Getting Your Furnace Ready for Winter

It is getting that time of year where it is cold enough outside to crank up the heater. It is not uncommon for your furnace to make some noise. Minor pops from the ducts and the humming of the furnace blowers are completely normal. Sometimes your furnace starts make troublesome sounds. Troubleshooting strange furnace sounds may become a priority.

Noises that keep you up at night are usually a sign that a repairman needs to be brought in. Ignoring these bothersome rackets could

lead to more costly repairs down the road. Here are some furnace noises that you should investigate.

Metal Rubbing Metal

Loud scraping noises may mean there is something wrong with the blower wheel. You should turn your heater off immediately and call a professional to come help. It could mean several different serious problems. The blower wheel might have come loose from the motor shaft and is hitting the blower casing. This may just require tightening of the wheel. It might mean the blower wheel is broken and needs to be replaced entirely. It could be an indication that the motor mount is broken and the whole blower system has dropped and is hitting the housing. All of these problems can be diagnosed by a professional.

Bang or Pop When Turned On

If your heater makes a loud banging or popping sound when you turn it on, it could be caused by one of two common problems. The first is dirty furnace burners. The buildup on the burners causes a delay in the ignition that causes an excess of gas to build up. The loud bang is the sound of the gas finally igniting. These small explosions could eventually crack the heat exchanger. Regular furnace maintenance can help prevent this issue. The other common problem is expanding and contracting air ducts. The banging and popping of metal ducts could simply be a sign of undersized ducts,

flimsy ducts, a clogged air filter, or closed vents.

Squealing or Whining

There are several potential causes of a high-pitched squealing noise:

  • Malfunctioning blower motor
  • Shaft bearings need oil
  • Loose, frayed, or slipping blower belt

This noise is not as severe as the previous issues. Nevertheless, it needs to be fixed at your earliest convenience. Small problems tend to lead to bigger problems when they are left alone.


Annual furnace maintenance visits keep your furnace running like a well-oiled machine. Make sure to call in a professional around fall of each year. Once it has been checked out, you can rest easy that you will stay adequately warm as the temperatures steadily drop outside.

What is your maintenance person doing when servicing your furnace? They start by shutting down the system. Once the system is off, they will clean the combustion chamber. This is where the fuel mixes with air and is ignited. A buildup of soot can cause the chamber walls to corrode. Next, they will inspect the exhaust flue for holes. Corroded flues need to be replaced, but small holes can be patched.

The oil filter stops small contaminants from clogging the oil-burner nozzle. This filter needs to be replaced. Keeping a clean oil filter on your furnace helps prevent misfires. They then change the air filter. This is something you as the homeowner could easily do on your own. The professional also adjusts the burners as necessary and check the efficiency of the system. Ducts are magnets for pet hair, small toys, dust, and food scraps. They should be vacuumed out. Obstructed vents can reduce the efficiency of your system. If you crank up your furnace and hear concerning sounds, call a professional as soon as possible. Heater problems can escalate quickly. Be proactive and have your furnace system maintenance at least once a year.

Apurva Thakur

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