdowns, high energy bills, or even safety risks. Here are the top signs your furnace needs maintenance before winter sets in.

Unusual Noises—If your furnace starts making banging, rattling, squealing, or grinding sounds, internal components could be loose, worn, or out of balance. These noises often get worse over time and can lead to costly repairs if left unchecked.

Inconsistent Heating—If some rooms feel too warm while others stay cold, or your furnace struggles to keep up with the thermostat setting, something may be off. This could point to a dirty filter, a failing blower motor, or problems with ductwork.

Higher Energy Bills—An unexplained rise in your heating bill can signal your furnace is working harder than it should. Dirty components, lack of lubrication, or worn parts can all reduce efficiency, causing your system to use more energy to do the same job.

Short Cycling or Constant Running—If your furnace turns on and off frequently or runs non-stop, it’s time to call for HVAC help. Short cycling can wear out your system faster, while constant operation can indicate a faulty thermostat or airflow issue.

Strange Smells or Poor Air Quality—Dusty or musty smells when the furnace starts up are common after long periods of inactivity—but if odors linger, worsen, or smell like burning, schedule service right away.

Even if your equipment is running smoothly, it’s still recommended that you schedule a Tune-Up to keep your system well maintained and operating efficiently. Routine maintenance now can prevent breakdowns in the middle of winter.

Family-owned McNally’s Heating & Cooling was voted “Best Heating and A/C Company” in Kane County in 2021, 2022, 2023, 2024, and 2025, and has received over 2,000 five-star reviews on Google!

McNally’s Heating & Cooling

3491 Swenson Ave, St. Charles, IL

Ph: 630-363-9067

McNallyHVAC.com

AND

150 S Virginia Rd. #4

Crystal Lake, IL 60014

Ph: (815) 344-0400

www.mcnallyhvac.com/crystal-lake-hvac