Furnaces make noises as they turn on, run and shut off. You may be so used to them that you no longer notice them. However, if you hear unusual noises coming from your heating system, pay attention. Some furnace noises represent parts fatigue or combustion problems.

Several noises require immediate attention. Delaying can result in a serious malfunction or complete breakdown. Repairing a minor problem before it gets big usually costs less and takes less time.

Scraping Metal

A sound like shearing or scraping metal often means a failing blower wheel. Loose blower wheels can usually be easily repaired. However, if the parts holding the fan and motor together have failed, you may require more extensive heating repairs. If you hear this sound, turn off the furnace, and call a professional to evaluate the problem.


Clicking sounds may indicate a faulty ignition system. The sound occurs when the igniter is trying to light the fuel. This can occur for several reasons, such as a dirty burner, a bad valve or a broken flame sensor. If your furnace does not ignite, call a professional. Poor or incomplete combustion produces deadly carbon monoxide gas. Make sure you have a carbon monoxide alarm, and test it regularly to verify it is working.


If you hear high-pitched squealing, it may be a sign that you have an airflow problem. Check the vents to make sure they are not blocked. Check that the air filter is clean. A dirty filter restricts airflow, which affects comfort, energy efficiency and the ability of the furnace to function properly.

Low-pitched squealing usually means a failing belt, worn bearings or parts needing lubrication. Have regular tuneups by your heating, ventilation and air conditioning contractor. During a scheduled maintenance session, your contractor will examine every component of the system. If the technicians find worn or damaged parts, replacing them right away keeps minor problems from becoming big.

If your furnace is not performing properly, energy bills are higher than normal or you hear unusual noises, call Martin Enterprises Heating and Air Conditioning to discuss the problem. Our fast, reliable heating repair service will get you comfortable again quickly. We are available every day of the year for emergency repairs in Lake Zurich, Illinois, and nearby communities.

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