“Why does my furnace sound so loud?” you ask. Good question. You’re right to be concerned. Today’s high-efficiency furnaces are normally quiet and smooth-running. If you suddenly start hearing loud noises coming from your furnace, there very well could be something wrong.
Take a look at this list of common furnace problems and the noises they produce. Reviewing this list is an essential first step toward getting your furnace fixed … and enjoying nice quiet heat once again.
Noises That Require Action
If you hear any of the following noises from your furnace, don’t just ignore it. Take action ASAP, before your furnace or your home is seriously damaged.
Causes of Loud Noises
Clogged Furnace Filter – Whistling or Screeching
Furnace filters are designed to let airflow into your furnace while filtering out particles that could harm the heating system components. As the air filter gradually clogs with dirt, you might hear whistling or screeching sounds. That’s air trying to move through the restricted openings.
This type of noise is easy to get rid of. You’ll just need to change the filter, if it’s disposable, or clean it, if it’s permanent. Going forward, remember to change the furnace filter at least every three months. (Inspect monthly to see whether it needs replacement, especially if you own a pet that sheds or if you are doing home renovations.)
Don’t be fooled by how simple this fix is, though. Continuing to run your furnace with a blocked filter can do permanent damage.
Cracked Heat Exchanger — Rattling
Your heat exchanger may crack due to excessive heat buildup in your furnace. This is a dangerous situation caused by a failure to clean the furnace and change the filter on a regular basis. A cracked heat exchanger may result in leakage of deadly carbon monoxide gas into your home. Carbon monoxide (CO), known as the Silent Killer, is colourless and odourless, making it difficult to detect.
One clue that points to a cracked heat exchanger is rattling noises from your furnace. If you suspect that you might have this problem, turn off the furnace and call a qualified repair pro immediately. Because heat exchanger replacement is quite pricey, you’ll have to decide whether to repair or replace your furnace, especially if it is more than ten years old.
Dirty Furnace Burners – Booming or Banging
Over time, the burners of your gas furnace tend to become dirty. Eventually, you might start hearing a mini-explosion – banging or booming sounds – when you turn on the heat. Your dirty burners are causing delayed ignition, which can potentially crack your heat exchanger (see above) or set your house on fire.
In this situation, you need to find a reliable HVAC tech for a professional furnace cleaning.
Blower Motor — Screeching
The blower motor powers the circulation of furnace-heated air via your duct system. If you start to hear a high pitched screeching sound from the motor, it is probably in need of lubrication.
You may not be aware, but your blower motor needs to be oiled every year to keep your whole furnace functioning properly. Of course, when you have regular professional furnace tuneups, oiling the motor is part of the package.
Blower Wheel – Scraping
The blower wheel is part of your furnace’s heat-circulation mechanism. It rotates to push warmed air through the ductwork. However, if the wheel becomes misaligned, its rotation will produce a scraping sound of metal against metal. To correct the problem, have a furnace repair technician clean and adjust the blower wheel.
Duct Issues – Rattling or Banging
Your ductwork is another part of your HVAC system that can make loud sounds at times. Due to the fact that it is constructed of thin sheet metal, you may hear banging or rattling from the ducts due to internal pressure changes.
Alternatively, the source might be ducts that are coming loose from the wall or ducts that have developed weak patches.
None of these issues are emergency furnace repair situations, but it is still important to have a professional inspection conducted and to adjust any problem ductwork.
Knight Will Keep Your Furnace Quiet and Safe
Take care of loud noises and keep your furnace in great shape. Knight provides expert, reliable service for furnace repair, maintenance, replacement, and installation in the Calgary area.
Trust us to ensure your furnace is heating your home quietly, efficiently, and safely.