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Every time I turn on the heat on, the HVAC creaks loudly and it’s really annoying. It makes noise every time it runs…I can hear the noise in the floor upstairs. It makes sounds until I decide to turn it off completely. Any advice would be appreciated!

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    There are some rather different causes of odd noises. To help us help you: Please describe the sound (rhythmic, random, time between creaks, whether it gets faster or slower, squeak or clunk, etc.). Is it louder at a vent or at the HVAC unit? If the motor speed ever varies, does the sound change (like when the blower shuts off), and what you have done to try to isolate or identify it.
    – MadMonty
    Commented Jan 6 at 6:01
  • Does the sound occur only when the blower starts up and go away for the rest of that cycle? Of is the sound continuous while the blower is on? How old is the furnace and what is the fuel--natural gas, propane, or fuel oil. Commented Jan 6 at 11:40
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    When a home cycles through temperatures, the various materials can expand and contract at different rates, causing noises as they rub against each other. Is that what you're hearing?
    – Huesmann
    Commented Jan 6 at 12:17

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If your HVAC lets you switch the fan between On and Auto, turn it to On while the furnace is not heating the house. If you hear the noise, it's nothing to do with heating, and likely the fan. If you do not hear the noise, it's probably the heat causing thermal expansion somewhere. That will help determine the source of the noise.

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Replace the whole system with a different type of system. Expect to spend a good deal of money doing so, of course.

Thermal expansion happens, and if you have a pile of metal ducts running through your house, they will expand and contract whenever the heat turns on/off. And that will make noise. As will the large fan required to shove air through those ducts, and depending on the duct design there can be additional noise from the air itself in the ducts.

Quiet operation is one of the many benefits of heating (I barely cool, but it's an available function) with cold-climate mini-split heat pumps. A very quiet fan and zero ducts to creak.

For heating-only, a careful installation job (where all sliding areas from expansion are provided with a quiet bearing material, rather than copper on steel squeaky interface) of baseboard hot water can be relatively quiet - a sloppy job will also creak a bit, but generally less noise than hot air ducts. A radiant hot water floor installation is generally very quiet.

A somewhat less drastic (but still pretty drastic/involved/tearing house apart) approach would be to replace many metallic ducts with flexible insulated ducts, but flexible insulated ducts generally have higher flow resistance for a given size, so a duct with similar air delivery may not fit in the space that a rigid/smooth metallic duct was occupying. Such a change would have to be correctly designed and the furnace blower might need to be adjusted or changed out to work with the new ducting in order to work correctly, so it's only somewhat less drastic than a full replacement of the system with a different type.

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Possible noise that may sound like “creaking” Is the settling of your filters. Our two air returns are in the ceiling up and downstairs. When the HVAC turns off and the air pressure pull stops, the filter settles back. You could easily check this and add a buffer/ frame from an older filter with the middle cut out if that is the cause and it bothers you.

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