The humming noises of your furnace can be soothing in the dead of winter when snow muffles sounds from the outside and you are cherishing the toasty warmth of your home. However, some sounds that come from your heating system may indicate problems that you need to get fixed. Consequently, you need to understand the difference between innocuous noises and sounds that should send you to the phone to call HVAC technicians in your area.

If you are confused about the sounds that are coming from your furnace, the following guide can help you tell the difference between harmless noises and those that signify a serious problem.

Pings and Pops

When your home is quiet, you may you may hear pinging and popping noises coming from your heating system. The noises could be the result of two things.

If your HVAC system has metal duct work, the noises may come from the expansion and contraction of metal when your furnace blower turns on and off and as the temperature in the house changes. If the noises seem to happen a lot, it could mean that your ducts are undersized or made of cheap material. These aren't concerning sounds. 

Booms and Thuds

When your furnace burners are dirty, the built up debris can cause a delay in gas igniting when your heating system starts up. During the delay, excess gas builds up. After the delay when the burner ignites, you will hear a boom. The noise can be startling and can even cause the walls to vibrate.

If your furnace starts to make loud booms and thuds, call your HVAC technician as soon as possible. This is not an issue that you want to neglect. Over time, the booms will cause irreversible damage including cracks in the furnace's heat exchanger. These cracks can leak carbon monoxide into your home. Annual furnace inspections and cleanings can help you to prevent dirt buildup on burners.

Metallic Chirping

When the furnace's blower wheels are out of alignment or the blower has warped parts,  you may hear a metallic chirping noise. This sound can be quite annoying over an extended period.

Loose motor parts and worn bearings can also cause the chirping noise. If you are into DIY projects, you can adjust the blower wheels or replace the motor yourself. Check your furnace's user manual for guidance. Otherwise, just call your HVAC technician.

Squeals, Scrapes and Screeches

Loud squeals, scrapes and screeches from your furnace are also annoying and can wake you up in the middle of the night. The high-pitched noises are generally caused by defective blower belts.

When a blower wheel becomes loose, it may start to hit or rub against other metal parts, causing the squealing and scraping noises. If you cannot adjust it yourself to put it back in place, you will need to get it replaced.

Frayed blower belts will cause squeals and screeches akin to scratching nails on chalkboard. If the sound is working your nerves, get the belts replaced. This is another project that you should leave to professionals.

Hiding Harmless Noises

If you are sensitive to noise and do not even like the normal humming of your furnace, you should consider soundproofing your furnace room. Ask your HVAC technician for a recommendation of a retailer or service that provides soundproofing specifically designed for furnace noise control. You can install soundproofing materials that resemble insulation to walls. You can also purchase sound panels to hang on walls and ceilings to mask the sounds coming from your furnace.

If you are in the market for a brand new furnace anyway, be sure to purchase a unit that has an insulated heat exchanger compartment. This will help the furnace run quieter.