The blower may sometimes develop low airflow issues. Low airflow may cause the blower to strain to draw in enough air to be heated, resulting in whistling. If your furnace starts making a high-pitched whistling sound, consider changing your air filter or opening all vents to resolve the issue.
Loud Bangs, Rumbles, Knocks, or Booms
Loud noises like this are a sign of a build of gas in a furnace. The noise you hear can mean your heat exchanger is at risk of cracking. Even worse, it's a sign that something dangerous could happen if you continue to use your heater.
A HIGH-PITCHED WHINING NOISE could be shaft bearings that need oil, or it could be a loose, slipping or frayed blower belt, which will need to be adjusted or replaced. Worst case scenario, the blower motor may need replacement. A LOUD BANG OR POP is not a good sign and could indicate that the furnace burners are dirty.
To fix this issue, you should remove dust, dirt, or small items from the ductwork. This will let more air flow through the system and reduce the noise.
Chirping
This can mean that your furnace is simply heating up and the noise is normal. However, it could also mean that there is something wrong with the mounting plate or blower motor.
Chirping – Chirping noises are common in a furnace that hasn't been used in a while. If you hear chirping, and it's the beginning of the furnace season, wait a bit. If the chirping doesn't go away, you may need your fan belts replaced or some similar routine maintenance performed.
Thumps and bumping noises, like an unbalanced washing machine, often indicate an unbalanced blower wheel or motor. This is a serious issue that requires immediate HVAC repair. The blower wheel and motor are major furnace parts and you don't want them bouncing around.
If the pressure builds up, it can cause a whistling noise in the places where the air is escaping. Some dampers can accidentally close while cleaning your home. If you hear an AC whistling noise, try inspecting all of the vents in your home and make sure most of the dampers are open.
We're here for the long run. So if you hear a squeal, a new click, grinding, or popping when your furnace is at any point in the heating cycle, it's best to have a tech take a look and catch things early.
Some of our customers describe a “moaning” sound coming from their furnace. This is typically caused by a problem with the motor bearings—they've likely become worn down and need replacement. Addressing this as soon as possible will reduce your chances of needing a whole motor replacement.
A build-up of debris and limescale is a common cause, particularly in hard water areas. If you notice a build-up of limescale in your kettle, the same could be happening in your boiler. This build-up causes the flow of water in your boiler and heat exchanger to be restricted, leading to a high-pitched whistling noise.
If your furnace suddenly produces loud, sudden banging or booms, you should call an experienced technician as soon as possible. These sounds could indicate stuck ignition, a potentially dangerous situation involving carbon monoxide which is deadly.
Tinnitus is usually caused by an underlying condition, such as age-related hearing loss, an ear injury or a problem with the circulatory system. For many people, tinnitus improves with treatment of the underlying cause or with other treatments that reduce or mask the noise, making tinnitus less noticeable.
The Blower Motor Bearings or Wheel May Be Bad
A bad blower wheel can cause the loud, high-pitched sound you're hearing. The good news is it's an easy fix if this is the problem. You can replace it yourself or call a technician to come out and do it for you. A bad motor can also cause an annoying noise.
If your furnace is making an obnoxious noise, it's likely because the furnace blower motor is turning on and off as part of normal heating furnace cycles. Make sure your thermostat is set properly to the desired temperature and off when you don't need heat (like overnight).
Chirping: If your furnace has been idle for some time, you may hear a chirping noise when you first turn it on. This is normal. However, if the chirping continues or gets louder over time, it could be a sign that your fan belts need to be replaced. Regular maintenance can help prevent this type of problem.
Signs your furnace is going out include inconsistent heating, strange noises, frequent short cycling, a yellow burner flame, and higher heating bills. If it's over 15-20 years old or requires frequent repairs, it may be time for a replacement.
Problems With The Blower
A clogged or dirty filter may reduce airflow through your system and cause whistling noises as the air forces its way through the filter. Loose bolts or other fittings on the furnace may also cause a rattling or whistling noises. One final possibility is that your furnace has a gas flow issue.
High-pitched ringing in the house
Be prepared to call a pro. Electricity can be dangerous if you aren't an experienced electrician. If the high-pitched ringing in your house is more of a whistle, it might be faulty weather stripping around a window or a blocked furnace filter.
The pressure that causes AC compressor whining can be due to a: Refrigerant overcharge, which strains the compressor's piston cylinders. Blocked suction line, which can also cause the system to overheat.
If a thermostat makes a buzzing or fizzing noise when switching this is normally as a result of the switch contacts in the thermostat becoming dirty. The noise is the contacts arcing as they close.
Turn your furnace off immediately, and call a technician to inspect it if it starts making a scraping noise. A scraping sound could point to a serious issue with your blower wheel, and it can lead to considerable wear and tear on your system if left unresolved.
While costs can vary, homeowners can typically expect the following range: Standard Blower Motors: These might cost between $400-700, excluding labor. Advanced Multi-Speed or Variable-Speed Motors: These are generally more expensive, with costs ranging between $650-1250, not including labor.
On a normal day, your home's furnace might make a little noise as it starts up, when it's turning on, and then when it turns off. You can always expect to hear some noise from the furnace. The thing about this noise is that it should never be disruptive.