You expect your furnace to heat your home – not make noise. So, if it does make strange noises, it’s important to know whether they are ‘normal’ or ‘not normal’.

Humming – The nice quiet hum of motors running and fans blowing and air whooshing through vents all fall under ‘normal’ and we expect our mechanical furnaces to produce them.

Popping – Popping noises are also pretty normal. The first few times you use your furnace especially, you may notice popping sounds when the furnace kicks on and kicks off. This is the sheet metal in your ductwork responding to the pressure of heated air – popping in as a reaction to the negative air pressure of the fan blowing in heated air and popping back out when the fans shut off and pressure is released.

Rattling– You might hear a rattling noise if the fasteners to the metal housing of your furnace have worked their way loose. This isn’t anything serious and can easily be fixed by tightening the fasteners. You might also hear a rattling noise if some piece of debris has become trapped inside your unit, clanking around and possibly causing damage to the fan or motor. If the rattling noise comes from inside your unit, it’s best to shut it off and call a furnace technician.

Thumping– If you hear a rhythmic thumping, you likely have something out of balance, like a blower wheel. This could cause significant problems for the mechanical operation of your furnace. Have it inspected to avoid a potential safety hazard.

Rumbling– A low rumble is normal when a gas or oil-fired furnace first kicks on. However, if that rumble grows loud or lasts too long, it could indicate a serious problem with your burner. In this situation, it’s advisable to turn off the furnace and call for service to avoid a potential safety hazard.

Scraping– A scraping noise coming from your furnace is never a good thing. It usually means a fan blade is scraping up against something it shouldn’t – that means it’s out of kilter and not doing a proper job of facilitating proper air flow. This could lead to a motor blow out. So if you hear scraping – call for help to have it inspected to make sure it’s not something that will lead to motor burnout.

Hissing– Hissing sounds are caused by something escaping. Hissing could mean there’s escaping air due to an improperly installed air filter, or one that is the wrong size. Hissing can also mean there are too many closed vents, or a leak in your ducts.

Whistling– A person who is whistling is probably in a good mood – but HVAC equipment that is whistling is NOT happy. It could be an indication there’s a refrigerant leak in your condenser, or some other thing that’s causing a build-up of internal pressure. This is a ‘not normal’ noise and if you hear it, whistle for a service technician.

Noises are part of everyday life – and even if they’re strange or ‘not normal’ they can be a good warning that something is amiss with your heating or cooling system. To avoid the strange noise syndrome, it’s a good idea to schedule regular maintenance of your HVAC equipment from a local service provider like Jerry Kelly Heating & Air Conditioning. Their trained technicians have seen and heard it all – and they’ll know what you need to keep your system running efficiently at a smooth hum.

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