Why your ducts are making popping noises

Ever lost sleep due to loud, popping noises that originate from your ducts when you turn your heating on? Popping and banging noises in the duct work are mainly caused by pressure changes that cause the movement of duct walls. Cold air passing through contracts the metal, while heat makes it expand.

There are a number of factors that will determine how much popping sounds you hear. This could be brought about by the shape and size of the duct work, gauge rating or furnace noise.

Duct shape

There are three shapes for duct work: round, square and rectangular. Rectangular ducts are said to be the loudest, while round ducts are quietest. You might think something as basic as the shape might not affect how your duct works, but it actually does. The shape determines how much pressure it can handle. Each shape varies in the pressure threshold that is measured in cubic feet per minute (CFM).

Replacing rectangular ducts to round-shaped ducts is the most logical solution, but it can be expensive. Some technicians will suggest insulating the ducts with fiberglass, or insert a duct liner to reduce the noise.

Duct Size

Small ducts will generally need to expand to accommodate the pressure that passes through them. You will see small ducts expand when the heat is turned on. Heat expands the metal duct, which can then cause the popping noises you are hearing.

If upon inspection you think your ductwork is too small, you will have to consult a professional to calculate the right ductwork size for your home. An expert can provide you with options on how to proceed with your ductwork expansion to get rid of the popping sounds you hear.

Gauge rating of the ducts

Gauge rating represents how strong the metal duct is. A lower gauge rating indicates a thicker and stronger metal that can accommodate more pressure. Thick ducts are less likely to expand at high pressure, and this significantly reduces the noise. The usual ductwork metal has a gauge rating of 24-26.

To make sure that it’s absolutely necessary for your duct work to be changed, you must consult a home specialist and ask for an opinion regarding the matter. Changing ducts is expensive, and it can be costlier if done haphazardly.

Furnace noise

When you have a furnace at home, it can cause the noises that you hear in your duct work. Furnace noise can be carried through the ducts, and this might be what you are hearing.

If you had a new furnace installed and hear popping noises thereafter, chances are the ductwork is not compatible with your newly installed system. It could be that the popping noises start only after you have altered or installed something new to your system. Aside from this, the noises may be due to a delay in furnace recognition, or the vibration and rattles from the blower or fan.

A heating and cooling specialist to check whether the noise is really coming from the furnace. If it is, the professional might put a flexible connecter inserted between the ductwork and furnace to minimize the noises.